Originally Posted by
Longfemur
There are people who have a special affection for 650B bikes. It's a taste, somewhat of a refined one that you can only appreciate if you have it. More than that, it's a tradition, like tweed sports jackets and pipes. I would love a 650B wheeled bike myself, if only because at 5'3", my frames are always a little small for 700C wheels.
Converting a 700C bike to 650B is pretty easy if you have the right frame to start with.
The best frames for conversion are steel criterium racers. Steel because the stays are thin enough to allow for the fat tires to fit. And the criterium geometry has a high BB that works well with the slightly smaller 650B tires. Crit bikes usually had 700C wheels and short reach brakes and that too plays into the 650B wheel size. You can use the new Tektro R556 brakes: they reach down to the 650B rims just fine.
We make a fork that replaces the fork on a crit bike. It has more offset (read lower trail) and it has fender eyelets and rack eyelets.
If you shop around, you can put together a nice 650B bike for not a lot of money.
Lot's of modern racing bikes work too. Entry level aluminum bikes. You just have to check the clearance between the chain stays. Our conversion fork works well with those frames too.