Cheeky favour for beers (testing 650b disc wheels on a road bike)

Posted on Wed 27th, September 2023

• #1

brodycorn

Has anyone had a good experience fitting 650b wheels to a road frame for bigger tyre clearance? Mine goes to 33 mm on 700c, and I was wondering if 40 mm on 650b wheels would fit.

If anyone is running that rim/tyre combo with a 12 mm thru axle and would be willing to meet and let me do a quick test fit, beers/£ would be in order!

Aware of the geo issues/pedal strike potential (total wheel diameter could be 18-20 mm less), I have 165 mm cranks so am hoping it shouldn't be too much of a problem, but would love to hear others' experiences too
• #2

j_p_

From experience I'd say it's probably not worth the faff for 7mm extra, assuming you can't squeeze a slightly bigger 700c tyre in. 650b tyres between 32 and 40mm are a bit uncommon too. If you really fancy it though the main limiting factor on a disc bike is chainstay clearance as the bulge of a 650b tyre tends not to align with the chainstay dimple. The top of a 700c rim tends to be about where the middle of a 650b tyre is, so if you measure the width there you should have a good idea what could work. Afraid I don't have anything to test with, have just looked into it before
• #3

Technics100

I had a Holdsworth Elan which would fit 700c and 28mm with guards.. I was just able to squeeze 650b and 42mm WTB Resolutes on it although it nipped the rear stays if the pressure was above 30 psi..

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