Originally Posted by
robatsu
I think that is the most concise explanation of why 650B and not 26" I've seen.
Thanks!
So it seems that 650B's utility is in conversions of existing 700c/27" which can't fit wider tires, or perhaps even if you could, you don't want to raise the standover height.
It's not so much the standover height as the clearance under the brake bridge. On most 700C bikes you can't put tires beyond a certain size on the bike without either rubbing the fork or making clearance too tight for fenders.
But for going out and buying a new dedicated bike, sized to fit and all, is there any benefit to buying a dedicated 650B rather than a 700c designed to fit wider tires (and fit the owner as well).
As far as I can tell the only real difference is that to design a 700C bike to have the same clearance and wide tires, you end up with a very tall fork and associated frame geometry. You are limited to the same brake selection as 650B would use because there are only so many long reach brakes today. You slightly lower rolling resistance than 650B. What you don't have is as desirable a frame geometry because of the accommodations made for tires and fenders and the tall fork/rear triangle. I think that's what it comes down to. With 650B you can have nice frame geometry, just like a normal 700C bike and still maintain a cushier ride and fenders.
Karl