Results 1 to 11 of 11

Thread: Front disc brake rub

  1. #1
    MoJo Friar shotgun jeremy's Avatar
    Join Date
    Mar 2017
    Location
    Central Texas
    Posts
    135

    Front disc brake rub

    When I clamp down my front wheel, the wheel shifts just enough to rub my outer brake shoe on the rotor non-stop. It seems like there would be an easy fix, but I'm just not seeing it. I already tried clamping down with less tension. However, if I clamp it down very loosely and start finger spinning the nut, the wheel still shifts over. When sitting like this, the disk is about .005mm away from the caliper - I measured with a feeler gauge. I feel like it should be more in the range of .020-.015mm.



    Sent from my VS987 using Tapatalk

  2. #2
    MoJo Bishop AFROTHUND3R's Avatar
    Join Date
    Apr 2014
    Posts
    192
    Make sure you're setting the wheel wheels down. IE not in n a stand or with the bike upside down. If that doesn't fix it loosen the bolts on your caliper so there is a little play in the caliper. Press your brake lever, and with the lever down and the pads holding the rotor use your other hand to retighten the caliper bolts. This should realign your caliper. If that doesn't work it could be a slightly bent rotor. That's all I got.

    Sent from my SM-G900P using Tapatalk

  3. #3
    MoJo Friar shotgun jeremy's Avatar
    Join Date
    Mar 2017
    Location
    Central Texas
    Posts
    135
    I had to think about what you meant with that first sentence. Lol. That is how I first did it though - pulled it out of the truck, set the back wheel down, and lowered the forks on the axle.

    The caliper doesn't look like it has that much play around the mount bolts, but it's worth a shot! I'll try that when I get home. Thanks for the input.

    Sent from my VS987 using Tapatalk

  4. #4
    Mojo Advanced Neophyte attaboy's Avatar
    Join Date
    Jun 2009
    Location
    austin
    Posts
    116

    Front disc brake rub

    doubt it's rotor. when those bend it's not uniform. sometimes piston alignment gets off center. fix: first, remove brake pads. then you can insert an appropriately spaced wrench in between pistons and by moving wrench as a lever back and forth, gently push them all the way in. then do the above procedure to recenter rotor.
    Last edited by attaboy; 07-18-2017 at 08:22 AM.

  5. #5
    MoJo Neophyte lachrimae's Avatar
    Join Date
    Mar 2016
    Location
    Leander
    Posts
    15
    Quote Originally Posted by attaboy View Post
    gently push them all the way in
    Emphasis mine... take it from a guy who cracked a ceramic piston with his gentleness.

  6. #6
    Mojo Advanced Neophyte attaboy's Avatar
    Join Date
    Jun 2009
    Location
    austin
    Posts
    116

    Front disc brake rub

    just looked more closely and see you are running mechanical disc brakes. Unless they happen to be hybrid (mechanical pull, hydraulic caliper) then my previous post is wrong. if bb7:

  7. #7
    RoBoMoJo Kill Phil's Avatar
    Join Date
    Sep 2006
    Location
    South Austin
    Posts
    507
    Loosen caliper mount bolts. Spin wheel quickly and grab and hold the brake lever. While holding it, tighten the caliper mount bolts. This should reposition the caliper properly.

    If that doesn't work, I've positioned a flashlight on the ground so I can clearly see where the caliper needs to be positioned while slowly spinning the wheel, I loosen the caliper bolts and manually positioned the caliper where it doesn't rub. This is a pain in the ass and I haven't had to do this since I moved to a bolt through axle.

    Sent from my SM-G935V using Tapatalk
    JB Goodwin REALTORS

    If you are looking to buy, sell, or lease, I can help.

  8. #8
    MoJo Friar shotgun jeremy's Avatar
    Join Date
    Mar 2017
    Location
    Central Texas
    Posts
    135
    Thanks for the input guys. It is full mechanical. Ill play with it soon since it appears to be a quick fix.

    Sent from my VS987 using Tapatalk

  9. #9
    MoJo Friar shotgun jeremy's Avatar
    Join Date
    Mar 2017
    Location
    Central Texas
    Posts
    135
    That was a good video. I put my bike on the bench (I don't have a bike stand) released the mounting bolts, squeezed the brakes, and tightened the bolts. Still had rub. So then I tried messing with the outboard nut, but it felt real weird like I was letting spring pressure loose when I released it, so I put it back how it was. I noticed that the paint around the elongated mount holes had given away where the bolt had been tightened. Paying attention to this, I only put my bolts halfway in the fork, spun the wheel, hit the brake, and tightened them down. Voila! So I don't know if I did something when I was playing with that outboard adjustment bolt, or if letting the mount bolts clear the built up paint...but its good now.

    Thank y'all!

    Sent from my VS987 using Tapatalk

  10. #10
    MoJo Mother Superior FJsnoozer's Avatar
    Join Date
    Jul 2015
    Location
    Austin
    Posts
    1,582
    Mechanical brakes are completely different to allign and almost require adjustment each time the wheel comes off is you have a QR front.

    Only one piston moves, so you want to tighten the wheel first and then eyeball the stationary piston is perfectly aligned and close but not touching the rotor. Rotate the rotor to confirm it is not warped either.

    Do yourself a favor and source a used BB5 or BB7 mechanical caliper. You can adjust the stationary side with a dial on the side.

    Or get XT m8000s on sale at lunch hour on a Tuesday at performance bike and be done.


    Sent from my iPhone using Tapatalk

  11. #11
    MoJo Friar shotgun jeremy's Avatar
    Join Date
    Mar 2017
    Location
    Central Texas
    Posts
    135
    What causes them to so easily become misaligned every time you put your wheel back on?

    Sent from my VS987 using Tapatalk

Remove Ads

Search tags for this page (caching method: table)

There are currently no search engine referrals.
Click on a term to search our site for related topics.

Bookmarks

Posting Permissions

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