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Master Buyer's Guide #3435   BackToList   Print
Written: 2018.04.26   Review Date:2020.03.17    LastUpdate: 2020.05.22

How to research parts availability for standards based bikes.

1. Preface
2. Frame Checklist
3. Forks
4. Threadless Forks
5. Threaded Type Forks
6. Stems
7. Quill Stems
8. Clamp on Stems
9. Handlebars
10. Bottom Brackets
11. Cranksets
12. Cassettes
13. Chains
14. Brakes
15. Shifters
16. Front Deraileurs
17. Rear Derailleurs
18. Disk Brakes
19. Rim Brakes
20. Wheels
21. Tires
22. Seats and Seatposts
23. Parts Websites
24. Key Interfaces
25. Reference Websites

1. Preface
This document is aimed at the person who wants to know what parts will work with a given bike. This might be a person who intends to replace some parts on their bike. Or a person who intends to build a custom bike. Or the person who wants to research the components provided as part of a new bike.

Each chapter covers one type of component. Once you read that chapter, then you can look in the specific parts databases in the StandardBikes.ca website.

It explains the standard methods that bikes fit together. Before you buy a bike, you should have some idea of how easy it will be to buy replacement parts. The ideal bike is one that allows you to substitute numerous models of wheels, cranks, chains, handlebar stems into the same bike over the years. The worst bike is one where these parts are attached in some proprietary or undocumented manner, such that you can't figure out how to maintain it. And neither can your local bike mechanic. What is important is standards.

The type of bike we are focusing on are road touring and commuting bikes. The main thing is to get to a point where you know what to look for and what you're looking at. For example, if you know your bottom bracket is a square taper type, then you'll have no trouble finding videos and instructions to take them apart. In a few places, I link to certain videos, to enhance my word description. And I put a few links at the end of the document to useful info.

In getting to know your bike, you might want to have handy a ruler, tape measure, calipers and weigh scale. I'm assuming you have some interest in having a few tools yourself. But for hard jobs, you still want to do them in conjunction with experienced mechanics at quality bike shops. But you need to know enough to specify what you want.

Structure of Chapters: For any given part, the chapter will cover:
  1. Discussion of interface specs (what you need to specify for this type of part
  2. How to distinguish between part types (videos)
  3. In some cases, a link to a more detailed document (eg: Disk brakes)
  4. A summary table showing main interface specs
  5. A link to the database table for these parts

2. Frame Checklist
The "frameset" is the heart of a bike. You can individually change wheels, cranks, gears, brakes, and seat, but if you want to change the frame, you have to start over. This chapter deals with the frame features to note. In this discussion I include the forks as part of the frame and together they are called the frameset.

For sizing, the dimensions you want to pay attention to are the distance from the saddle to pedal, and the "reach" which is the distance from seat center to hand position. The saddle to pedal distance can be altered by sliding out the seatpost. The "reach" can be changed by adjusting or swapping the handlebar stem. Only the wheelbase can't be altered.

Here's what to check on a given frame:

  1. Frame Size
     In the old days, all frames had horizontal cross tubes, and the size of the frame and bike could be specified by the seat tube length. For example, my road bikes all had 25" (63.5 cm) frames. But these days, frames are different shapes, and simply specified as Small, Medium, Large, X-Large. They may also give a length of seat post tube, such as 58 cm, but this is only good within a given model. A more comparable number is wheelbase.

  2. Geometry (Wheelbase)
     When choosing a frame, geometry and fit are just as important as any component. Most discussion of geometry is beyond the scope of this document. Many people will decide based on a test ride. However certain measurements like wheelbase, chain stay length, head tube angle, etc. are worth knowing about so you understand what you are test riding. And these days, you may not actually be able to test a bike in your size and with the components you want.

     A longer wheelbase is desirable for a touring bike because it is more stable and there's more room for panniers. The easiest way to envision a longer frame is to simply lengthen the back triangle. This also makes more room for big tires and fenders. And the riding position is often better if your weight is further back on the frame. The size of wheelbases will vary according to your size of frame. When I measured various bikes, I found it went from 105 to 118 cms. All of my old bikes are about 107 cms. The longest wheelbase I've seen so far was on a full suspension downhill bike which had a wheelbase of 123 cms.

  3. Aluminum, Steel or Carbon frames
     Up until year 2000 or 2010, almost all frames were chrome molybdenum steel (CrMo). But into the 21st century, aluminum frames became cheaper to make, and now many new city bikes are aluminum. Larger diameter aluminum tubing can be made stiffer than steel, which translates into efficiency if you are putting a lot of force on the frame. However steel frames are still preferred for touring because it gives a better ride, and is tougher and can be repaired more easily. Carbon frames are lighter than either steel or aluminum. They are also a softer ride than aluminum. But much more expensive and prone to damage.

     

  4. Fender Mounts
     Ideally when you look at a bike, it already has fenders and rack mounted. But in practice, few are sold that way, so you have to carefully check and visualize how they will be installed. Years ago I test drove a beautiful road bike, and they said they could easily fit fenders. But when I went back to pick it up, it was horrible. The fenders didn't fit at all, so I backed out of the deal. First thing to check is wheel clearance. Is there lots of room for tires up to 35mm. I'm assuming I was amazed to see that all the Trek hybrids I looked at did not have sufficient fender clearance. I've had endless problems over the years with marginal fender clearance on my old Norco road bike. Check to make sure there are mounts for the fender on the dropouts and fork bottoms. If disk brakes, check that the fenders and rack clear the calipers.

    Fenders are essential to minimize the road grit flying up from the front wheel into your drive train. They also keep the dirt off you. Ideally you start with a bike that was designed to have fenders, such as a touring bike. Most fenders are not long enough. It is a handy to extend the front fender with a 10" strip from a Javex bottle, to further reduce road grit. If you do tours with other people, you should extend your rear fender to allow other riders to draft you. This is very common with touring bikes.

  5. Rack Mounts
     Ideally you get a bike designed to take a rack. Look for attachment points on the upper seat stays. And also a separate attachment point on the bottom of forks and axle. Check for clearances with disk brakes.

     

  6. Steel Tubing Diameter and Quality
     All steel frame bikes these days are some sort of chromoly (CrMo) alloy. Aluminum are larger. The diameter and thickness of the tubing affect stiffness and ride. For decades the standard high quality steel tubing was Reynolds 531. The top tube was 1" in diameter and 0.8mm thick walls and double butted at the ends. The seat tube and head tube were a bit larger: 1 1/8" (1.125") and the down tube was 1 1/8. A full discussion of tube diameters is beyond the scope of this document. The most important diameter from a parts swapping perspective is the seat tube inner diameter. And the fork steerer diameters (see forks). All steel bikes you are likely to be looking at have ChMo tubing. Typically the type of tubing will be quoted in the specs, and may be printed on the frame and forks. Eg: On my Rocky Mountain, it says "Chromoly butted". Many aluminium frame bikes have CrMo forks.

  7. Seat Tube Diameter
     The diameter of your seat tube determines what selection of seat posts are available. One standard is 27.2mm, but on my Rocky Mountain it is 26.8.

      Seat Tube
      Rocky Mountain 26.8
      Brodie 27.2
      Aluminum Red Norco 27.2
    Both 26.8 and 27.2 posts are readily available at Bike Doctor.

  8. Head Tube Inner Diameter
     The head tube diameter and length determine what replacement forks could be used. The standard diameter is 28.6mm or 1 1/8".

  9. Bottom bracket Shell
     The bottom bracket shell is the part of the frame that holds the crank axle. The term is used to refer to both the axle, bearings and housing. The bearings thread into the inner diameter of the shell. The only dimensions that are particular to the frame are the width and diameter of the housing. Most common is the shell 68 mm wide and standard english threading. It has been the standard for 40 years. The bearings or bearing cups thread into each side. There are also 70 and 73mm mm wide shells. The majority of touring and city bikes still have a 68mm shell. The most standard crank type is still a square taper, but increasingly there are other cranks like shimano Hollowtech that also fit the same 68mm shell. With carbon frames, the bottom bracket is often a different width, diameter. And instead of being threaded, the bearings are press fit. This is all discussed in more detail in the chapter on cranks.

  10. Rear Dropout Width and axle diameter
     The rear dropout is where the rear wheel slips into the frame. There are several standards for the width of the rear dropout. The most common is 135mm wide and 10mm axle diameter. However all road and touring bikes from the 1980-2000 had 126mm and some 130mm. Mountain bikes have always had 135 mm dropouts, and now most touring bikes and hybrids also share that standard. However as of the last decade, there have been an increasing number of bikes with 142mm dropouts, to accommodate 11 speed cassettes. Strangely enough, many bike manufacturers don't specify the dropout width in their specs. One way to check the dropout width in a store is to look up the model of hub. Old narrow dropouts can be stretched by means of "cold setting" them to the new width. I had a bike shop stretch my old Norco years ago, but nowdays it's hard to find a bike shop that will do it. Below is a summary table of rear dropout widths.

      Old road bikes 126 mm
      Old touring bikes 126 mm
      Modern road bikes 130 mm
      Mountain bikes 135 mm
      Modern touring 135 mm
      Modern Hybrids 135 mm
      Some Thru Axle 142 mm

    The most common front fork dropout width is 100 mm, both on new bikes and for the past 40 years. However, lately some manufacturers have altered this to be wider, but no new universal standard has evolved. For parts availability, 100mm and 9mm axle diameter is still the best choice.

  11. Cable Stops
     Most bikes still have the cables on the exterior of the frame where they are easy to replace. However new models have been appearing with internally routed cables. These are more difficult to replace. It is especially to replace the cable housing. On older bikes like my Miyata, the cable housing was full length. The most likely cable to break is the rear brake cable. On the Norco the housing is held in place with three little clamps that go around the frame. These are troublesome. On the Miyata, the full length cable housing is held in place by built in clamps on the frame. On all the mountain bikes we have, the cables do not have full length housing. Instead, the frame has cable stops, such that the housing is only necessary where the cable turns a corner.

  12. Disk Brake Mounts
     If you are getting a frame for disk brakes then you may want to note which of the three standards the frame uses: Post, Flat, or I.S. (International Standard). I explain this in more detail in the chapter on Disk Brakes.

3. Forks
There are two basic types of forks: threaded and threadless. Each will be dealt with in a separate chapter. Both types of fork have the same way of holding the wheel: a slot which matches the diameter of the axle, and a width to match the axle. The width is called the axle spacing.

