Bicycle Mechanics - wheel conversions

Bear with me for a potentially stupid question. Theoretically, given a typical vintage road bike with a steel frame, sidepull brakes, friction shifting, and 700c wheels, *exactly* why couldn't you put 26" wheels on it?

By 26" wheels, I mean 559 mm mountain bike sized, not 650B or 650c wheels. I can see a problem with brake reach, but that could be solved with extra-long brake calipers. Is there a problem with the spacing of the dropouts? Where, exactly, are the incompatibilities?

The problem would lie in the bottom bracket height. You would be shortening the height of your pedals from the ground because of the smaller wheels, which may give you problems with pedal strike.

The bike in question has 65mm cranks. It's actually one reason why I bought it in the first place. One objective for getting smaller wheels is to lower the effective top tube height, since I am a small person.

That would be some pretty serious reach on those extra-long brake calipers.

Dropout spacing is not a huge problem on a steel bike. Some hubs are easy to respace, also.

BB height could be an issue. I have converted one bike from 27" to 26" and BB height was a tad low, but reasonable. I replaced the front fork with a MTB one, so the front brake studs lined up right. And the rear was an internal rum brake, so that was not an issue.

jim

The bike in question has 65mm cranks. It's actually one reason why I bought it in the first place. One objective for getting smaller wheels is to lower the effective top tube height, since I am a small person.

Unless you are married to this bike, I think that is really an expensive/problematic solution to a basic and simple problem: you have the wrong bike.

jim

You're right. But since that solution (a new bike, likely a women's specific model) is equally expensive and therefore problematic, I thought it was worth entertaining more...creative...solutions.


Unless you are married to this bike, I think that is really an expensive/problematic solution to a basic and simple problem: you have the wrong bike.

jim

I am all for cobbling together creative solutions, but I think this one will not work out well for you.

I admire the spirit though.

jim

You would need a brake reach about 32 mm LONGER than you have now and finding brakes with that much extra reach will be difficult.

If the frame with the new wheels fits you really well then it may be worth having a set of canti posts brazed onto the seat stays and get a fork with canti stays on it.

On the other hand an old school "racing" mountain bike set up with narrow wheel rims and a 26x1 tire or 650 rims with skinny tri tires would be a nice option.

I remember how Rivendell makes their smaller sizes for 26/650 wheels just for the reason that in the smaller sizes the overall bike just looks and fits better.

The tires that would normally go on a 26" rim would be too fit in some road bike frames or forks.

Al

[QUOTE=BCRider;6462355]On the other hand an old school "racing" mountain bike set up with narrow wheel rims and a 26x1 tire or 650 rims with skinny tri tires would be a nice option.
QUOTE]

This is my vote. Such bikes are common and cheap. I ride one like it myself, and it is shockingly nimble.

jim