650 to 26" wheel compatibility?

BigSpecs

Hi. I am renovating an old road bike for my wife. it originally had steel rimmed 650 wheels on it. I want to source some new ones with alloy rims to make for safer braking. I am finding it a little tricky to get new 650's on my limited budget. What are the chances that I could use 26" mtb wheels instead? Would they fit? and would the brake callipers reach the rims?
Thanks for any help.

redddraggon

BigSpecs wrote:

Hi. I am renovating an old road bike for my wife. it originally had steel rimmed 650 wheels on it. I want to source some new ones with alloy rims to make for safer braking. I am finding it a little tricky to get new 650's on my limited budget. What are the chances that I could use 26" mtb wheels instead? Would they fit? and would the brake callipers reach the rims?
Thanks for any help.

I'd imagine the hub size would be 130mm on the 650c wheels and 135mm on the MTB wheels, so that may be a problem.

maddog 2

Sheldon lists 650c as having a 571mm bead seat diameter (or BSD)

26 inch mtb wheels are 559mm BSD

a 12mm difference, which means (all things being equal) a mtb rim will be 6mm lower than a 650c rim.

If your brakes can accomodate such a drop then it could work. You might want to fit long drop brakes to give you more adjustment (but that's more cost)

Ring Paul Hewitt, he should be able to build you some 650c wheels.

see http://sheldonbrown.com/tire-sizing.html for bumf