shelbyfv

I have acquired a really nice 1994 RB-2 in the plum color. I had in mind using it for rail-trails, but I find it will only take 28mm tires and even those rub on the fork crown unless I am careful of the pressure. At any rate, not enough clearance for gravel, IMO. I have considered a 650b conversion and the measurements seem to make it a good candidate with one exception. The brake drop will require the really long 70mm calipers and I don't know how those will work. I use the medium long reach on my Gunnar Sport and they are not as nice as the Ultegra on another bike. Another thought is to build 700 wheels with a wider rim, like the Velocity synergy, which might make the 28s wider rather than taller. Any thoughts on either of these options? thanks!

khatfull

As long as you use good pads I don't see what the issue would be? Any modern, nice dual-pivot caliper (Tektro, Shimano, etc.) will have all the power you need.

shelbyfv

I use Kool Stop salmon on the Tektros and they stop well enough but seem less "crisp" than the Ultegras. I guess I am concerned that even longer arms would exacerbate that to the point it would annoy me. On the other hand, the bike would then be useful.....

positron

I cant understand how the 28mm tire is rubbing on the fork crown while at the same time you need the max 70mm brake drop.... Unless the RB2 originally had 27" wheels?

either way, the tektro long reach brakes work very well.

shelbyfv

The 70mm drop is if I go to 650b. The current brakes, with 700 wheels are short reach. The steerer tube extends below the rest of the fork crown by about 4mm. I considered using the Dremel but don't think that alone would give me enough clearance. Thanks for the info about the brakes.

tomio

I don't imagine the 94 being much different from the 91, but my 91 can take 28mm no problem.

If your housing ends are finished and they are of adequate length, I can't imagine noticing a huge different between dual pivots. Even 70mm dual pivots are really strong if adjusted correctly.

JunkYardBike

Yeah, doesn't make sense to me either. I had a late 80's RB-2 that fit 28s fine. In fact, 1994 is considered the apex of the Grant Petersen era at Bridgestone (also his last year I think), and he was a big proponent of fat tires. Here's the catalog page for the RB-1, which had the same geometry, claiming it has room for 32c tires: https://www.sheldonbrown.com/bridgest...4/pages/45.htm

Are you sure your tires are true 28s?

shelbyfv

I'll pump up the tires and measure them. They are Paselas. There is plenty of room except at the fork crown.