Originally Posted by
LeicaLad
I have an old 27" frame that I'd like to go to 650B on, but it may be just too far of a reach.
The photo below is that of Zeus calipers against a 700c wheel. As you can see, I'll need long reach brakes to go to 700c.
Is it silly to think of trying for 650B? Or should I just get fat 700c wheels & tires, plus, of course, long reach brakes?
Your sidepulls don't look all that long, which may be why they're adjusted to the bottom of their reach. You can figure out your current reach needed for 27" wheels, and what you will need for 650b's.
If you remove your front caliper, and measure the distance from the center of the brake hole in the fork crown to the center of the braking area of the rim, then add 23mm, as this is the rough difference of radius between the two sizes, 27" and 650B, this should give you the brake reach needed for a 650b conversion. Using a caliper to take this measurement really makes things infinitely easier.
At least this is how I determine brake reach.. I think it's correct...