Originally Posted by
Gyfte
I don't know what could go wrong with putting on 650B wheels.
The intention is to put thicker tyres on them.
So the diameter will not be much different from 700c wheels.
or am i missing something
With the Grail, it's not that you
can't run 650b, it's that there's no advantage to running 650b. You can, but you'll still be limited to the same tire size as what would fit on 700c. (42mm)
This is usually a result of the shape of the chain stays - some bikes don't have stays that immediately flare out (or may even slightly narrow in an hourglass shape), so the clearance doesn't change between 700c and 650b.