warbling brakes- Mtbr.com
Results 1 to 37 of 37

Thread: warbling brakes

  1. #1
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90

    warbling brakes

    The brakes on my EVO are warbling. I don't know how else to describe it. When braking with any sort of authority they make a bunch of noise down at the pads (both front and rear). It doesn't happen during a gradual or easy slowdown, only when using them aggressively. Any way to get rid of it? I don't think it's causing any brake performance problem but since it's done this since new I'm not sure. I don't have much to compare it to. My last bike had mechanical disk brakes that performed well and never made this kind of noise.

  2. #2
    mtbr member
    Reputation: s0ul_chicken's Avatar
    Join Date
    Aug 2013
    Posts
    1,767
    It could be possible pad contamination, and what you can try do to fix it is easy. First off, I would remove the brake pads, and give them a light sanding with an alcohol wipe-off after. Same with the rotors, a light sanding and cleaning followed by a proper bedding-in of the brake pads. Also be sure all of the bolts are tight that hold the caliper, a loose connection can cause vibration which translates into noise. Good luck!

  3. #3
    mtbr member
    Reputation: toddre's Avatar
    Join Date
    Mar 2004
    Posts
    2,389
    Wow. Very rarely do u hear of a non Avid brakes making noise.
    What Soul said, clean and tighten everything. I had the same issue with some NOB Avid XOs, tried everything. As a last resort I swapped to after market pads and quiet rides. never looked back. Good luck!

  4. #4
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    What grit sandpaper should I use? And does it matter what it's made of? (aluminum oxide ok?) Same on both pads & rotors? Going to try it today, will report back.

  5. #5
    755872
    Guest
    I use pretty fine grit (200 on the pads, 400 on the rotors) and aluminum oxide should work fine. I use a spray bottle loaded with denatured alcohol, soak things down good and then let them air dry. Keep you fingers off the pads and rotors (wear gloves). Burn in after cleaning is pretty straight forward, pinkbike has a good article on it.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jun 2014
    Posts
    270
    I would question sanding the rotors, and would use at least a 600 grit wet/dry paper if you do. Another thing I would try first is adjusting the calipers to center them on your rotors. There are two screws that clamp the caliper to the stationary block. Loosen them, then move the caliper to center, then retighten. You might need to apply the brakes while loose to center the pads in the caliper. Check for a youtube video for more details. This helped the noise on my bike a lot. Didn't completely cure it, though (I have Avids).

  7. #7
    mtbr member
    Reputation: s0ul_chicken's Avatar
    Join Date
    Aug 2013
    Posts
    1,767
    There are a few companies that make rotor/caliper adjustment tools, makes it simple to center your brake pads. I picked up a Super B for two bucks, and I should have bought one a long time ago.

    warbling brakes-capture.jpg

  8. #8
    mtbr member
    Reputation: watts888's Avatar
    Join Date
    Oct 2012
    Posts
    6,277
    I'll second adjusting the brake alignment. If you're causing flex in the rotor under heavy breaking, it's probably picking up some sort of harmonic oscillation. If you don't cause the rotor to twist, look towards sanding the rotor.

    And, as always

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    I didn't sand or disassemble anything yet. I have some more information. It seems to only be the front brakes. I watched under heavy braking and the whole fork is vibrating forwards to backwards during this time. I hold constant heavy pressure which starts to slow the bike, but looking at the fork it looks like the brakes work and then let loose, then work again and let loose, very very quickly, which causes the fork to vibrate front to back under heavy braking. I did loosen the caliper bolts, squeeze the brakes to center it, and then re-tighten. Didn't seem to make a difference. I am hesitant to sand anything as these are close to new (not many miles on them, may be a hundred or so). They've been doing it since new although I didn't realize what it was doing to the fork during the noise.

    I also cleaned the rotors with auto brake cleaner and some new rags. Not sure whether that is the right chemical but it also didn't seem to make a difference.

    It looks to me like there are two separate sets of mounting bolts on the fork. First, directly connected to the fork is some sort of bracket, and then the caliper is mounted to the bracket. Interesting thing is that I can't loosen the bracket without completely removing the caliper since one of the bolts is directly underneath the caliper. Also, there appear to be tiny set screws or something (with a red thread locker on them) which sort of look like they are supposed to hold the mounting bolts in place but in fact the mounting bolts were pretty easy to remove.

    Also, I wouldn't necessarily mind taking this to a shop to get it looked at but the local shops around here are absolutely terrible (which is why I got the airborne to begin with!).

