Join Date: Apr 2006
Location: Ithaca, NY
Bikes: 1980 Mercian Olympic, 2004 Spectrum Ti custom, 2007 Bob Brown fully lugged steel tandem with S and S coupling and DaVinci ICS
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Good troubleshooting suggestions!
Originally Posted by sheba
The problem probably has nothing to do with you QR skewer. Is your BB7 caliper set pretty tight before the ride? Is it rubbing slightly before the ride? This may cause it to heat up and expand.
Have you tried simply switching the front and rear caliper and test riding it out for a while? Might be worth it too.
What about your cables and housing. Are they the proper length? Is the rear cable tightening when you turn the bars because the housing is too short? Is the adjustment screw on the brake lever loose? Are your cables lubed good?
What about the disc. Is it warped at all? Is it the standard 6 bolt mount or do you have one of the Chris King rotor adapters?
What kind of brake pads are you using? Sintered-metal or organic compound?
The BB7 caliper is 4 clicks from contacting the rotor - so free and clear. I don't think there is any friction or rubbing slightly. If it were heating up and expanding I would expect that when it cooled down would no longer contact the rotor. In fact, the rotor is tightly clasped on the rotor and it happens relatively fast, I back the adjustment red nob off another 4 clicks so it is free and then it happens again. I don't need to tighten it 8 clicks when I ride another day - it is permanently tighter. Strange.
I don't have a front caliper - I have regular side pool brake on the front. I might consider purchasing another BB7.
The cables are fine - this has happened since the bicycle was brand new and Bob Brown set it up himself - very carefully.
Standard 6 bolt mount for the rotor. The rotor is true. I have had a outstanding local bike mechanic look at it and he thinks the set up is fine. It is a difficult problem to reproduce in his shop - especially during the busy Summer months.
I am using the standard pads that came with the BB7s. Should I try something else?
I appreciate your suggestions.