I recently picked up a Cannondale CAAD12 Disc and some TRP spyre disc calipers for it. Just lining up the mount holes on the spyres to the mount positions, the front disc mounts on the fork line up great. Hoever, the mount positions on the rear are closer together than the mount positions on the spyre caliper. The two spyre calipers are the same, but the disc mount positions on the rear of the CAAD12 frame are closer together.

Is there an adapter or something I need to get? Or a completely new caliper? Will this affect what size rotors I can run?

  • 1
    I vaguely suspect this might be a case of rotor-size specific flat mount disc caliper. What's the size of rear rotor? Can you measure the disctance between rear calper frame bolt holes? Commented Oct 24, 2017 at 13:46
  • @Klaster_1 brake calipers came off of another drop bar cyclocross bike. Will measure tonight. I haven't purchased rotors yet, as I was worried about this problem.
    – user21245
    Commented Oct 24, 2017 at 14:59
  • I think it should be noted somewhere, at least in this comment, for other visitors, that one can also buy the TRP Spyre, as many other disc brakes, in the flat-mount version. Commented Jun 1, 2020 at 12:07

1 Answer 1


That bike has rear flat mount. If there's room for a post mount caliper plus adapter, which from looking at some pictures I doubt there is, the rear post mount adapter of the right size is your part, something like:

TRP flat mount rear adapter

If there's no room then you need a flat mount caliper instead.

  • 2
    Thank you so much- "flat mount" vs. "post mount" were the terms I needed. I have a postmount rear that I want to fit to a flatmount rear frame. For some reason the cannondale caad12 has a post mount fork so no issue there. This website goes into painful detail, which is helpful. bikehugger.com/posts/…
    – user21245
    Commented Oct 24, 2017 at 16:47

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