  1. Axle Spacing
     Front Hub Spacing. This determines what wheels will fit. The hub has a width and an axle thickness. Typical is 9mm axle on the front (both Miyata,and mountain bikes). You want to know how wide the forks are where the wheel goes into the fork.

      Diameter Spacing -------------------------------------------
      Rocky Mountain Front 9 100
      Rocky Mtn rear 10 135
      Surly Trucker front 10 100
      Surly Trucker rear 10 135

  2. Usually supplied with frame
     (How the forks attach to the frame)
     The forks usually come with the frame, and seldom need replacement. So our discussion is limited to talking about characteristics of various forks already on a bike. At present, discussions about replacing forks are beyond the scope of this document. When you are buying a bike, the material of the forks is often specified separately, because the fork is so important to the ride. For example, it is common for aluminum frame bikes to have a CrMo fork, or a carbon fork. The CrMo fork can be a bit more flexible for a smoother ride. When buying a bike, the material of the forks is often a selling feature. If you were replacing damaged forks, you'd probably try and get exactly the same forks.

    If you changed forks to a different model, you would probably want the advice from a bike mechanic, to make sure you match the rake, steerer length, brake mounts, and axle to crown distance. Discussion of fork geometry is beyond the scope of this document, our main interest is the dimensions that affect what stems and wheels you can use.

  3. Two types of Fork
     When you talk about how the fork attaches to the frame and stem, there are two types of fork: "threaded" and "unthreaded". Up until about year 2000, most bikes had threaded forks. Another name for threaded forks is quill type forks, because they always need a quill type stem. The term "threaded" refers to the outside top of the steerer tube on the fork. It was threaded to allow a cone nut and lock nut to adjust the clearance of the headset bearings. Most bikes now have unthreaded forks which are held in place by an external stem clamp and a top bolt. You can't see the threads themselves on an assembled bike, but you can easily look at the way the stem is attached. An unthreaded fork has the stem clamped on the outside of the part of the steerer tube projecting up above the head tube. A threaded fork ends just above the nut, and a thinner "quill" type stem continues upward. If you are unsure, glance at this video which very clearly shows both types, both assembled and in parts: Bike Guy - Threaded or Threadless?
     Within the first minute, he explains precisely how the threaded system is identified, mentioning the quill stem, the cone. "0:40 ..called threaded because these bolts thread onto the outside of the fork." At 1:10 he shows a threadless fork, where the clamp is on the outside of the fork tube, as opposed to quill type.

  4. Compare old and new design
     The old threaded system allowed bar height to be changed without changing the stem. Normally only a couple of inches, unless you had a really long stem. Often you just had to loosen the top bolt with a 6mm allen key, then pull the bars up or down. Sometimes you had to turn the bolt out a couple of turns then tap it lightly with a hammer to break loose the wedge. Similarly if you were transporting your bike in a box on a plane or train, you could swing the bars sideways or remove the bar and stem assembly.

    With the unthreaded system, you can't adjust the height unless you had a stem with an adjustable stem angle. Most bikes come with a non-adjustable stem. With that, to adjust the height or reach, you need to change the stem. The threaded forks have a diameter of 1 inch, whereas the unthreaded are typically 1 1/8". Some mountain bikes had 1 1/8.

  5. Some Terms
     For this discussion, we need to define a few parts. As you know, a fork has two prongs which join into one fork tube as it enters the frame. This joining location is called the "crown", and the bottom bearing in the head tube is called the crown bearing. The tube that sticks into the frame is called the "steerer". The handlebar stem will be attached to the steerer. The "headset" is the set of bearings that go at either end of the steerer. This includes the crown bearing.

  6. Headset Bearings
     The Headset bearings are the ones that allow the fork to turn in the head tube. There are several systems.

  7. Brake Mounts - Dimension
     The forks need to have brake mounts to match the type of brakes you are using. For example, if you are using cantilever rim brakes, then you need the two pivot points on the front of the fork. These are about 22mm below the center of the rim.

  8. Axle to Crown - dimension
     The "crown" is the place on the fork where it enters the head tube. The part above this is called the "steerer". The bearing at the bottom of the head tube is called the crown bearing. The axle to crown distance is the distance from the center of the axle to the bottom of the crown.

  9. Rake
     The "rake" of the fork is how far it sticks forward from the centerline of the steerer. Imagine a line going through the center of the steerer. The rake is the perpendicular distance from that line to the center of the front axle. Classic road forks used to curve forward near the bottom to increase the rake, and cushion the ride. Some mountain bikes have a gradual curve forward (my Rocky moutain). And some abruptly angle forward just below the crown bearing (Brodie).

4. Threadless Forks
This chapter deals with how the "threadless" type forks interface with the frame and with the stem. As you know from previous chapter, threadless forks slide up into the headtube, and then the stem clamps onto the outside. Thus the key dimension is the outer diameter of the steerer tube. The inner diameter doesn't matter. The length of the steerer tube should more or less match the length of the headtube. But typically spacers collars are used for 1 or 2 cms, to make the bars higher. For example on the Brodie rigid frame mountain bike, there is a shiny spacer several cm long.

The other minor dimension is the "dust cap" bolt that threads downward into the top of the steerer tube. It is screwing into a thin washer like holder inserted into the tube. It is often used as a temporary measure to pull the forks into proper position prior to tighening the main stem clamps.


  Steerer
  Diameter ------------------------------------- Yellow Brodie 28.6 Standard Steerer 28.6

  1. Steerer Outer Diameter
     For threadless, the outer diameter of the "steerer" determines what handlebar stems are available. Sometimes head tubes are larger than But head tubes can have "reducers" The standard is 28.6mm which is 1 1/8". The other thing often specified is 15mm Top Cap.

  2. Steerer Length
     This must be longer than the frame head tube, such that it sticks out enough at the top to allow the stem to be bolted on. There is usually extra length for a 1 or 2 cm spacer collar as well. The number of spacer collars affects the height of the bars, as does the stem length and angle.

5. Threaded Type Forks
(Quill Type forks) As mentioned in the general chapter on forks, the threaded type forks are held into the frame by a large nut which threads onto the end of the fork. Actually there are two things that thread onto the steerer tube: first a notched nut, then a large hex nut. That attaches the fork into the frame.

Now we must talk about how the handlebar stem attaches to the steerer tube. Unlike the threadless design, the stem is inserted down INSIDE the steerer tube. That is why it is called a "quill" design. The quill of the stem has a diagional wedge on the bottom end, and when a top bolt is tightened, it pulls the wedge sideways to jam it into the steerer tube. Thus the key dimension is the inside diameter of the steerer tube.

  1. Typical Fork dimensions


      Inside Steerer
      Diameter Length -------------------------------------
      Rocky Mountain 22.5
      Norco 10 speed 22.5
      Miyata 1000 22.5

  2. Steerer Inner Diameter
     For quill type, the inner diameter is the key dimension for attachment of the old quill type stems. On my Rocky mountain it was 25mm, but on both my old road bikes it is 22mm.

  3. Steerer Length
      This is the length from the "crown" of the fork to the end of the steerer. The length of the steerer tube must match the head tube length of the frame. The threads need to allow the threaded nut that adjusts the headset cones to be tightened down. This is what holds the fork into the frame.

6. Stems
The stem is the thing that connects the fork with the handlebars. There are two basic types:

  1. Quill stem (threaded fork on older bikes)
  2. Clamp on stem (threadless fork)

To attach to the steering tube of the fork depends on the fork type. There are two fork types: "threaded" and "Unthreaded". See the previous chapter on forks. Threaded forks take a "quill type" stem, and unthreaded forks take clamp-on stems. Glance at the following quick videos if you don't know the difference.

  1. Quill Stem Video
     The video is mostly about quill stems, but right at the start they also mention the "threadless" stem, which I call the "clamp on" stem. You only need to watch the first 3 minutes to know everything about ordering a new stem.

  2. Threadless Stem Video
     Video is about "threadless" stems, which I call a "clamp on" stem.

  3. Buyers Guide
     To familiarize yourself with the modern external clamp stems read this: ChainReactionCycles.com.

  4. Height adjustment Comparison
     The old quill type allows you to adjust the height without changing the stem. With a clamp-on stem, you can't adjust the height. The stem clamp on position is determined by the length of the fork steerer tube. There may be spacers between head tube and clamp, but for any given fork, the position is fixed. However if the stem has an adjustable angle, then you can swing the bars up or down in an arc.

  5. Reach adjustment
     Assuming you can't move the bars far enough forward with an angle adjustment, you need to change the stem. A basic stem costs less than $50.00. Assuming you have clamp on handlebars, it's pretty quick to change the stem. Changing the stem requires removing the handlebars. This is easiest if the handlebars are attached with a two piece clamp. The old quill type stems used to hold the handlebars with a closed, one piece clamp which makes the bars difficult to remove since you need to strip them and slide them back out thru the stem. If you are going to do any amount of experimentation with the stems, get rid of that old stem.

     

7. Quill Stems
This chapter discusses changing the older quill type stems. The first thing is to get rid of any stem with the old single piece handlebar clamp. Once you've gone thru the process of removing all the brake levers, shifters, grips, and handlebar tape, and converted to a stem with a two piece handlebar clamp, any further experiments are easier. To find stems, look up "quill type stem" on Amazon. Below are the key dimensions.

I assume if you were buying a new stem, you'd get one where the handlebars bolt on). And may as well be adjustable stem, so you can vary the angle. Look up "Quill Handlebar stems" on Amazon). Typical cost is 19.95 + shipping.


  QUILL STEMS
  *1 *2 *3 *4 *5
  Quill Bar Quill Stem Stem
  Price Diam Diam Len Reach Angle --------------------------------------------------------------- Tabitha's old bike 22.2 25.4 150 80 Promax Extra long 22.2 25.4 300 85 0-20 Sunlite Adjustable 19.95 22.2 25.4 180 110 Blue Norco Stem 22.2 25.4 75+75 110 Miyata 1000 22.2 25.4 80+60 120 0 Rocky Mountain 25.2 25.4 40+70 130 10

 *1 Quill Diameter: Diameter of the quill which inserts into the fork tube. The quill diameter you need is determined by the internal diameter of your fork steering tube. Various sources give the standard as 22.2 (7/8". My Miyata measures 22.2. Park tools talks about 22.2, 25.4 and 28.6 So I assume that 22.2 is 7/8".