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    Here are the photos. Are those tiny allen head screws with the red thread locker really supposed to lock in the mounting bolts or are they something else?
    Attached Thumbnails Attached Thumbnails warbling brakes-fullsizerender.jpg  

    warbling brakes-fullsizerender-1.jpg  


  11. #11
    mtbr member
    Reputation:
    Join Date
    Oct 2007
    Posts
    1,546
    A light sanding isn't going to hurt those pads. Lay your sandpaper on a flat surface, do a couple figure 8's with the pads just to get the glaze off. Replace and ride.
    Loosen just the caliper, no need to loosen the adapter on the fork. Squeeze the lever and retighten the caliper.
    Oldest daughter doesn't ride.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    I'll try it. How to get the pads off?

  13. #13
    mtbr member
    Reputation:
    Join Date
    Jul 2015
    Posts
    26
    Have you checked to make sure your rotor is true? Sounds like it might have a minor bend if it's grabbing and then loosening and then grabbing again and causing vibrations?

  14. #14
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    I did, I don't think it's warped. It doesn't rub while free spinning and in any case I think the rotors are flexible enough that if it did have a minor warp, it wouldn't affect the braking in this way.

  15. #15
    mtbr member
    Reputation: watts888's Avatar
    Join Date
    Oct 2012
    Posts
    6,277
    Quote Originally Posted by saberworks View Post
    Here are the photos. Are those tiny allen head screws with the red thread locker really supposed to lock in the mounting bolts or are they something else?
    It looks like they're supposed to lock down the bolts. Since the area they clamp to is above the threaded section (or at least the threaded section that actually threads into anything), I'd use them. Probably wait till the other problems are hashed out first.

    Sanding the pads as suggested work fine. Spray a litle carb cleaner/brake cleaner on them just to "rinse" them off afterwards and they should be good.

    I had similar issues with a cheap rotor once where it wasn't smooth. The thickness of the rotor varied. It was really cheap, like mongoose cheap. I could look at the rotor and actually see the areas where the brake pads would catch and then let go. If you see waves on the rotors surface, might have something similar. If you feel real strongly about these rotors, I've actually had good luck with the chinese knockoff avid rotors on amazon. $8 for 2 160mm rotors and bolts. Once they bed in, they've worked great.

  16. #16
    755872
    Guest
    Those allens probably have counterparts on the opposite side. Hayes doesn't use them much and they're not in the current online manual. Likely another device to lock the calipers in place after the bolts are tightened, not affecting your noise. Warped rotors can cause a chirp when you're riding. Not a big issue but it can be annoying. Warble/squeal under braking is normally contaminated pads/rotors or improperly broken in pads/rotors (sufficiently addressed above). Pads may not be cleanable enough to eliminate warbling. I've been down the cleaner/sander path and if they have oil in them that you can't get out, they're toast. Organic pads can be quieter, but less powerful (esp if your heavy).

  17. #17
    mtbr member
    Reputation:
    Join Date
    Jul 2014
    Posts
    4
    The tiny allen screws are for caliper alignment. The correct method to center the rotor is to push the caliper so the brake pad rubs on the outside and back the caliper off of the rotor with those screws.

    If the pads are not rubbing you don't need to touch these.

  18. #18
    mtbr member
    Reputation: pattongb's Avatar
    Join Date
    Jun 2011
    Posts
    741
    Quote Originally Posted by saberworks View Post
    The brakes on my EVO are warbling. I don't know how else to describe it. When braking with any sort of authority they make a bunch of noise down at the pads (both front and rear). It doesn't happen during a gradual or easy slowdown, only when using them aggressively. Any way to get rid of it? I don't think it's causing any brake performance problem but since it's done this since new I'm not sure. I don't have much to compare it to. My last bike had mechanical disk brakes that performed well and never made this kind of noise.
    Ive had the exact same problem ever since I got my EVO. Been the one drawback of the online order process compared to a shop. Finally had a friend come look at the front brake and he said the rotor was warped. He straightened it as best he could and the front tire spins much better now; however, there is still a high pitched hum when the tire rotates emitting from the front brake, so obviously its still not 100%.

    Just do what im about to do, pony up the money and take it to a local shop...
    People ask me all the time "who beat you up"? I tell them "a tree". They just look at me funny....

  19. #19
    mtbr member
    Reputation:
    Join Date
    Jun 2009
    Posts
    71
    You guys may benefit from getting aftermarket pads. The brakes on my Goblin were noisy until I replaced them with different pads and all is well now. I don't mind some noises on the bike but noisy/gobbling brakes is where I draw the line!

