Bb7 Rotor Hits The Caliper

[Scoox]

I have a similar problem and I'd like to hear your tips/views. I bought a BB7 with a +20mm adapter and an Avid 185mm rotor. I also have an Echo TR disc brake and corresponding 180mm Echo TR rotor for testing.

(Fork, Brake, Disc - Result)

SL, Echo, 180 - Perfec fit, original configuration. Suggests mounts are well positioned...

SL, Echo, 185 - (Not tested)

SL, Avid, 180 - Rotor close to caliper

SL, Avid, 185 - Rotor rubs calliper so hard that wheel cannot turn

Urban, Echo, 180 - (Not tested)

Urban, Echo, 185 - (Not tested)

Urban, Avid, 180 - Almost perfect fit and no rubbing

Urban, Avid, 185 - A smaller rotor would fit better, pads hit rotor arms no rubbing though

(I wanted to do a pretty table but the forum seems to trim consecutive whitespace characters...)

The original configuration SL fork + TR brake + 180mm rotor has no problems. I am assuming that all ISO mounts are the same here, therefore I expect the Avid brake with the 20mm adapter to fit.

So I am just curious as to whether this is a problem with the the forks or the brakes. The BB7 brake works with the SL forks but not the Urban forks; since both forks being made by the same company, it's got to be a problem with the mounts not being welded in the right place.

Popping on some washers will do the trick, it's just that common sense tells me that NOT using washers (and NOT using adapters for that matter) results in the stiffest possible set-up. I could also try a slightly smaller after-market rotor. The Echo rotor fits well in terms of size but is unsuitable because it is designed for wider pads (with BB7 pads you are pretty much braking on the rotor holes).

Edited April 7, 2012 by Scoox