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Is bar clamp size necessary for shifters? Update   LinkCheck   Back
PartType: Shifter
DateAsked: 2020.05.23
Status: Answered

I guess the answer is NO because it is always standard for a given type of bar. All flat bar shifters would expect the "overall" bar diameter (grip area diameter) to be 22.2mm. All drop bar shifters would expect 23.8mm.

Can you tell from the bar type? Are all flat bars the same diameter? Do shifters assume a certain bar diameter, such that they don't need to specify it? For example, Shimano Tiagra Rapidfire 2x10 does not specify a bar size. So I would assume it is for a drop bar.

Diagram at Bikeman shows a drop bar being 31.8 at the "bulge" and 23.8 everywhere else.

When they say "overall width" I think they mean the diameter everywhere but the bulge. For road bars 31.8 at the bulge and 23.8 everywhere else.

Mountain Bike Bars: 25.4 and 31.8 at the bulge. 22.2 for the rest. Since that is standard, any flat bar shifter will assume a 22.2 clamp.

Design Conclusions:
 - shifter table does not need a field for bar diameter.
 - the term "grip area" is better than "overall bar diameter"

2020.05.23Not given because always determined by bar typeRobin Tivy