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Rear disc brake

dinyulldinyull Posts: 2,962
edited November 2017 in Workshop
I changed the pads and disc on the rear of my commuter this weekend. What should have been a 5 minute job turned into at least 3 hours - which always seems to be the case when I have to fettle with the rear brake.

Brakes are TRP Spyre (mechanical) and I can never get the rear setup without any rub.

1st problem this weekend was...when I replaced pads and disc, the was no clearance between the 2 meaning the wheel wouldn't turn. This was with the pad adjustment wound all the way out on both sides and cable disconnected.

To get around this I had to swap front and rear pads - front pads were worn down enough so there was some clearance.

Still, once this was done and cable inner replaced etc I still get some play in the brake lever - when I pull the brake the cable doesn't spring back all the way - which causes a rattle. I'm thinking this would be resolved by replacing the outer cable too? Although I've had this problem from the day I fitted them new...

Also, I have lots of lever travel (front and rear) and if I screw out the barrel adjuster to tighten things up pads/discs start to rub anywhere near before levers feel tight.

I'm a fairly competent home mechanic, building up a few bikes now without any problems, but always seem to have problems with discs - to the point (and I've said this before) I'm close to getting rid of the bike and go back commuting on caliper brakes.

Are mechanical disc always a PITA? Or what am I doing wrong?


  • zefszefs Posts: 484
    Seems like you are doing something wrong. TRP spyre's are really easy to adjust in my case but you already mention you used the 3mm adjustment for pad clearance. Is the caliper aligned correctly? What is the rest of your setup (bike/rotors/pads), a photo might help.
  • dinyulldinyull Posts: 2,962
    Right, I'll go through how I set them up:

    Loosen caliper bolts.
    Pull brake lever to centre caliper on disc, and whilst pulling lever tighten up caliper bolts.
    Adjust each pad to suit.

    After reading through my post again, I'm convinced it's the outer that's the problem. I pull the rear brake and the cable/caliper doesn't spring back to the original position meaning the brake rubs.

    I also spotted another post on here yesterday about servicing the TRP Spyre calipers, so will give that a go too and hopefully get sorted.

    Still doesn't solve the problem of not enough clearance for new pads...
  • zefszefs Posts: 484
    Yes sounds like a cable issue. Why not take it to LBS to sort it out?
    Did you get compatible pads? (m515,525), although not sure if there are pads with more material to them.
  • dinyulldinyull Posts: 2,962
    Yep, M515.

    Actually, looking at this - ... uild-guide - seems quite a common problem and might not be cable related.
  • zefszefs Posts: 484
    He was using the older version which got recalled, do you use the new ones? Might as well contact TRP describing the issue.
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