Results 1 to 8 of 8
  1. #1
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    70

    I hear and feel every hole in the rotor when braking. Is something wrong?

    Hi guys. I'm not new to disc brakes. My 2002 giant rainier had the original Avid mechanical brakes which still serve me well. I've recently purchased a 2007 Rockhopper Pro with Juicy 3 brakes and have a question.

    Before riding the bike, I ensured that the pads were flat against and equidistant from the rotors. I did that by the usual way of loosening the bolts attaching the calaper to the mount, squeezing the lever and tightening the bolts again.

    The brakes were burnt in on the road and not trail. Maybe it wasn't ideal but I did know how burnt in brakes feel so was confident that the job was done properly. On my first off road ride, I noticed that the front brakes were smoothe while the back brake sounded and felt funny. When slowing down hard, I'd feel and heard all the holes of the rotor pass through the pads. As the ride went on, I noticed it even while gently braking. The front still felt smoothe.

    I readjusted the rear brake incase it was done wrong and the situation didn't change. I removed the wheel and examined the rotors and pads. Wear (scratch marks) was even and the pads were adjusted properly. What gives? Why should this rear brake behave different from the front brake and my previous avid mechs?

    Thanks.
    Last edited by eebowler; 02-10-2007 at 10:47 PM.

  2. #2
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    47,276
    Are the rotor bolts tight? The caliper mount bolts? Hub bearings adjusted correctly?
    mtbtires.com
    The trouble with common sense is it is no longer common

  3. #3
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    70
    Not to sure about the rotor bolts but it does not shake/move while rocking the bike back and forth with my weight on it. Caliper mount bolts are secure. Hub bearings adjustment? Not too sure but there's no side to side movement at all.

    I'll go to the LBS on Mon to see what they can do but would like to solve the problem before then if possible.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    385
    my front brake (avid mechanical bb7) does that, i just figured it was the antiloc kicking in ha ha. but seriously report back if you figure it out

  5. #5
    Meh.
    Reputation: XSL_WiLL's Avatar
    Join Date
    Nov 2004
    Posts
    17,516
    Make sure the pads are hitting square. Make sure that the pads aren't sweeping across the "arms" of the rotor.

  6. #6
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    70
    XSL: You're right, the pads were too low and were bushing across the rotor arms. I added a thicker washer thingy to the IS arm from an old pair of V brake pads to raise the height of the caliper wrt the rotors.Now, the pads aren't touching the arms anymore however, the sound isn't completely gone yet. Maybe I need to make it higher or readjust the pads again but there is noticable improvement. Will post a pic on Sat.

  7. #7
    Meh.
    Reputation: XSL_WiLL's Avatar
    Join Date
    Nov 2004
    Posts
    17,516
    Check that the padss weren't unevenly worn. If they were, sand in a figure-8 pattern to resurface to flat. Or just ride them around to wear down those high spots.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Sep 2006
    Posts
    767
    Check your CPS washers for any deformity. Mine were warped due to overtightening of the mounting bolts and caused the issue you are having and an annoying squeal/vibration. I sanded down the pads, cleaned the rotor, mounted new cps washers and followed the detailed instructions in this link and it finally went away. My Juicy 5's are now super quiet and the modulation is excellent. I know how annoying disc brake problems can be. I hope this helps.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •