I just built a mountain bike with Avid BB7 brakes and Shimano V-brake levers. I used the exact same configuration on another bike, and it worked beautifully. But on this one, the brakes are just weak as hell. I know that disk brakes are supposed to have a short break-in period, but I'm way beyond that now, and still no change. What's going on and how can I fix it?

  • 1
    Are they properly adjusted and mounted? What pads and rotors are being used? We need more details. May 12, 2013 at 14:59
  • Make sure you purchased long-pull BB7 calipers and not the short-pull versions specific for road bikes!
    – WTHarper
    May 12, 2013 at 16:00
  • sram.com/avid/family/bb ... You can see there are quite a few versions.
    – WTHarper
    May 12, 2013 at 16:01
  • Yes, I have the long-pull MTB version. Rotors: 160 rear, 180 front. I'm using the pads that came with the brakes. May 12, 2013 at 16:14
  • how much time did you have to break them in?
    – trailmax
    May 13, 2013 at 9:02

1 Answer 1


Avid recommends breaking those discs and pads in with about 30 or 40 deliberately hard stops in order to build up a good foundation. If you've gone through that process a couple of times and still no dice, there could be brake fluid on the discs or pads. Some water or isopropyl alcohol should take care of that.

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    BB7s are mechanical discs.
    – WTHarper
    May 12, 2013 at 21:09
  • Oh that's right, forget the part about bleeding. May 12, 2013 at 21:24
  • Just to add to the answer, all manufacturers recommend bedding in disc brakes. This transfers some pad material to the rotors. It improves braking substantially. I don't exactly know the chemistry and physics behind this, but you need to bed in every disc brake at every level, from Tiagra to Dura Ace on the road.
    – Weiwen Ng
    Sep 11, 2020 at 12:44

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