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Geometry Websites #3469   BackToList   Print
Written: 2020.04.30   Review Date:2020.04.30    LastUpdate: 2020.07.18

Information websites, Geometry Calculators

1. Preface
2. Geometry Sites
3. Cycling Builder

1. Preface
The main thing in this document is a list of several Geometry websites.

2. Geometry Sites
Both these websites allow you to compare the geometry of various bikes.

  1. Bike Radar
     2021.06.05 A document with diagrams and definitions of stack, trail, etc.

     Geometry comparison. Allows you to select two bikes, then lists the specs side by side. I compared a Surly LHT 2018 with Trek 520. I see trail is much higher on Surly than Trek. They also have 1985 Miyata 1000 LT in all sizes. Their size data for miyata came from

     Has a form where you enter some measurements, and it adjusts the diagram. So you can design your own frame.

  4. Bike Exchange Geometry Charts
     SaysStack and Reach immediately tell you if a bike will fit you. But then handling is determined by Head Tube, then they get into Fork,Rake and trail. Says Top tube effective is good way if Stack and Reach aren't given. Finally Chainstay and wheelbase, and BBDrop.

3. Cycling Builder
Summary: This is a program I briefly investigated which theoretically has all the mechanical relationships between parts. Eg: You pick the frame, and then pick the parts that will go with it.

Conclusion: Does not work well enough to be useful for me. I started with "Frame", and I saw the Surly LHT. I got as far as "cassettes" and noticed that there were zero 8 speed cassettes. So I tried 9 speed and tried to filter on the 36 tooth one. 11-36 In order to really work, you'd have to choose a whole groupset. What I really want to see what could be done with a familiar frame, like Norco, and put a whole groupset on it.

So it could know that Surly has 135mm dropouts. The acid test is to go to wheels. It came up with 2 wheel sets, both 135mm dropout. But no price or merchant.

In order to use my system to build a bike, you'd pick each part according to the frame specs: It would be easiest to pick a whole groupset. Eg: Sora. I see crank, cassette, deraileur, shifters levers. R3000 of Sora drive train. R3030

  There seems to be a website called, and they refer to a site called

 - I found Surly on list.

  Choose Bar Type
  Choose Grips
  Choose A Stem
  Choose a Front Brake/Shifter

  So now I went to the second item, which is Handlebar. I chose
  FSA Adventure Compact 31.8 x 40 cm Drop Handlebar

It tells me I can buy one at Chain Reaction for 60.99 + 86.98 shipping
 - they have some concept of sending an alert if the price drops below a "set" point
 - they have 3 filters. Width: 400, 420, 440, and have the weight.