 *2 Handlebar diameter: is almost always 25.4 mm (1 inch) on old bikes. When I looked in Amazon, it is rarely specified. Park tools video talks about 22.2, 25.4, 26.0, 31.8 and 35.0, but on commuter bikes I've seen it is 25.4.

 *3 Quill length:
 Give two numbers: Inserted part first, then visible. Eg: Rocky Mountain is 70+40
 (Height) Park calls this "Quill Length", measured from bar center to bottom of the quill. Since the bottom is diagional, I use the midpoint of the diagional. Quill stems typically have "minimum insertion line". Diagrams on google define "Height" as the height from minimum insertion line to center of bar. On my Miyata, the overall quill length is 140mm, with only 60mm above the minimum insertion line, and 80mm below.

 *4 Reach:
 Park Tools calls this "Stem Length". The distance from the center of the quill to the center of the handlebars. This is the length of how far forward the bars are from the upright. On some models such as Sunlite, it is not given, but you can guess from the picture it is about 80 mm.

 *5 Stem Angle:
 Park tools defines this as the angle the stem reach drops from the horizontal. This corresponds to an acute angle (<90 degrees) between the quill and the reach. Classic road bikes had an acute angle such that the stem reach ended up horizontal. This requires a drop from a 90 degree angle to compensate for the angle of the fork tube. (perhaps 6 degrees?). In some models, the angle is adjustable. Eg: Sunlite
 

8. Clamp on Stems
See Stem Database As explained in the general chapter on stems, clamp on stems go onto threadless forks. To order a new clamp on stem, here are the key dimensions: They refer to the top part of the clamp as the "face plate".


  CLAMP ON STEMS
  *1 *2 *3 *4 *5
  Price ForkD BarD Angle Reach Weight --------------------------------------------------------------------- Oversize Standard 28.6 31.8 Old standard 28.6 25.4 BW Handlebar stem 28.5 25.4 35 105 BW Handlebar Stem 28.5 31.8 35 120 Wake MTB Stem 28.5 25.4 0 90-110 Fomtor 28.5 25.4 7 60 Yellow Brodie 28.5 25.4 35 90 Evo Adjustable 59.00 28.5 25.4 Adj. 105-125 370 Evo E-Tec 34.99 28.5 25.4 35 60-110 161 Zipp Service CSL 179.00 28.5 31.8 4/6/8 70 140

 *1 ForkD:
 Fork Diameter. Outer diameter of Steerer tube. Often not specified for replacement stems, but I assume it is standard on the type of bike we are talking about (hybrids and old mountain bikes). 1 1/8" (1.125" or 28.5 mm).

 *2 BarD
 Handlebar diameter in mm. Typically clamp on stems are specified according to the handlebar diameter. Most common is 25.4mm which is 1 inch. New bikes often have "oversize" ones at 31.8. See bike chart.

 *3 Angle
 Angle in Degrees is a measure of the slope up from the clamp. It can range from 0 to 45 degrees. One that is 45 degrees is going to make your handlebars higher.

 *4 Reach
 (Reach) Length in mm is the distance from the center of the handlebar to the center of the steerer tube. But this cannot be measured directly, you need to lay the tape measure in a position where you can estimate it. Method of measuring depends on the handlebar clamp. Eg: On Brodie, if you remove the handlebar clamp, you can then measure from the flat surface to the center of the handlebar stem.
 A long one is going to put the handlebars further forward.

 *5 Weight
 The weight of the stem. Note that the adjustable stems are heavier.

 *6 Stack Height "Stack Height" means how much of the steerer tube is covered by the stem. Eg: If the steerer tube sticks up 60 mm, and the stack height of a given stem was 41mm, then you would need spacers for 19mm. It would seem that it is useful to know the steerer tube stack height above the head set. The Zipp Service Course stem gave the stack height of 41mm, and that may be close to a standard. I measured the Yellow Brodie to be 40 and spacers 25 so total stack height would be 65mm..

 *7 Clamp Width
 

9. Handlebars
As has been discussed in types of bikes, you can't easily switch between drop bars and flat bars. So this chapter only discusses changes to bars within each type. There are often good reasons for changing the bars.

  1. Clamp Diameter
     The key dimension needed to order new bars is the diameter where it attaches to the stem. The ISO standard diameter of handlebars was 25.4 mm (1 inch). All four of older bikes have this size. But nowdays 31.8 mm (1.25 inches) is the new standard. Many handlebars have a thinner diameter at the ends than at the clamp. The standard handlebar clamp for road bikes went from 26.0mm to 31.8mm diameter in the early-mid 2000’s, improving lateral stiffness. Note that both road and mountain bikes had adopted this new shared standard, whereas older mountain bikes used a 25.4mm bar that was NOT cross-compatible with road’s 26.0mm. Summary:

      25.4 both road bikes and mountain bikes
      26.0 temporary road bike standard
      31.8 current most standard

     25.4 was truly not thick enough. My Miyata 1000 has 25.4mm bars, which flex quite a bit if I stand up to pedal. Some of this flex could be twist in my long 130mm stem but more stiffness in the bars might also be good. So the new standard makes sense.

  2. Grip Area Diameter For all types of bars the grip area diameter is standard. Drop bars are 23.8mm and flat bars are 22.2 mm. So components like shifters and brake levers rarely specify this measurement.

  3. History of how the bars attach
     Before the 1990's the standard stem was the quill stem with a one piece clamp. Changing the bars with such a stem was a problem because you had to remove all the grips and brake levers to slide the bars back through the one piece clamp. However since 1990's, most stems now have a two piece clamp. You remove the cap via two or four bolts, and then easily remove the handlebars. The type of clamp doesn't make much difference for the bars. In either case all the levers, grips, etc need to be transferred.

     

  4. Cut Long Bars
     Most mountain bikes come with bars that are far wider than you need for city use. These long bars spread you out like a sail in the wind. And they also make it awkward to get your bike into bike racks. On our bikes, we cut all the bars to a shorter length.

  5. Other shapes of drop bars
     On a bike intended for drop bars, there are several other common shapes of bars. The ends can flare way out. The ends can come back and around. Sheldon Brown talks about "trekking bars" or butterfly bar which wrap back at the same level. See
     
Videos:
  1. Favorite Handlebars This video he shows about 5 or 6 different shapes of bar, and discusses each one. He is going to swap out the bars. He shows the kind of quill stem you want, which has a two part clamp and faceplate. But he never really shows driving with hands on the top hood.

  2. Zach Gallardo
     He breezes through three main types of bars. At about 5:00, he starts to discuss drop bars, and gets into 4 main hand positions. Tops, Corners, Hoods and Drops.

  3. Drop Bar Dimension Definitions "How to measure drop bars" The tricky thing is that if you rotate the bars in the clamp, you can alter the "drop". My standard is to have the forward project level. That way you can rest your hands there when you don't need the brakes. That often results in the final end section being down sloped.

    Drop: The vertical distance from the center of the bar top to the center of the deepest part of the bend. A drop of 125mm or less is considered shallow; 125-128mm is medium; more than that is deep.

    Drops: Straight portion of the bar that extends back toward the rider.

    Hooks: Section of the drop just below the brake-lever clamp that is used during descending and cornering.

    Ramp: The segment that transitions from the top to the hooks. It is sometimes measured by the steepness of the angle to the point where brake hoods are installed.

    Reach: Horizontal distance from the center of the handlebar top to the center of the furthest extension of the bend, where brake hoods are mounted. A reach of less than 80mm is short; 80-85mm is medium; 85mm or more is considered long.

    Width: Most companies measure a bar’s width between the center of each drop. Common sizes are 38, 40, 42, and 44cm.

  4. Comparison Table
     Numbers in cms.

     
      End
      Drop Width Reach Rise ------------------------------------------------------
     Blue Norco 13 35/35 0
     Miyata 1000 35/40 3

    Drop: The easiest drop to measure is to put a ruler across the end of the bars, then use a second ruler at the center to get the height. I call that the "End drop". If the bars gradually slope down like the Miyata, then the end drop can be misleading, because where you actually have your hands while able to operate the brakes is higher.

    Drop2: Thumb drop, is the drop at the point where you are on the drops and ready to operate the brakes. It may be higher than the end trop if the straight part is dropping. Eg: On Miyata, One possible point of confusion in measuring "Drop" is that on the Miyata 1000, the bars rise slightly from the clamp before dropping, whereas the Norco bars do not rise. For this situation, we take the center at the clamp, and ignore the rise.

    Width: On Miyata bars, the drop flares out. Hood width is the width measured at the top of the brake levers. End width is the width across the tips of the bar. On a flared bar like the Miyata, the two widths are 35/40. On the Norco, it is 35/35

    Rise: The amount the bar rises from the clamp.

    So to quote width, use the center of the level part.

     

10. Bottom Brackets
The "bottom bracket" of the frame is the housing for the crank axle and bearings. Despite being part of the frame, the term "bottom bracket" usually refers to the crank axle and bearings. This chapter is just general stuff about bottom brackets, the two main types are threaded and press fit. These will be dealt with individually in the next two chapters.

     

  1. Octalink
     However, there have been several developments since the 1990's that have become common. First, Shimano developed a proprietary system called Octalink which replaced the square taper with 8 splines. Octalink still has end bolts just like square taper, and the procedure for changing cranks is the same. See video:

    The next change was Shimano and others developed "outboard bearing" systems to move the bearings outside the shell. This makes room for larger bearings and also larger diameter spindle. In fact, the spindle can now be hollow. Typical spindle is 24mm. A typical system like this is Shimano Hollowtech. In this system, the crank is only two pieces: the chainside crank and the axle are one piece. There are no pullers or end bolts. The left side crank is held onto the axle by two pinch bolts.

  2. Comparison
     It seems that the Hollowtech is not necessarily better than square taper for touring. Although theoretically stronger, the outboard bearings are now more exposed to dirt and rain. I know one regular commuter doing 20km/day who needed to replace her Hollowtech bearings a couple of times over a few years. And certainly if you look up "Hollowtech bottom bracket failures" on google, you see that most people expect to replace them every year or two. I suppose one advantage of Hollowtech over square taper is the cranks are less likely to work loose and become partially rounded.

    So far all these new systems are designed for the same old standard 68mm threaded frames. But as of 2020, 73mm bottom brackets are also common. See my table of bike models.

