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  1. #1
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    Unfixable? Ongoing braking vibration is driving me crazy

    Ok I have elixir CR's, Reba SL 29. And my fav mechanic says the problem is fork flex, disc brakes are so powerfully and the sanctions?(sp) or parts of the fork on 29'er forks are not built up enough. He says it's worse for heavier riders (I'm 200lbs)

    My problem is simple: when braking on the front, i can feel a crazy vibration/grinding. i can see the caliper visibly vibrating. I have swapped calipers, used organic pads, bleed them multiple times, tried different rotors and rotor sizes, adjusted and readjusted the front brake... I can recreate the problem super easy anywhere, like on 6 feet of pavement right in front of bike shop. I just brake hard, anyone can see/hear the problem and it's plain for me to feel.

    So... What the heck? I can kinda ignore it sometimes but really it's SUPER annoying and doesn't happen friends I know. I really, really want a fix.

    Different fork? Headset? Roll mechanicals? I love riding but hate grinding to a stop all the time :-)

    Please Please help....Thanks!

    Oh and I feel pretty comfortable saying this is not just a "elixir cr's suck" problem. Although they do get a bad rap from some (and rightly so to some extent) tons of prople have great luck with them. I have spent hours working on these brakes tiring to fix the grinding with adjustments. I really feel that if you spend the time to bleed them right, and align the calipers they don't exhibit most of the issues people complain of.

  2. #2
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    I know this will seem far fetched, but just try it.
    1. Take the pads out, and lay them on a flat piece of sand paper on a flat surface. Sand the pads down a little so they are flat.
    2. Time the rotor off the bike, and also lay flat. Take a metal file and gently stroke the file across the pad area on the rotor all the way around. DO this on both sides. You may notice that along the top edge of the rotor you have a small lip, if so try to file this so its gone.
    3. Check that the pads arent sitting to low and not making full contact with the braking surface. See Photo 1. The pads were sitting to low, and trying to brake in the lower part of the braking surface, which is not where they should be. ultimately it moved them up (pic 3) . I know its hard to see but it did.

    I know some will think Im crazy, but I have found that on my rotors, periodically I have to do this, not because of noise, but because of the vibration, just as you have stated. You can also slightly sand the rotors to bring back some of the roughness to them, and break the glaze on them. Recently I read somewhere on this board about the height issue of the pads, and have now corrected it by placing a washer under the CPS stack on the caliper mount(pic 2). Upon last ride, no noise, vibration, etc.

    Hope this helps.
    Attached Thumbnails Attached Thumbnails Unfixable? Ongoing braking vibration is driving me crazy-picture-011.jpg  

    Unfixable? Ongoing braking vibration is driving me crazy-picture-012.jpg  

    Unfixable? Ongoing braking vibration is driving me crazy-picture-014.jpg  

    Last edited by nov0798; 02-11-2012 at 09:27 PM.

  3. #3
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    Quote Originally Posted by slat3dx View Post
    Oh and I feel pretty comfortable saying this is not just a "elixir cr's suck" problem. Although they do get a bad rap from some (and rightly so to some extent) tons of prople have great luck with them. I have spent hours working on these brakes tiring to fix the grinding with adjustments. I really feel that if you spend the time to bleed them right, and align the calipers they don't exhibit most of the issues people complain of.
    I, and many others, have been through this before. I don't know anyone that narrowed the problem down to being the fork. Most bought a set of Shimano/Magura/Hope brakes and never had a problem again.

    It's an issue of resonant vibration frequency. Avid brakes just seem to be less stiff in their mounting than others(CPS washers maybe?). There are some frame/wheel or fork/wheel combinations that vibrate at a frequency which the Avid's excite.

  4. #4
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    I had also a very extrem vibration problem with my hayes stroker trail with original pads. Switched to the green swissstop and voila no rubbing, squealing vibrating or else. Better than the orginal pads.

    Unfortunately I don't know if they are avaible in the us (I'm from germany). Many people here use them with their brakes.

  5. #5
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    I have done the sanding the pads already but not the filing the rotor. Thanks for the tip! I'll try following your instructions and let you know.

  6. #6
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    Thanks! Its true I have only tried Avid brand organic & metallic pads. I had not heard of swisstop but I have also been recommended to try koolstop. It looks like the swisstop are 40$ usd. for one pair... pretty steep :-(

  7. #7
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    Quote Originally Posted by car_nut View Post
    I, and many others, have been through this before. I don't know anyone that narrowed the problem down to being the fork. Most bought a set of Shimano/Magura/Hope brakes and never had a problem again.

    It's an issue of resonant vibration frequency. Avid brakes just seem to be less stiff in their mounting than others(CPS washers maybe?). There are some frame/wheel or fork/wheel combinations that vibrate at a frequency which the Avid's excite.
    another dissatisfied Avid customer, well at least the BB7s are good the best fix for your problem is get a refund and buy Shimano or maybe Magura.life is too short to spend a lot of time fixing a bad product.