  20. #20
    mtbr member
    Reputation: toddre's Avatar
    Join Date
    Mar 2004
    Posts
    2,389
    Quote Originally Posted by megalowmatt View Post
    You guys may benefit from getting aftermarket pads. The brakes on my Goblin were noisy until I replaced them with different pads and all is well now. I don't mind some noises on the bike but noisy/gobbling brakes is where I draw the line!
    That's what I said earlier. EBC gold pads and be done with it

  21. #21
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    Thanks. Yeah the reason I bought airborne in the first place is because no local shop is even halfway decent and I wouldn't trust them to even install a new seat on my bike! I haven't gotten around to trying the sanding of the pads, but that's what I'm going to do first, and if it doesn't help I'll buy new ones. I just need to find some time and then learn how to disassemble these things. I've replaced rotors/calipers/pads/etc. on dozens of vehicles but never a bike! I'll report back when I have time to do it. We are planning on doing mckenzie river trail in Oregon in August so I need to get things dialed before then.

  22. #22
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    Finally got some time to do this; took way less time than I thought.

    Step 1. Remove the caliper (2 bolts) (UPDATE: you don't need to do this step!)
    Step 2. Remove the bolt holding the pads and spring clip in
    Step 3. Pull out the spring clip
    Step 4. Pull out the pads

    Installation is reverse, totally easy.

    I sanded the pads with 400 grit sandpaper. There was a glossy glaze on them for sure. After reassembling I went to bed them in and they seemed a lot better for the first few stops, but after that they were back to making the noise again

    I'm going to buy some aftermarket pads. Disappointed.
    Last edited by saberworks; 07-27-2015 at 09:52 AM.

  23. #23
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    Anyone have a link to some good pads that will fit? I can't find the EBC ones online, they say they only fit Pro & Expert, no mention of "Comp" -- does the whole "prime" line use identical pads?

  24. #24
    mtbr member
    Reputation:
    Join Date
    Sep 2014
    Posts
    14
    Where did you order that from? I found it on ebay but it's about $8 with shipping. The Hayes tool is $15

    Quote Originally Posted by s0ul_chicken View Post
    There are a few companies that make rotor/caliper adjustment tools, makes it simple to center your brake pads. I picked up a Super B for two bucks, and I should have bought one a long time ago.

    Click image for larger version. 

Name:	Capture.JPG 
Views:	127 
Size:	48.0 KB 
ID:	999348

  25. #25
    mtbr member
    Reputation: BigDaddyFlyer's Avatar
    Join Date
    Apr 2010
    Posts
    1,836
    Quote Originally Posted by saberworks View Post
    Anyone have a link to some good pads that will fit? I can't find the EBC ones online, they say they only fit Pro & Expert, no mention of "Comp" -- does the whole "prime" line use identical pads?
    I *think* the Comp takes the same pads. To verify, I'd recommend to shoot the guys at Hayes Customer Service a quick email and ask them. They've always been helpful and quick to answer emails from consumers (as far as my experience goes).

    Jeremy
    Please Note: I no longer work for Airborne. If you have an Airborne question or problem please contact them directly.

  26. #26
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    Thanks, I emailed them. I'll post up when I hear back.

  27. #27
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    They replied right away and let me know that the pads for the Comp are the same as the Pro and Expert. They are also sending some new pads for me to try!! I will report back on how it goes. Thanks again everyone for your help.

  28. #28
    mtbr member
    Reputation: BigDaddyFlyer's Avatar
    Join Date
    Apr 2010
    Posts
    1,836
    Glad it worked out!

    Jeremy
    Please Note: I no longer work for Airborne. If you have an Airborne question or problem please contact them directly.

  29. #29
    mtbr member
    Reputation: toddre's Avatar
    Join Date
    Mar 2004
    Posts
    2,389
    It's so awsome to hear about great customer service from companies...let us know how they work out

  30. #30
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    I got the pads installed yesterday. Instructions stated to use isopropyl alcohol only, and not disc brake cleaner (which is what I had used previously). I did that. Braking performance is much improved and the noise is almost gone (but not completely gone). I did bed them according to various posts. The noise I hear now sounds almost like someone is trying to use my spokes as a musical instrument, and it only happens under aggressive braking. I'm going to leave it as is for a few rides and see how it goes. The new pads are a different composition apparently and they really bite a lot harder. I'm guessing will wear out faster or wear the rotors out faster (but I don't care!). It rained here finally and I hit a wet patch as I was bedding them and accidentally locked up the front tire... glad I didn't go down

    Oh, and my previous instructions on how to get the pads out are wrong. Really the only thing you need to do is remove the pad retention screw, then the pads come right out. You don't have to remove the caliper from the bike.