  3. Press Fitted
     Recently many carbon frames now have the bearings press fitted into them, rather than screwing into the bottom bracket. In these, the shell is typically wider, and bigger diameter than the BSA standard. About a dozen new standards have appeared for press fitted

    11. Cranksets
    The "crankset" consists of the front chain rings and pedal arms. In most cases, they are a separate part from the "bottom bracket" which is the axle in the frame. This is called a "three piece" crankset: two cranks and the axle. However recently certain models have come out that combine the bottom bracket and crankset.

    1. Pulling the Crank
       As explained in the Bottom Bracket chapter, the most common method to attach cranks and chain rings is square taper. A bolt theaded into the end of the axle presses the crank onto the tapered end of the axle. To do a good job, you should really reef down the bolt. To get a square taper crank off, you need a special crank remover. (Park CCP-22 or Octalink uses CPP-44. When you install cranks, you've got to make sure they are really tight to push the crank onto the end of the square taper. (30-45 Newton Meters of torque). It is quite common to not tighten these up enough, and then the crank works loose and you get "clicking" as you pedal. And eventually looseness can cause the inside surface to become slightly rounded against the square taper such that the cranks need to be replaced.
        This excellent video explains the whole thing Park Tools Crank Removal

    2. Removing the Bottom Bracket
       Removing the bottom bracket axle and bearings is a separate subject from removing the cranks. It is in the chapter on bottom brackets. Once you've got the cranks off the square taper, another special tool is necessary to remove the bottom bracket cartridge.

    3. Steel or Aluminium chain rings
       Steel is harder than aluminium. On my Rocky Mountain, it originally came with polished Aluminium cranks and chain rings. They were like jewelry. However after a single brutal Port Renfrew trip with lots of rain on logging roads, the drive train was trashed. In theory the chain rings are individually replaceable, but each one cost as much as a whole crankset. So I replaced the whole crankset with a Shimano Acera crankset for $50. That included all three chain rings plus new aluminium crank arms. It is pretty well the same number of teeth as I had: the standard triple chain ring: 42-32-22 teeth.

    4. Chain Ring Guard (Pant Leg protector)
       (Bash Guard) These days most cranks you see on city bikes have a built in "chain device" (guard) on the outside of the largest ring. On a mountain bike, these function as "bash guards" because they protect the chain rings from damage when hitting a rock. For city use, these guards have proved to be very useful in protecting my pant legs from going into the chain ring. I wear normal city clothes when riding my bike. However, none of my older bikes have these guards. And I think the more expensive cranks these days also don't have the guards. On my Norco ten speed, I have a 52 tooth Shimano 600 chain ring I frequently catch my pants, even though I try to keep them tucked into long socks. I always commuted in normal clothes, like in Europe. Similarly the chain ring is exposed on my Miyata 1000, but I don't use it around town as much.

    5. Number of chainrings and Teeth
       For Vancouver touring, you want all three chain rings on the front. Trying to reduce to a "2 by" system or a "1 by" system will limit your range of gears. A typical hybrid bike such as the Devinci Stockholm has a triple chain ring 48/36/26. A typical mountain bike chainring such as the Acera on my Rocky Mountain is 42/32/22. These typically operate with a 11-32 cassette on the rear. So the lowest gear is 22 on the front and 32 on the rear.

      However, there are currently various "gravel" bikes being sold that have gone back to only two chainrings. In the old days a common crankset on a road bike had 52 teeth on the largest sprocket, and 40 on the second. (My Norco from the 1980's). These days most gravel bikes have a "compact" crankset which is 50/34. So the second cog is much lower than the old 40 tooth. However nowhere near as low a gear as the triple on the Stockholm, which has 48/36/26. Individual chain rings can be exchanged as long as the "Bolt Circle Diameter" of the crankset is the same. But these days, replacing individual chainrings is often just as expensive as a whole crankset. Even if you are replacing, you are limited by the bolt circle diameter. The old standard BCD was 130mm, and the 34 tooth needs 110mm.

    6. Chain Ring Width and number of speeds
       Can you use an 8 speed chain on a set of chainrings designed for 9 speed? The 8 speed chain is slightly wider than a 9 speed. However there is no problem with the wider chain, because the front cogs have to be quite far apart anysway to accommodate the chain angles. And the width of the teeth is pretty standard, because the internal roller widths are the same.

    7. Crank Length
       Almost all cranksets on touring/hybrid bikes are between 165 and 175mm. My bikes are 170 and 175. Even though I am 190 cm tall, it seems my 170mm are better than 175 mm. Since power is force times velocity, with a shorter crank arm and the same force on the pedal, you would need a higher RPM to generate the same power.I've seen arguments that shorter cranksets can generate more power, but since they aren't readily available it doesn't matter.

      12. Cassettes
      See Cassette Database for list of cassettes. See the detailed part document titled Cassettes for even more detail.

      What is a cassette? It is the cluster of gears on your rear wheel. The term "cassette" refers to the way the cassette slides onto the hub. The original 10 speed bicycles in 1970 up until the 1990s did not have cassettes, they had what was called a "freewheel" which screwed onto the rear hub. My 1986 Miyata 1000 still has this system. These "freewheels" contained not only the cogs but the bearings and ratchet mechanism. (Hence the word "freewheel as opposed to a fixed cog). But in the 1990's Shimano developed a new system called Uniglide whereby the cogs were a separate part. The bearings were now in a core hub which they called the "free hub". Note the term "Free hub" as comared with "free wheel". With uniglide each cog was a separate piece, and you could replace just one cog. But then to improve shifting they developed a system called "Hyperglide" with tiny ramps on each cog to the next cog. these cogs were sold as a matched set, and people replace the whole set. These cog sets are called "cassettes". With the cassette system I've never heard of anybody replacing individual cogs. The cogs are not sold separately, and even if they were, the argument is usually that the whole cassette needs replacement.

      Over the years there was a gradual increase in the number of cogs on the back. The original 5 speed freewheel was replaced with 6 speeds. By the time uniglide came out, 6 was the standard. Then the cassettes started having 7 speeds, then 8, 9,10 and even 11! These extra gears were squeezed in first by increasing the "dishing" on the rear wheel (which made it weaker), and then by increasing the width of the dropouts from 126mm to 130mm and finally 135mm. To go from 7 speeds to 8, they made the chain slightly narrower (7.3mm to 7.1mm). But you could still use one of these 7-8 speed chains with any cassette. But to go to 9, and beyond, each time they had to make the chain narrower and the cogs thinner. Above 8 speeds, each number of cogs has a special chain. All this adds expense to the manufacture, and adjustments more fiddlesome. And they wear out faster.

      Fortunately new bikes are still available with 7 and 8 speed cassettes. For example, most of the new bikes at Bike Doctor are 7 and 8 speed, with a few 9 speeds sprinkled in. And the 7 and 8 speed cassettes are widely available from multiple manufacturers, so the parts aren't going to get hard to find. (In fact you can still easily buy old freewheels which is what I have to do with my Miyata!

      If buying a new bike, keep in mind that maintenance costs will be substantially less if you have 7 or 8 speeds. As I mentioned, the highest recurring cost of operating a bike are drive train costs. On my current bike, I'm using a $12 KMC chain and a $16 cassette, and they work perfectly.

      1. Max 8 Speeds
         You can cut the costs substantially if you use 7 or 8 speed cassettes rather than 9, 10 or 11 speed cassettes. With 3 chain rings up front, you don't need more than 8 sprockets on the back. The problem with the 9, 10 and 11 speed cassettes is that the cogs are spaced increasingly closer together, and so the chains have to be narrower and everything is more likely to going out of adjustment. Not only are the replacement cassettes less expensive, the chains are also less expensive. 7-8 speed chains can be removed for cleaning by a reusable master link, whereas 9 speed chains and above you must replace the master link each time. And the 8 speed cassettes last longer because the teeth can be wider.

      2. Replacing chains
         Chains wear out faster than cassettes, and running a worn chain eats into the cassettes. See separate chapter on chains.

      3. Replacing Cassettes
         To replace a typical 7 or 8 speed Shimano cassette, you need to remove the lock ring. It's really simple once you know how. There are lots of videos, all you need is a cassette puller, a big wrench and a chain whip. On my bikes, I'm using cassettes that are $28 or less, and chains that cost $14 or less. So my drive train costs are reduced to less than $50/year.

      4. Friction Shifters
         All bikes before 1990 had simple friction shifters instead of indexed shifters. A friction shifter is just a lever held in place by friction. It doesn't click into gears, it just smoothly moves the chain left and right. They work with every cassette. You just move the lever till the chain goes up to the next gear. They never need adjustment because there is no adjustment. And they never change even if you change from 7 to 8 speed. Unfortunately, they are no longer mainstream. Instead, all new bikes have systems like Rapid Fire shifters which integrate both the brake lever and the shifter. And they have no friction mode. And if they are out of adjustment, most people need to get a mechanic to adjust them. All my bikes have friction shifters on them.

         To eliminate adjustment hassles, use friction shifters rather than indexed shifters. Some index shifters have a friction mode. An indexed shifter is tied to a certain number of cogs, and a certain cog spacing. So a 9 speed shifter won't work on an 8 speed cassette. But friction shifters work on whatever cassette you want. And never need tricky adjustments.

      5. Big Sprockets last longer
         Over the past decades, the industry has kept reducing the number of teeth on both front chainring and rear sprockets. The old 10 speed standard was 52 teeth on the front, and the smallest on the back was 14 teeth. But now the typical front chainring is around 38 teeth, and back cassettes have as few as 11 teeth. For the same 2:1 gear ratio, 52 teeth running on a 26 tooth rear will last way longer than 30:15. The reason is that with bigger sprockets, there is much less force required in the chain to transmit a given amount of torque. Furthermore the force is spread over more teeth and the chain bends less with each revolution. And worse still, the chain side plates and bearings are thinner. It all adds up exponentially to greatly increased wear. When riding, try to pedal in the largest pair of sprockets, so I shift to the large one whenever possible. The chain ring you wear out is usually the middle one.

      6. Is Derailleur specific
         If you decide to downgrade a bike from 9 speed to 8 speed, will you have deraileur problems. The answer is no. The indexing is controlled by the shift levers not the deraileur. So you will need to change the shift levers if you downgrade. Or use friction shift.

         

      13. Chains
      In my discussion of cassettes, I outlined that the chains are different sizes as you increase the number of cogs. For a 7-8 speed cassette, you need a corresponding chain. This chapter goes into the details of chains.

      1. Replacement
         When replacing a chain, you need to know the number of cogs on the rear cassette. The number of cogs determines what width of chain you need, because as you increase the number of cogs, the cogs get thinner and closer together. So chains are specified in terms of number of cogs. The most standard size is the 6,7,8 speed chain, which works on any one of those cassettes. 9 speed, 10 speed and 11 speed cassettes each have their own width of chain.