  8. #8
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    I had the Elixir R for three or four rides, and had that vibration. I had a Lyric, which I think might be stronger than a 29er. I had Magura Louise before the Elixir, and went back to them. I don't have that problem with the Louises.

    If the CPS hardware might be causing the problem, you could try another hardware even if you loose the CPS.

  9. #9
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    I've been riding my Elixir CRs for almost a year without that problem. I'd be inclined to suspect an alignment issue or a problem with fork flex.
    We sell quality bike headlights and flashlights.
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  10. #10
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    Facing brake mount tabs helps sometimes.

  11. #11
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    before you give up, you might try this- slightly loosen the caliper bolts, enough so that the caliper can "float" when you squeeze the brake lever.What this does is allow the caliper to be perfectly aligned with the rotor when squeezing the brake lever. Go for a test ride. If it works okay, it means you have an alignment problem, like the 2 previous posters have mentioned. It is a very common problem. This test is mainly for diagnosis of the problem, although I have left my caliper mounting bolts slightly loose on several rides, and really enjoy the feel of how smooth the braking is without a bit of rotor rub. I do put a small dab of blue locktite on the end of the bolts, and have never had a bolt come loose. Good luck.

  12. #12
    gran jefe
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    i'd sand the rotor, as suggested. anything to change the frequency at which your pads might be tempted to grab and release, causing vibration.

  13. #13
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    Thanks to all!!

    Nov0798's suggestion seems to be working! The sanding/grinding has made the vibration all but dissapear. Crazy!?! Resonance vibration as mentioned i guess... I also noticed the pad contact is a bit to low on the rotor so i am gonna add the small spacers as suggested. It has only been a couple small rides so I hope this lasts.

    For the record these are the first hydro's I have ever used. They came with a new bike(2010 Fantom29 Pro SL). Aside from this issue and the 3-4 month learning curve on how to adjust them properly and bleed them, which for me was required they are quiet and powerfull.. Now being the frugal person that I am elixir CR's are "cheap!" as in quality. I will not specifically buy Avid hydro's ever. I was/am so close buying new brakes: looking at Hope m4/x2 combo or XT's but these work and that saves $400-500.

  14. #14
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    I have the Elixir CRs too. What stopped my vibration was shimming the calipers up a mm or two. Just like nov0798 said....

    this:

  15. #15
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    way to go Dude!

    Thaks for putting up a great post for a problem solved with a bit of homemade engineering!

    I do believe this is an adjustment problem, and like other important components, these exacting parts should have an adjustment to allign the caliper to the disk, just like a newly installed printer ink cartridge.

    Sam in California



    How to adjust disk brakes with a steak knife

  16. #16
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    Wink Thanks!

    Hello!

    I have a mountain bike that I use for commuting.

    For months I had this problem. I tried organic pads with steel and aluminum and nothing. The steel ones were much quieter than the aluminum ones though, but I still got weird lever feeling and vibrations coming from it.

    The problem was so annoying that I stop braking hard, I changed all my driving style just not to hear the brake problems.

    I though about the calipers being too low but I never gave much importance to it, then I read this post and this morning I did an experiment AND THE PROBLEM GOT FIXED.

    I raised the caliper by moving the conic washers under it, I have around 1mm of pad now at the top of the rotor not making contact, but before the change I had about 2mm or more under the rotor that was not doing anything but hit the rotor spoked.

    Anyway, this COMPLETELY fixed ALL NOISES AND VIBRATIONS. I hope it stays like that.

    Thanks!

    Unfixable? Ongoing braking vibration is driving me crazy-brake.jpg

  17. #17
    Workin for the weekend!
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    I've done something similar with a spacer and had good results... I also put a drop of blue thread locker on each CPS washer to bond the stack together once it's all lined up properly. Makes a difference and keeps things tight...

  18. #18
    rebmem rbtm
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    I have around 1mm of pad now at the top of the rotor not making contact
    Your pads shouldn't overhang the rotor.

    How well do you think a brake will work when the overhanging unworn parts of the pad start to push against each other ?


  19. #19
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    You are right, however, the amount of material in both pads is not enough for them to touch each other. They probably will touch each other when both pads are totally worn out (or very close to).

    In any case, a set of pads lasts about 1.3 years with my daily use, I rather change them when they touch each other (once every year) than live with the vibrations and noises every day

    If someone wants to do it in a better way, just add washers until you elevate the pads high enough so they dont rub the rotors spokes.

  20. #20
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    Cool-blue Rhythm Photos about what I posted

    Here are the photos.

    You guys dont have an idea of the vibrations I got rid of. The braking power is more than before and super smooth. Before this I tried EVERYTHING, I spend a lot of time and money buying rotors and pads.

    So, honestly, I dont mind a lot about pads touching each other. It will eventually happen but it may take around 8 months for them to wear to that point. And since pads need to be monitored for wear anyway, the moment I see they are going to touch I will sand them or replace them.

    Unfixable? Ongoing braking vibration is driving me crazy-braketop.jpg

    Unfixable? Ongoing braking vibration is driving me crazy-brakedia.jpg

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