  31. #31
    755872
    Guest
    Are you sure you don't need your spokes retensioned?

  32. #32
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    No, I'm not sure. The bike is pretty much brand new, I've only ridden it maybe 50 miles. After I assembled it I took it to a (semi-) local bike shop and had it gone over to make sure I didn't mess anything up, and the mechanic did test the spoke tension somehow and said it was good.

  33. #33
    mtbr member
    Reputation: s0ul_chicken's Avatar
    Join Date
    Aug 2013
    Posts
    1,767
    Quote Originally Posted by saberworks View Post
    No, I'm not sure. The bike is pretty much brand new, I've only ridden it maybe 50 miles. After I assembled it I took it to a (semi-) local bike shop and had it gone over to make sure I didn't mess anything up, and the mechanic did test the spoke tension somehow and said it was good.
    What you could be hearing is the arms of the rotor - I have heard this as well when I have had my caliper too close to one side.

  34. #34
    mtbr member
    Reputation: toddre's Avatar
    Join Date
    Mar 2004
    Posts
    2,389
    Quote Originally Posted by s0ul_chicken View Post
    What you could be hearing is the arms of the rotor - I have heard this as well when I have had my caliper too close to one side.
    I agree..... I've sometimes come across bikes where the brake is just close enough to hit a spoke u der certain riding torques. ...... check that out on your bike

  35. #35
    mtbr member
    Reputation:
    Join Date
    Jan 2014
    Posts
    90
    How to inspect for this, and how to correct it? I have adjusted the caliper by loosening the mounting bolts, depressing the lever, and then tightening them. Once I let off the lever, they open enough to just not rub, and the wheel spins freely. I have had warped rotors before which would cause them to rub even after adjusting the caliper like this. It was easily visible by rotating the wheel while watching the rotor inside the caliper. My bike now doesn't exhibit this. I also ensured that the rotor bolts were not loose.

    Thanks again for all the help!

  36. #36
    mtbr member
    Reputation: pattongb's Avatar
    Join Date
    Jun 2011
    Posts
    741
    Finally broke down and took my bike to a local shop. $35 to be told the front rotor is bent. They cannot completely straighten it and it must be replaced. That means 1 of 2 things: Either Airborne bent it during assembly of the wheel, or it was bent when it arrived at Airborne and Hayes sent them a bum rotor.

    It was not damaged in shipping as the box was in pristine condition when it arrived. I also did not damage the rotor as it has rubbed since the day the bike arrived and was assembled with tender loving care.

    I have contacted Hayes and am hoping they will replace the rotor, however I could see how they could claim that Airborne is more culpable since its much more likely the part was damaged after being taken out of original packaging.

    I'll let you know what Hayes says....
    People ask me all the time "who beat you up"? I tell them "a tree". They just look at me funny....

  37. #37
    mtbr member
    Reputation: toddre's Avatar
    Join Date
    Mar 2004
    Posts
    2,389
    Quote Originally Posted by pattongb View Post
    Finally broke down and took my bike to a local shop. $35 to be told the front rotor is bent. They cannot completely straighten it and it must be replaced. That means 1 of 2 things: Either Airborne bent it during assembly of the wheel, or it was bent when it arrived at Airborne and Hayes sent them a bum rotor.

    It was not damaged in shipping as the box was in pristine condition when it arrived. I also did not damage the rotor as it has rubbed since the day the bike arrived and was assembled with tender loving care.

    I have contacted Hayes and am hoping they will replace the rotor, however I could see how they could claim that Airborne is more culpable since its much more likely the part was damaged after being taken out of original packaging.

    I'll let you know what Hayes says....
    $35 for them to say you need a new rotor??? Holy crapsicle.
    Every rotor warps at some point. In a perfect world you'd replace them but who has that kind of cash.
    I would bet with a bit of patience you can get it pretty damn straight using an adjustable wrench or two

    Good luck!

Similar Threads

  1. Replies: 16
    Last Post: 11-16-2014, 02:10 PM
  2. Replies: 1
    Last Post: 08-08-2013, 07:09 PM
  3. Replies: 0
    Last Post: 07-25-2013, 08:14 PM
  4. Warbling Brakes
    By JonathanGennick in forum Brake Time
    Replies: 4
    Last Post: 06-02-2012, 05:07 AM
  5. Replies: 10
    Last Post: 06-16-2011, 12:09 PM

Members who have read this thread: 2

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.