      2. Measurement Summary
         This is more detail of the above. It gets into what exactly is different about the different "chain speeds". First, as background, all chains have 1/2" pitch. The 1/2 refers to the length of each link, pin to pin. However there are three main widths. 3/32, 11/128 and 1/8. The 3/32, 11/128 and 1/8 refer to the width of the space between the inside sideplates. (called "Inner Width"). What makes a 9 speed different than a 10 speed chain is not the inner width, it is the construction and thickness of the side plates.

         - Multi speed chains from 5 to 8 have inner width of 3/32" (2.38mm)
         - Multi speed chains from 9 to 12 speeds have a width of 11/128 = 2.18mm

         6,7,8 speed 2.38 mm
         9-12 speeds 2.18 mm

        From BikeGremlin: Chains for one and multiple speeds differ from each other by the outer width. The more "speeds" a chain is designed for, the thinner the outer plates and shorter the pins are (and they protrude less) – so the outer chain width is smaller (i.e. chain is narrower). Inner width of all the multi speed chains is almost the same – with only single speed chains having a significantly larger inner width.

        See https://https://bike.bikegremlin.com/3555/bicycle-drive-chain-dimension-standards/] BikeGremlin Drive Chain standards[/a]

      3. Chain Widths and Pin width
         From the KMC and SRAM websites, you can see the pin width varies with the number of speeds. The thing that you want to know is the "pin width". There are a lot of sloppy specs on the web. The KMC Z51 box says pin width is 7.1mm and the KMCX8.93 is 7.3mm. When I measured the width with my vernier caliper it was .1 mm wider, the 7.1 measured 7.2 and the 7.3 measured 7.4. The boxes specify three things: Pitch 1/2 inch, roller width 3/16, and pin width 7.1mm.

        Below is a table summarizing the specs given on the KMC website.


          Sprockets Pin Length Weight 116) ---------------------------------------
         6,7,8 Speed 7 mm 330g
         9 speed 6 mm 272g
         10 speed 5 mm 257g
         11 speed 5 mm 243g

        From the above, you can clearly see that the more sprockets you have, the narrower the chain. A chain for an 11 sprocket cassette is only 5mm wide. Each increase in number of speeds increases the price by 50% or so. And above 8 speed, you can't reuse the master link. So you can't just take off your chain to clean it.

      4. Master Links
         Before 8 speeds, chains did not have a master link, you just pushed out the pin from any link with a chain breaker tool. However this often resulted in "stiff links" so with the 7 and 8 speed chains, they now include a "master link". The master link has special side plates such that when the adjacent rollers are pulled together, the pin comes out of the plate. To remove a 7-8 speed chain there is a special tool you want called master link pliers. The tool is Park MLP-1.2 which cost $25. (MLP is Master Link Plyers). On 7-8 speed chains the master link is reusable, so you can take the chain off and clean it if you want.

      5. Plating (What about SRAM chains)
         At MEC, I bought the PC870 for $28, but then when I checked my journal, I noticed I had only paid $15.95 for a a SRAM PC730 at Bike Doctor. What's the difference between PC870 and PC730? The answer is on the SRAM website: The PC870 is nickel plated, and with chrome hardened pins. Whether this makes much difference in lifetime I don't know. I guess nickle plated looks better, and might prevent rust, but I ride my bike often enough I don't have a rust problem. So why pay more?

        To get the chain page, use google "SRAM Chains" and go to https://www.sram.com/sram/mountain/component/chains, then scroll down to the 8 speed, then click on "Specs".

        Comparison Table

        Model     USD          Outer plate   Inner plate  Pin Treatment
        ------------------------------------------------------------
          PC 830 10.00 grey grey Standard
          PC 850 14.00 grey grey Chrome Hardened
          PC 870 19.00 nickel grey Chrome Hardened
          PC 890 33.00 nickel nickel Chrome Hardened

         

      6. Chain Lubrication
         Keeping your chain lubricated is essential. I notice a huge difference in how easy it shifts after lubrication. So we used to use oil. Yet oil picks up grit and quickly turns into heavy black grease. The gunk builds up between the sprockets, and in the derailleur, and even on your tires. The "experts" talk about wet lube and dry lube. Wet lube is for wet weather and sticks better. More like oil. It also picks up more dirt. Dry lube is "wax based". It doesn't pick up dirt as much, but has to be reapplied more frequently. Both of them are equally smooth when applied.

        I'm not a lube perfectionist. Mostly I'll just put a bit of lube on the chain, spin it a couple of times, shift gears to spread it around, and then go riding. The crudest lube strategy is to just use regular oil and take your chain off and clean it periodically in solvent. But taking it off is too messy and time consuming. So people look for ways to clean the chain without removing it. This is done using a chain cleaner tool. These have a clear plastic basin into which you put the solvent. Then you push the chain down into it and little brushes remove some of the gunk. (Search MEC.ca for "chain cleaners"). But that is still messy and I only did it a few times.

        The final solution is to lubricate with wax, not oil. This is called "dry lube" and comes in a squeeze bottle. In the past year, I did an experiment: I put on a new chain, and used "dry lube" entirely rather than oil. It is a wax based lubricant that doesn't pick up dirt. After a year, there has been zero buildup of black gum, and the chain runs as smooth as with oil. However, I tend to have to relube the chain every 40 km or so. Oil sticks much better, and Betsy went back to oil during the rainy season. But I intend to continue to use the wax lube. However, the inexpensive $12.00 chains I use tend to get cosmetic rust on the outer sideplates if the bike is out in the weather for days. My chain turned rusty looking. But once I applied more lube, it ran as smooth as ever. If I don't like the look of the rust, I could buy a slightly more expensive chain that is zinc plated.

        Here is a video where the guy makes his own wax based lubricant from candles, paraffin oil, and Xylene or mineral Turpentine. Oz Do It Yourself I'm not sure I'd go to the trouble, because the little $16 bottle I got at MEC lasted more than a year.

      7. Chain stretch
         Chains "stretch" and then wear out the cogs more quickly. The metal in the chain doesn't actually stretch, what happens is the road grit wears away the pins joining the links, allowing the links to stretch out in the space. Park tools makes a simple metal bar called a "chain wear indicator which tells you if your chain should be replaced. (Park tools CC-3.2) I've read articles that say the oil conveys the road grit into the chain links, which I suppose is another argument for the dry lube.

      8. How often to replace
         Most experts always say you should replace the chains as soon as they become stretched, and thus reduce wear on the cassette. Typically, you'll go through 2 or 3 chains before you need to replace the cassette. Never the less, what many people do is wait for the whole system to wear out so much the chain starts to skip, then have a shop replace the whole thing. This can be about $300. But that worn chain wears the cassette faster. As the chain stretches, it is being supported by fewer and fewer teeth. The cassette will last longer if you replace the chains more frequently. The notion that a worn cassette will wear a new chain faster is false because it is the grit that stretches the chain, not worn cassettes. So you can afford to change the $12.00 chain and stick with the old cassette if it still works.

      9. How much stretch
         In a year of commuting, Betsy's all season bike stretched her chain a whole link. The Park tool CC3.2 Chain Checker indicated the chain needed replacing for some time. But we ignored it, just intending to replace the whole drive train. But when I discovered inexpensive chains, we changed the strategy and started replacing just the chain as soon as the tool says.

      14. Brakes
      The biggest decision is whether to get a bike with disk brakes or to stick with rim brakes. Disk brakes work better and don't wear through rims. But you have to learn how to adjust them. But some types of rim brakes can also be tricky to adjust. One particular problem is fiddling around with the "toe in" to eliminate squeal. Another problem is to make sure they don't get knocked out of adjustment and rub on the tire. We've had a $60 tire destroyed by rubbing not noticed.

      1. Expense Comparison
         There are two aspects to expense comparison:
          Cost of pads.
          Cost of wheel replacement
          The cost due to changing pads is comparable. Disk pads may last a bit longer, but cost more. Rim brakes require new brake pads, these days can be $10 for good ones. Disk pads are about $20.

      2. Market share
         As of 2020, most hybrid type bikes advertise disk brakes. But many touring bikes and road bikes advertise rim brakes. For road bikes, the factor is they are lighter. For touring bikes, it's about the simplicity.

      3. Wheel Removal
         If you regularly remove wheels to ship the bike, or put it in your car, disk can be tricky. Supposedly you need a spacer to make sure the pads do not get pressed together.

      4. Summary Rim Brakes
         - lighter
         - cruder and simpler to troubleshoot
         - chew through rims if used regularly in rain

        Disk Brakes
         - more braking power
         - more sophisticated
         - work better in rain

      See the following 2 chapters for each type.

      15. Shifters
      See Shifter Database Also Shifter Field Help

      In the 1970's on till about 1990, the gear shift mechanism on all derailleur bikes were little levers mounted on the down tube. There were two levers, one for the front chain rings and one for the rear freewheel. The shift cables ran down the outside of the tube to the deraileurs. To shift gears you just reached down and moved the lever quickly forward or back and the gears would shift. This was the simplest system ever developed: short cables and totally independent of how many gears.

      Then in the 1980's or so, some bikes put the shifters on the end of the handlebars. These are called Bar End shifters. The original bar end shifters were also just friction.

      In the 1990's Shimano developed indexed shifting. They standardized the spacing of the chain rings and cogs, and then built shifters that clicked the cable just the right distance from gear to gear. This system was called "Indexed" shifting.


        BarType Indexed Combined ------------------------------------------------- Trigger Flat Indexed no Thumb Flat Both no Twist Flat Indexed no Combo Flat Indexed Yes BarEnd Drop Both no Downtube Drop Friction no STI Drop Indexed Yes

      FLAT BAR SHIFTERS

      1. Trigger Shifters
         The definition of a trigger, as opposed to a thumb shifter is that there is an actual spring release into each gear. And they can't be put into friction mode.

      2. Thumb Shifter
         These can be either in friction mode or indexed.
         The original flat bar shifters in the 1980's could operate in either friction mode, or indexed mode. I have always run mine in friction mode because it's simpler. They still sell this type of flat bar friction shifter, but they are rarely put on mainstream bikes.

      3. Combo
         Combined brake lever and shifter for flat bars. Eg: Shimano Altus ST-EF500

        DROP BAR SHIFTERS

      1. Downtube shifters
         Downtube shifters are still the simplest and most flexible system. The adjustment is simple: just two "stop screws" on the deraileur, to prevent the chain from coming off at either end. It is up to the rider to move the lever an appropriate amount to shift the gears. Once you are used to them, you just flip the lever forward or back a littleand you get the next gear. If you really want to shift quickly several gears, you pull the lever a bigger amount. Downtube shifters work perfectly well with the latest cassettes. And if you want to change to a cassette with more or less cogs, it is no problem because the shifter has no notion of how many cogs there are.

      2. Bar End shifters
         Bar end shifters are still common on touring bikes with drop handlebars. They stick out of the ends of the handlebars, and the cables run under the bar tape to the bend in the bars and then go back to the deraileurs. They can be used in either friction or indexed mode.

      3. Integ STI
         The most common type of shifter these days on drop bar bikes uses a combined brake lever and shift mechanism. Typically you flip the lever sideways to shift gears, whereas the brakes you pull in. Shimano calls this "STI" shifters (Shimano Total Integration)

      For all types of shifter, the grip area diameter of the bars is seldom listed, because all normal drop bars are 23.8mm and all normal flat bars are 22.2 mm.

      16. Front Deraileurs
      For a table of models, see Front Derailleur Database. Like many other components, deraileur standards have become a jungle. The scope of this chapter is to cover only the types of derailleur that would be replacement parts for standard touring and gravel bikes. It is limited to 7,8,9 speed derailleurs. And to SRAM and Shimano. And round frame tubes.

        Here is an article to get started: Bike Radar SRAM and Shimano 2015

      The article talks about 3 things:

        Cable Pull (top, bottom, dual)
        Mount Types (Low clamp, High clamp)
        Gearing

       

    8. Cable Pull
       Yellow Brodie is top pull. The cable comes down the seat tube. The 1970's Norco Shimano 600 is bottom pull. The cable comes down the front tube to a boss, then curves around in a piece of cable housing just above the bottom bracket, and goes up the seat tube to the derailleur. The Rocky Mountain is top pull: the bare cable comes across the top tube to a boss, turns the corner in a piece of housing, then bare cable down the seat tube. The Miyata 1000 is bottom pull: The bare cable comes down the front tube then under a double yoke brazon on the frame and up the seat tube to the derailleur.

    9. Cable pull ratio.
       The deraileur itself does not control the indexing, but how far the derailleur moves for a given movement of the cable can vary. This is cable pull ratio. The word "leverage" is also used.

    10. Chainring size
       You never needed to worry about chainring size with band clamp derailleurs as you could just match it by sliding the derailleur up and down the seat tube.

    11. NumGears

    12. Band Diameter
       Clamping to a round seat tube, the derailleur band clamp needs to be matched in diameter. Common sizes include 34.9mm, 31.8mm and 28.6mm. The Norco and Rocky Mountain are close to 28.6mm. The Miyata 1000 measures almost 30mm.
       

      17. Rear Derailleurs
      See Rear Derailleur Database And the detail document Derailers

      First of all, some spelling. Sheldon Brown says the English way to spell the word is derailer, not the french word derailleur. And increasingly the Youtube videos all refer to it as the "mech" (mechanism). This is based on the term "gear mech". By whatever name, the derailer is the device that pushes the chain off one cog and onto the adjacent cog. The shifter pulls the cable a certain distance and the derailer shifts the chain.

      There are roughly two things you need to specify to replace a derailer:

        1. How it mounts to the frame
        2. The cage length

      Speeds?
       Derailers are independent of the number of speeds. There is no such thing as a "9 speed" derailer, as opposed to a 10 speed derailer. Although the cogs on 8,9,10,11 speeds cassettes are all spaced differently, the amount the derailer has to move is controlled by the shifter. The derailer just moves however far the shifter pulls the cable. However, when you look up various derailer models in the Shimano specs, you see that they specify "compatible chain". Eg: RD-T6000 is titled "Shimano Deore Long Cage Rear Derailer 10 Speed for Trekking". However Sheldon Brown is rightfully skeptical of this distinction. He says: "Within a given brand/style of rear derailer, all "speed numbers" are generally interchangeable. This applies to all indexable models, basically everything manufactured since the late 1980s."

      Mounting:
       The mounting system for derailers has become a jungle. On older classic touring bikes, the derailer bolts right onto the frame. But on the new bikes, the derailer mounts onto a separate derailer "hanger" which is non standard for each manufacturer. There is a separate website just to sell these spare hangers. And furthermore, there are two types of mounting: direct mount versus "standard" mount.

      The literature on these two mounting systems is quite confused. However, at least one person told me that most touring bikes have standard mount.

      Clutches
       Some derailers for mountain bikes feature clutch systems to prevent the chain from bouncing when going over rough terrain. However this feature is unnecessary for touring bikes and beyond our scope.

      18. Disk Brakes

      1. Disk Brakes
         Disk brakes require that the wheels and frame be designed for disk brakes. The two interfaces are as follows:

          (1) How the rotor attaches to the wheel
          (2) How the calipers attaches to the frame and fork

        I explain each interface below.

      2. Frame Interface
         How the calipers attach to the frame. The frame needs bolt holes to hold on the caliper. As of 2020 there are three systems:
          Post Mount
          Flat Mount
          I.S. mounts (International Standard)

        The Post Mount system has threaded holes perpendicular to the fork. You just bolt the caliper onto either the fork or the frame.

        The Flat mount is also threaded holes. But the holes are in different spacing.

        The I.S. mount is just eyelets, not threaded holes. An I.S. mount always requires and adapter to fit whatever caliper you want. The advantage of unthreaded holes is you can't strip them. The Surly trucker has I.S. mounts. IS mounts are unthreaded eyelets 51mm apart that bolts run through parallel with the hub axle. (As opposed to 90 degrees like the post mount). In almost all cases the brake caliper is then bolted to an adapter that has one set of threads for the IS mounts and another 74mm apart for the caliper. For more detail see Disk Brake Standards - Detail

      3. Wheel Interface There are two standards for how the disk is mounted on the wheel: Centerlock and 6-bolt. Bike Doctor says 6-bolt is most common, for commuter bikes.

      4. Rotor Diameter Most common rotor size is 160mm. Many road bikes have 140 on rear, 160 on front. The rotor diameter determines where the caliper should be mounted on the frame. The standard right now is 160mm disks for road bikes, 180mm for mountain bikes. However many gravel bikes also advertise 140 rotors.

      5. Rotor thickness
         Shimano are 1.8mm thick, and should be replaced when reduced to 1.5mm.

      6. Pad Size
         There seem to be different size types of pads, because when you look up a given pad, you see a compatibility list. Eg: Shimano M05 is compaible with BR-C601, but J04C is compatible with BR-M9000, MM785, etc. And within each type Pads are mostly standard size but vary in material. Eg: The following at MEC:

          Shimano B01S Resin pads 12.00
          Shimano J04C Metal disk pads
          Shimano M05 Resin disk

         

      7. Mechanical or Hydraulic Disks:
         Once you have specified the type of frame mount, you have to decide between mechanical versus hydraulic. Mechanical disk brakes are activated via a cable. Hydraulic are activated by oil pressure.

        Mechanical are more basic if you were out in the hinterlands and needed repair. Hydraulic are smoother. Fortunately, you can change brake systems on any given bike. A basic set of hydraulic calipers and levers is about $250.00.

        I've talked to people that had trouble adjusting their mechanical based disk brakes. It seems the hydraulic type might be easier to adjust and replace brake pads. But maybe harder to overhaul - you may have to bleed the hydraulic lines. On a basic disk brake the pads are about $20, and people who ride mountain bikes regularly replace them every 6 months. It would be interesting to know how often the pads need replacing, and how often the hydraulic lines cause trouble.

      19. Rim Brakes
      This chapter covers various types of rim brakes, as opposed to Disk brakes. Rim brakes are the traditional brakes.

      1. Rim Brakes
         There are three main types of rim brakes:
         1. Center Bolt (caliper is attached by single center bolt)
         2. V-Brakes (cable is horizontal direct pull)
         3. Cantilever (cable comes vertically from above)

        Here is a quick "identification" video which shows all the variations of cable actuated rim brake callipers: Park Tools Brake Identification video

        Center Bolt:
         The traditional center bolt mounted brakes found on old ten speeds and modern road racing bikes are nothing but trouble, because they don't have adequate clearance for fenders. They are often hard to adjust. Both cantilever and V-brakes (linear pull brakes) are mounted by means of two built in pivot points on the frame. You can change from cantilever to v-brakes because the pivot points are the same. However, you'd need to change brake levers because V-Brakes have about twice as much "cable pull" as cantilever. (15mm as compared with 7 mm of pull). The force in the cable is half as much but it moves twice as far. But the brake arms are twice as far from the pivot, so the actual shoe moves with about the same force. And the brake lever force is about the same as it moves through about a 20 degree arc.

        Here's how to tell the difference between "direct pull" V brakes and cantilever: With V brakes, the cable pulls horizontally, whereas with cantilever, the cable pulls vertically. With V Brakes, the main cable goes through a 90 degree curved sleeve called the "noodle". There is only one cable and it pulls the two arms directly together. With cantilever brakes the main cable pulls vertically up on a yoke. Below the yoke there are two cables, one for each side. There is probably a bit more friction in the cantilever system, but both are better than the old "center bolt" mounted caliper brakes.

        This video shows linear pull V brakes Linear Pull.

        Brake Levers:
         V-Brake levers move the cable twice as far when you squeeze the lever. So the brake levers are specific for that type of brake. If you've got drop handlebars, you can't just use the standard integrated road brake/shifter levers to actuate V-Brakes. Although there are "long pull" levers for drop bars like Tectro RL520, these expect a separate shifter mechanism. One other solution for using your existing levers is to use a thing called a "travel agent" which is a pulley mechanism that makes the cable on the far side move twice as far.

        Cantilever Variations:
         There are several sub-types of cantilever brakes. Fortunately, the types are interchangeable, so if you really don't like one type you can buy new brakes. The first type is the "straddle cable" type. With this type, the main cable terminates at a yoke which pulls up on the center of a straddle cable. My Miyata 1000 has this system. More common these days is the "link unit" type. In these, the main cable goes directly thru a junction point and to one of the brake arms. From the junction, a second little cable runs to the other side. The whole assembly is called a "Link unit".

        Centering Adjustment:
          In many cantilevers, one of the arms has a separate adjustment screw which allows you to balance the springs. When the main cable is released, both arms spring outward, and leave lots of clearance between the shoe and the rim.

