I previously ran a promax 160mm rotor with a BB7 avid brake caliper. My rotor is spent and is not braking correctly. The tech suggested I used a Shimano ice-tech disk. It seems to me that, relative to the mounting surface, the braking surface of the rotor is offset a different distance and overall is slightly conical. I think this is partly supported because I cannot successfully adjust the brake caliper to gain a smooth and even brake. I am a bit upset I was recommended this part if it's incompatible with my current setup. As I sight the rotors path through the caliper, it seems that the caliper is slightly askance and does not fully contact the rotor when braking with full force. I am not sure what pictures would describe this.

Is this a known problem? Should I have purchased a different mount adaptor for the caliper to fit the new rotor?

  • Are you sure your wheel sits properly in your dropouts? IMHO the best way to ensure that is mounting (or at least tightening) the wheel with the bike upright, standing on the wheel. If you have some play in your dropouts, you might try to mount the wheel such that the brake rotor aligns best with the calipers.
    – Burki
    Commented Apr 17 at 11:11

2 Answers 2


It is normal for there to be slight variations in rotor tracks, even between rotors of the same brand. Because of the very narrow tolerances with disc brake pads, even these minor variations become significant.

Have you tried the usual trick of loosening the caliper bolts, clamping the brake, and retightening the bolts while it's clamped?

  • Yes I tried this, but no matter what I can't align the rotor and caliper. The problem is that the caliper would need to be offset to align with the rotor, but the best I can do is wedge the caliper to an extreme angle. The problem is that under braking it only contacts the pads.
    – AdamO
    Commented Apr 15 at 23:57
  • Update, after some playing around, I realize, somewhat stupidly, that I was loosening the wrong part of the caliper (rather the adaptor that meets with the frame), I now see that the other end of this on the caliper has ovalized holes. I can now get it to seat properly.
    – AdamO
    Commented Apr 19 at 15:59

Just a cumulative update on the massive amount of work this takes. I was rocking the Avid Road BB7 caliper. The BB7 pad has tabs that press inward to the wheel and interfere with the spider. After taking these off with the hacksaw and adjusting the pads, the torx head on the inner pad adjustment interfered with the spokes. In all, I've found this caliper fairly ridiculous, and I swapped it for a TRP Spyre C which is working a complete treat by comparison.

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