Rear Disc Brake Grind and High Performance Grease?- Mtbr.com
Results 1 to 8 of 8
  1. #1
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    15

    Rear Disc Brake Grind and High Performance Grease?

    Took my new mtn. Bike out to a local park on Sunday. Mostly bike paths, but some sandy trails (sandy, like beach sand). The first 12 miles was at super slow speed since I was riding alongside my Bro-in-law who's training for a marathon - avg. 7mph - to keep him company. After that, did the loop again with my wife at speeds of up to 15mph in some places. When I'm in the middle ring at mid to high gears and every gear on the big ring, I get the grinding/vibrating noise from the rear brake, but only if I'm pedalling and not if I coast. So loud and annoyingly embarrassing that I would stop pedalling whenever we got close to other people in the park (and it was crowded that day).

    I just looked up some articles for disc brake maintenance and I've seen 2 sites that mention putting High Performance Grease in the caliper housing to stop any vibrating and noises. Here's the link to one of them.

    http://www.bikemagic.com/news/articl...N/2558/v/1/sp/

    Here's the quote:
    "When fitting the brakes, dab a small bit of high-performance grease between the back of the pad and the cylinder head. This helps stop small vibrations that can cause squeal. Make sure that none of the grease touches the pad face or rotor though."

    Has anyone tried this? Can you describe exactly how to place the grease and how much? What brand of grease did you use and where do you get the stuff? I've got Avid Juicy Five Hydraulic brakes.

    I'm a few rides away from bringing my bike to the LBS for it's new bike checkup to tighten any cables from the break-in period. This is my biggest gripe on the list of items to check out. I'd like to go in with some suggestions on what I think it is instead of just dropping it off and saying it's noisy, fix it.

    My front brake suffered from pad rub initially, but it went away after a few rides. The rear brake is doing the opposite and getting worse with each ride. I guess that it could be a warped rotor that came out of the factory as well...

    Thanks,

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
    Join Date
    Nov 2004
    Posts
    17,508
    That doesn't sound like a brake issue...

    To me, it would seem like a drivetrain problem. But if it is the brakes, it's happening because of flex or because the calipers need to be centered.

    Take it to the shop.

  3. #3
    Brant-C.
    Reputation: bcaronongan's Avatar
    Join Date
    Nov 2006
    Posts
    1,062
    what kind of bike are you riding?

    take it to the shop.

    check your rear tire to see if it's rubbing the chain stays also...had a buddy that had an issue that sounds like yours.
    I just like riding my mountain bike.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    15
    It's a new 2008 Trek Fuel EX8.

    It's going back soon. i want to use it this weekend, so probably early next week.

    I forgot, here's another bit. If I ride it on grass/dirt, then go onto pavement, the grind isn't there until about a tenth of a mile or so.

    wheel flex and caliper setup must be the problem since it only happens when pedalling - or a warped rotor.

    I'll see what the wrench says next week - probably have him ride it or go out with him so he can hear it while I'm there.

  5. #5
    Brant-C.
    Reputation: bcaronongan's Avatar
    Join Date
    Nov 2006
    Posts
    1,062
    one other thing to check:
    take off the back wheel
    check to make sure the hub assembly if tight
    then put the wheel back on
    make sure the axels are seated all the way into the dropouts
    I just like riding my mountain bike.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    12
    J Lo, (let me guess, I'm the first to ever say that) check out my post begining with, "HORRIBLE". I too am having rear brake issues with my new EX8. It sounds like we are dealing with different issues, but check mine out. Are you experiencing my problem as well?

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jun 2008
    Posts
    117
    Is anyone else having this issue? I am on my 2008 EX-8 from time to time.
    Best I can tell it's because of brakes on seat stay being on the outside of the chainstay, and having some flex (very little, but enough to produce this grinding under some situations). If you notice on 2010, they move the chainstay to the outside of seatstay, possibly to address this issue. Has anyone had success in resolving this by swapping rear rotors to 160mm?

  8. #8
    Come see me after class
    Reputation:
    Join Date
    Dec 2005
    Posts
    1,431
    that is not the brakes. it is the drivetrain.

    take it to the shop.

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.