        Return spring:
         The return spring is the spring that returns the brake to it's "out" position when you release the brake lever. You want enough tension that the brake always returns all the way out when you release the lever, so it doesn't tend to drag on the rim. Many cantilevers allow you to vary the overall tension by means of 3 holes into which the return spring can be seated. The top hole gives a lot more return spring tension.

        Wheel Removal:
         Check how easy it is to unhook the brakes to remove the wheel. On V Brakes you simply pull the two arms together and pop the cable up out of the 90 degree cable guide. Very simple. With the "link unit" cantilevers, you pop the short cable out of it's socket. Only the straddle cable is difficult. For some reason, on my Miyata, the only way to get the wheel out is to remove one of the brake pads and arms. Very cumbersome, and you need to realign everything when you put it back.

        Brake shoes:
         Brake shoes can be from $5 to $20. It seems that the expensive ones really do work better. I bought a pair of Kool Stop half Salmon brakes and they really do work better than the old cheap ones I had. Most of the reviews on Youtube seem to agree.

        Smooth Post versus Threaded Post Shoes:
         The brake shoe post is the thing that holds the actual brake shoe. On cantilever brakes, there are two types of brake post: smooth and threaded. The threaded one is adjusted via an allen socket right in the end of the post. The smooth ones are held in place by a cross bolt. I think the threaded ones may be slightly easier to adjust because you can hold the shoe in the correct orientation as you tighten the allen key. Types of pad

        20. Wheels
        A wheel is made up of a hub, spokes, and rim. But nowdays the whole wheel is sold as one item. So when buying wheels, you must sort thru the specs to figure out which ones are associated with the rim, the hub. Here is a link to a database of some common wheels: wheelxLister.asp

        CHECKLIST For either a front or rear wheel you need to check the following: For each item, look for the corresponding heading in Wheel Detail.

         - Rim Diameter (26" (BSD 559) or 700c (BSD 622)
         - Brake Type (Rim or Disk)
         - axle type (quick release or thru axle)
         - dropout width (usually 100 for front or 135mm for rear)
         - valve type
         - number of spoke holes
         - spoke gauge
         - rim width

        For a rear wheel, also check:
         - freehub length Eg: 8/9/10

        Typical Wheel Specs from HLC.bike:

        Position Front
        Wheel Diameter/ISO 26'' / 559
        Axle Type QR
        Hub Spacing 100mm
        Freehub Body -
        Wheel Tire Type Clincher
        Wheel-Brake Comp. Rim
        Rim Material Aluminum
        Rim Construction: Double wall
        Rim Internal Width: 18.4mm
        Rim inner width range 0-21.9mm  (I don't know what that is?)
        Rim Color Black
        Hub Model Formula FM-21-QR
        Rim Drilling 36
        Spoke Type Stainless
        Valve Schrader
        Rim External Width 24.4mm
        Depth 16mm
        Rim Model Alex DM18
        Skewers Included Yes
        

        21. Tires
        Tires are the one thing that when maintaining a touring bike, you don't want to cut costs. With cassettes and chains, I gladly cut costs, but not tires. Kevlar belted tires to prevent punctures are a must. In the old days, I got so many flats, whereas now I have Schwalbe tires, and have not had a flat in years despite constant riding. On my road bikes, I have 25mm to 32mm tires, and inflate theto 80 PSI. On my mountain bike I have fatter tires, and inflate to 60 PSI. After a week, they tend to lose 20 PSI, so I need to pump them up once every week or two. I have a good floor pump costing $100.

        1. Tire Diameter
           The tire diameter must match the "Bead Set Diameter" of the rim. Rim Diameters are discussed in detail in the "Wheels" chapter. To summarize, the ISO standard for talking about tire sizes is the "Bead Set Diameter" (BSD), and this is 622mm for both 700c and the 29ers. If you look carefully, this is printed right on any quality tire. On old mountain bikes (26") the BSD was 559 mm.

        2. Tire Cross Section
           The tire cross section (width) determines how robust the tire would be for hitting rocks. In the old days, we did many tours that involved travel on gravel logging roads. From experience, we know that 25 mm tires would get several flats every trip. On old 10 speeds we used special order 35mm tires. I'd say the smallest you want to go for a general touring/commuting bike is 28mm. I currently have 32 mm tires on my Miyata touring bike. On my converted old 10 speed, I've got 25 mm tire on the rear. But for an all round touring bike, you probably want 32mm tire width.

        3. ISO Tire Notation
           The official ISO method of giving tire sizes is the width followed by the BSD. Eg: 25-622. This is the number you'll see printed somewhere on quality tires, along with designations such as 700c.

        4. Inches to mm
           Tire cross-sections on road bikes have always been measured in mm, whereas on mountain bikes you commonly ask for inch sizes. On my old mountain bike, I've got 1.75 inch which is 47mm, quite a bit bigger than 35mm tires you might find on a hybrid. That size of tire allows me to use the bike on some smooth single track or gravel as well as roads. Note also that the old time fractional measurements like 1 1/2 inches cannot be directly converted to mm. Sheldon Brown has two different tables, one for fractional and one for decimal inches.

        5. Tire profile
           Even tires that are nominally the same cross section can be different. The tire can be oval shaped or pear shaped, with a point.

        6. Wide Rims
           When mountain bikes came out, the fad was to have really narrow rims, and then huge tires. This made the wheels light, if you ignore the tire. But the latest thought is that for a given cross section area, you want wide rim, because aluminium is lighter than rubber. These arguments rage on the internet. From a practical standpoint, wider rims make it easier to fix flats, because there is more room to position the tube stem.

        22. Seats and Seatposts
        See Seatpost Database

        1. Seat Post Diameter
           When buying a seat post, you need to get one that matches the inner diameter of your frame tube. This is different for different frames. The seat post diameter is usually stamped near the bottom of the seatpost. If not, you have to measure it. On my Rocky Mountain, the new alloy post I bought is stamped 26.8 mm, but I had to measure the old post. Sheldon Brown says 27.2 mm has become more of a standard. However when you measure a seat post with a caliper, you discover they can vary slightly, and are not really exactly round and uniform. I initially measured mine to be 26.8 mm, and in places is not completely round.

          At MEC.ca website, you can see a typical seat post called MEC 350mm Alloy Seat Post. 350mm is the length. That model comes with the following diameters to fit different tube sizes: 25.4, 26.8, 27.0, 27.2, 30.0, 30.9

        2. Seat Post length
           On all my old road bikes the seat post was quite short, usually 160 mm. For safety, you want at least 100 mm of the post to be inside the frame tube, so on my old bike, the highest the seat could be adjusted was 60 mm above the seat tube. For a typical mountain bike, the lengths are much longer, often 350 mm or 400 mm. On my Rocky Mountain bike, I have a relatively small frame and I use a long 400 mm seat post (since I am 6 foot tall).

        3. Offset
           The simplest seatpost does not have any "offset" or "layback". But if you want to get a bit more length out of a given frame, you can consider a seatpost that is offset back from the centerline of the seat tube.

        4. Seat Attachment Clamp
           First, lets talk about the seat itself, and then the clamps. The seat itself has two parallel rails. The post has one of three types of clamp which tighten onto these rails. The seat rails allow you to adjust the seat forward or back. The clamp allows adjustment of the angle of the seat. There are three main types of clamp as listed below. Three types of clamp are:

           1. Two bolt system (2 vertical bolts)
           1. Rocker clamp (one vertical bolt)
           3. Single cross bolt with toothed washer

          It's difficult to explain the different types of clamp if you haven't seen them. So I refer you to a couple of high quality videos. In the videos, pay attention to the method of adjusting the seat angle.

        5. Bikebarn.ca Video
           The woman in this video shows the three most common systems of seat attachment. She starts with the single bolt, rocker type seat post. She shows how to slide it forward and back with the rails and how to adjust the angle.
           0:00 She starts with what I call the "rocker Clamp" system
           2:06 She briefly shows what I call the single cross bolt system
           2:20 Introduces what I call the "Two Vertical Bolt" system

        6. Clint Gibbs Video
           This video shows how to swap out or install a seat. His main emphasis is the "two bolt" system, which is what I prefer. He also quickly shows a single cross bolt system. Good explanation of "bottom plate" and "top plate". He emphasizes keeping the bolts in place when changing the seat. Has a lot of irrelevant detail regarding grease on the bolts, torque wrench, etc. At 3:40 he talks about why he prefers the 2 bolt system.

        7. Adjusting Seat Angle
           Controlling the angle of the seat is much easier with the two bolt seat posts than with the old single bolt / rocker clamp posts. As was shown in the Clint Gibbs video above, the method of adjustment is to loosen one bolt and tighten the other. This gives you exactly the angle you want. By contrast, the old rocker clamp system is harder to control the angle. You think you've got the seat at the angle you want with the bolts loose, but when you tighten it, it changes. So you had to iterate away to get the angle you want. And any adjustment, you had to start all over.

        8. Problems with Rocker clamp system
           All my bikes came with the old single bolt rocker clamps, and on all my bikes I was always at one extreme end of the rocker post adjustment. I had a particular problem with my Rocky Mountain because even with the rocker clamp at one extreme end, the nose of the seat was still too high. And also the little rocker teeth were worn away such that the seat angle could slip. The situation was made worse by having a soft seat, because then my pelvis would sink into the soft back of the seat, making the nose relatively higher. A ball breaker. So the first thing I did was replace the seat with a standard firm seat. This improved things greatly, but I still had the curved clamp at the extreme end of the adjustment. But then I discovered the two bolt seat posts, which give you total control over the angle of the seat. So I bought a new post for 24.00 and easily put it onto the bike. The new seat setup is much more comfortable.

        9. Seat Post clamps
           The height of the seat post is adjusted by sliding the post up and down in the frame, then tightening a bolt or clamp which compressed the seat tube of the frame. The seat tube has a slot about 5 or 6 cm long which allows the clamp to tighten on the tube. Traditional road and touring bikes simply had a built in bolt which pulled the tube together. With mountain bikes, the clamp became a separate item. The clamp could be either a quick release, or via an allen key. You can easily change clamps. Some people prefer bolt clamps to quick release because it makes it slightly harder to steal the seat.

        10. Seized Seat Post
           A common problem is seized seat posts. They can become bonded to the frame tube by corrosion, and can be very difficult to remove. Don't let this happen, because there are lots of times you want to be able to remove the seat. And check any used bike you buy. I recommend you quickly loosen the seat post clamp once every few months and make sure it will twist and slide easily. Last week I discovered one of our seat posts had seized solidly in the frame. Yet a year ago we could easily remove it when putting the bike on top of the car. The normal recommended way to twist the post is by using the seat itself as a wrench. However that didn't give me enough leverage in this case. Eventually I had to use a huge 15" crescent wrench on the flat section at the top of the seat post, and with all my strength I could just barely twist it. But it was still tight, no matter how many times I exhausted myself twisting it back and forth. I sprayed WD40 into it for several days, but it didn't get looser. Eventually I took it to a bike store, and at first the mechanics had no more success than myself. But eventually I told the mechanic to get the biggest adjustable wrench and I would twist the saddle while he pulled up. So I twisted back and forth and he pulled up, and the post gradually came up. The amazing thing was that once it was out, the WD 40 oil covered the surface and it would slip right back in with no problem.

        11. One piece or two
           On all the traditional one piece seat posts I have, there is a flat section at the top of the post just under the seat. That flat section is 22mm wide. To twist a stiff seat post, I inserted a giant adjustable wrench onto this section and twisted. However the bike mechanic was initially concerned it might twist off the top of the post, since the top is usually a separate piece. However, twisting with a wrench is no different than twisting with the seat, just a bit more leverage. My new two bolt seat post does not have this section, and may in fact have the top clamp attached in some manner.

        23. Parts Websites
        PARTS WEBSITES

          What I want in this chapter is a list of useful websites, in which you can browse their inventory for what you are looking for.

          1. HLC.bike
             This is the ultimate website for seeing what is available when you order parts. It is the website used by bike stores to special order you the parts. HLC does not sell directly to the end user, but you can use their website to get the part number, then go to your local bike store and tell them to order the part. The way the website works is you click on "Catalog" on their front page. This gives a huge list of about 50 types of part, like Stems, Wheels. To use the catalog, go to their home page, and click the triple menu bar in upper left corner. then click "Catalog" in the drop down. Then click "View by Category". This displays a huge list some of which are not types of bike part. But you'll find Stems, Wheels, etc. Under each, you can filter by various attribues. For example, under wheels, choose "Front" To actually order the part, just write down the part number and get your local bike store to order that number. For example, lets see all the front wheels for one of the old 26" wheel (BSD 559) mountain bikes.

          2. Chain Reaction
             This is a huge database in the US,and useful for finding out what exists. For example if you were wondering about the existance of a stem longer than 130mm you would look here. Or all the different Shimano cog clusters.

          3. Bike Doctor
             "Shop Now" has a list of part types. Eg: Stems, Wheels. For each, if you click, you can filter on price, brands. And if you click on a given item, you see some of the key dimensions.

            Below are useful websites for understanding different specs.

          1. Sheldon Brown
             Almost everybody who does any amount of study of bicycle standards will come across the Sheldon Brown website. It is the most comprehensive database of measurements and standards that exists. In addition to current standards, he has quite a bit of historical stuff.

          2. Park Tools - Calvin Jones Videos
             Calvin Jones of Park Tools has prepared a systematic set of videos showing all the common adjustments to brakes, drive train, etc. Just watching the videos, I was able to see the key adjustment features that my own brakes were missing. The videos are really concise and they use incredible photography, cut away parts and certain video techniques to quickly make the point. I would assume that production of these videos are a core part of Park Tools strategy. Here are some examples:

            1. Crank Removal and Installation
               Note how he starts off making sure you understand the different types. Note that there are cutaways of key parts. Note the preparation that must have gone into this video.

            2. Brake Caliper Mounting and Adjustment - Cantilever Smooth Post.
               Note the way the part he's talking about lights up as he mentions it. This is what I mean by special video techniques.
               
            Park Tools also have prepared written documents on these subjects. For example Bottom Bracket Standards.

          24. Key Interfaces
          Below are the key characteristics of any bike that determine what parts you can interchange. Listed in order of importance.


            Dropout BBShell Disk Diam Seat Fork -------------------------------------------------------------
            Miyata 1000 126 68 - 27.2
            Surly Trucker 135 68 160 28.6
            Trek 520
          1. Dropout width
             The dropout width is the inside width of the frame where the rear wheel fits. The dropout width determines how easy it is to buy replacement wheels. The standard these days is 135mm. Old road bikes before the 1990's had 126mm and some have 130mm. For maximum interchangability, you want 135mm. Some touring bikes now have 142.

          2. Fork Diameter
             Fork outer diameter, Fork Steerer Outer Diameter
             must match Frame Headtube Inner Diameter)
             
             All forks slide up into the headtube of the frame. On a modern bike with threadless forks, this also determines the stem diameter.

          3. Steerer Inner Diameter
             This is the key measurement on quill type forks. Fortunately it was always standard 1 1/8

          4. Rim Diameter
             Eg: BSD 559, 584 and 622
             The marketing people refer to 26" wheels, 29" wheels, 27 1/2", 700c, etc. This wheel size system is flawed because it includes the tire, which of course changes if you put on fatter tires. The correct way to specify rim diameter is by the "Bead Set Diameter" (BSD). This determines what replacement tires will actually fit. It is the inner diameter where the tire bead seats. On all hybrid and touring bikes the BSD is 622mm, (nominally 700c). On old mountain bikes the standard diameter was nominally 26 inches (BSD 559). Really old vintage 10 speeds had 27" wheels, which were BSD 630mm. And 29ers are again just BSD 622.

          5. Rear Wheel Freehub length
             (Cassette-Wheel interface)
             This is something you want to know when buying a wheel.
             The freehub length determines which cassettes will fit a given wheel. Most people with indexed shifting will just replace a cassette with the same model. But with friction shift, you can upgrade from 7 sp to 8 sp, etc. Typically nobody talks about the actual length, they simply refer to the two lengths as "7 speed" and "8,9,10" speed. The second size will fit 8,9 and 10 speed cassettes. These days if buying a new wheel, an 8,9,10 speed freehub is most flexible. A freehub that takes 8 speed cassettes can also take 7 speed. All you need is a little 4mm spacer, very common. But a 7 speed freehub cannot take an 8 speed cassette. It is not long enough. The 8 speed length is likely to remain most common for many years, because the same length will accommodate 8,9 and 10 speed cassettes. Whereas 7 speed freehubs will only take 7 speed cassettes. So 7 speed wheels are less common. The freehub length determines which cassettes will fit. There are two lengths: 7 speed, and 8,9,10 speed. To put a 7 speed cassette on 8,9,10 hub requires a 4mm spacer. These are very common. If you have index shifting, I'm assuming you'd stick with whatever number of cogs your bike came with. Otherwise to change from 7 to 8 requires changing the shifters.

          6. Handlebar Stem type
             Modern bikes all come with "threadless" external clamp forks and stems, as opposed to the old Quill type stems. The original quill type stems also had the old single bolt compression slot system to hold the bars. However, you can now get a quill type stem with a two part clamp, and do a one time conversion. Cost $30.00

          7. Seat Post Diameter
             The seat post is something you might want to change. The only measurement that matters is the inside diameter of the downtube on your frame. The most standard is 27.2mm.

          8. Bottom Bracket Shell width
             Most bikes these days still have the standard Shell width of 68 mm, and a sealed cartridge. This has been the standard for 40 years. Some new mountain bikes have a 73mm shell width but this is less common.. Within that, the most common interface with the cranks is the square taper cranks. Recently in my survey at Bike Doctor, the vast majority were still square taper cranks.

          9. Brake type
             Choosing between disk or rim brakes is a decision that is usually made when the bike is bought new. To change a bike from rim brakes to disk involves getting different wheels, frame mounts, brake levers, etc. So you are unlikely to do this. For disk brakes, the standard way the disk is mounted on the wheel is either the 6 bolt interface, or the Shimano centerlock. The standard disk rotor size is 160mm.

            With rim brakes, there are two main types: horizontal pull v-brakes versus vertical pull cantilever brakes. Although you can change between them, you typically also change the brake levers, which may involve the shifters on most hybrids. So you are likely going to stick with the system you have.

          25. Reference Websites
          What I want in this chapter is a list of useful websites, in which you can really do a study of what is standard. Two ways to verify standards is to (1) Look up replacement parts, and (2) Look at the standards used by manufacturers selling bare frames.

          1. HLC.bike
             This is the ultimate website for seeing what is available when you order parts. It is the website used by bike stores to special order you the parts. HLC does not sell directly to the end user, but you can use their website to get the part number, then go to your local bike store and tell them to order the part. The way the website works is you click on "Catalog" on their front page. This gives a huge list of about 50 types of part, like Stems, Wheels. To use the catalog, go to their home page, and click the triple menu bar in upper left corner. then click "Catalog" in the drop down. Then click "View by Category". This displays a huge list some of which are not types of bike part. But you'll find Stems, Wheels, etc. Under each, you can filter by various attribues. For example, under wheels, choose "Front" To actually order the part, just write down the part number and get your local bike store to order that number. For example, lets see all the front wheels for one of the old 26" wheel (BSD 559) mountain bikes.

            - I specified 26" 559, and then it showed 16 wheels.
             - I picked one with a Alex Rims DM-18 rim. I looked up the specs for that rim on the Alexrims website. It is a double wall, with 24mm wide external, and 18 internal. The "18" is probably the model number.

             

          2. Bike Doctor
             This is an example of one of the many local bikes stores that all use the same point of sale software. "Shop Now" has a list of part types. Eg: Stems, Wheels. For each, if you click, you can filter on price, brands. And if you click on a given item, you see some of the key dimensions. Where this data comes from is importing an entire "catalog" from one of the suppliers like HLC, and then they may add a few items themselves. They typically only stock a fraction of what you see on their website, and special order the rest.

             

          3. Bikerumor
             This is a pretty good explanation of all the latest "standards" trends for higher end bikes. Broken out by categories, similar to what I do. Eg: If you want to read about bottom brackets, go to the correct section. Many of the standards they promote are not what you'd put on a world touring bike, but are interesting because you do come across them.

          4. Surly Long Haul Trucker
             You can get a pretty good idea of what are the most standard interfaces these days by studying the Surly specs. Click on the link and then click "Specs and Geo". You'll find out the enduring standards such as 68mm bottom bracket, and you'll also see the names of the most standard brake callipers, etc. These bikes are better standards reference because there is a whole industry of little shops that build up bikes based on these frames. The frame will accommodate the widest range of parts.