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  1. #1
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    Caution;  Merge;  Workers Ahead! Help pls! Major front brake shudder in used 2013 Stumpjumper FSR. What would you do?

    Hi-

    I just purchased a used, 2013 Stumpjumper Comp FSR from a rental shop that is several hours away. When braking hard with the front brake, the vibrations are so bad the front fork/shock shudders. The shuddering is a massive back and forth flexing of the front shock. It is definitely being induced by vibrations in the brakes.

    I've read multiple forums and it seems it is likely caused by the stock Avids. The shop owner had installed new pads when I picked up the bike. We noticed a slight shudder, but after playing around with the pads and me doing several miles of downhill, it went away.

    I bought the bike and washed it at home. However, after washing the bike off, the shudder was back in full force.

    Is there anything I can tune/tweak to get rid of the shudder?

    I've read a lot of complaints on the Avids, even on new bikes. Are they really that bad? Should I try to replace them (was reading about Shimano IceTech)?

    Should I punt and try to return the bike? Returning the bike only makes financial sense if I can get a deal at my LBS, and the new bike would not have this issue.

    Thanks!

    PS Is this the best forum category to post this in?

  2. #2
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    Hi-

    For reference (and searching) I have the stock, Custom Avid Elixir 5 SL, hydraulic disc, HS-1 rotor. M: 180mm. I am not sure what type of replacement pads he used.

    The rears brakes seem fine, so far.

  3. #3
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    Help pls! Major front brake shudder in used 2013 Stumpjumper FSR. What would...

    Were the pads bedded in?

  4. #4
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    Quote Originally Posted by foxpuppet View Post
    Were the pads bedded in?
    Short answer: not formally.

    I asked the shop that. He said the pads are basically bedded when people ride downhill (this was up at Vail, so lift-ride up). That happened to be me, however, I did not do the jogging/walking thing I've read about because of the shop owner's advice. During the several miles of downhill I did play around with various amounts of pressure on the front brake. I didn't feel any shudder during my ride (very bumpy) or at the end of the day.

    The next day, after I rinsed the bike off the shudder was back BIG TIME. I only rode it up and down my street a few times to dry the bike off.

    Thanks for posting.

  5. #5
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    Avids are problems for many riders.
    Bolt this SLX on for $70 and you will not have problems.
    Clean the rotor with Brake Cleaner and I wipe my bike instead of hose it.
    BlueSkyCycling.com - Shimano SLX M666 IceTech Disc Brake w/Adapter

  6. #6
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    Quote Originally Posted by eb1888 View Post
    Avids are problems for many riders.
    Bolt this SLX on for $70 and you will not have problems.
    Clean the rotor with Brake Cleaner and I wipe my bike instead of hose it.
    BlueSkyCycling.com - Shimano SLX M666 IceTech Disc Brake w/Adapter
    Keep in mind the rear brake cable needs to be 1700 mm version. The stock 1200 from blue sky is not long enough. This is a special cable and not the typical brake cable that cost 19.99. Is more like 47 to 54 bucks . Add labor to it and these slx brakes from blue sky are not cheap.

    Get the xt from them that has the 1700mm cable stock.
    Last edited by Loll; 09-03-2013 at 08:24 AM.

  7. #7
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    Shuddering is caused by different braking force over the surface of the rotor. Could be unevenly bedded in, contaminated, warped or worn out of whack. It's not an Avid specific problem; I'm riding a '13 Epic with a front Magura brake with similar problems.

    Get the bike shop to put on a new rotor and pads and make sure the pistons are moving evenly. Follow the Avid bedding in procedure. Let them keep the old parts.

    FWIW, the Avids on my '11 have worked perfectly through several pad changes, although they were haywire when I got the bike used. And the Maguras have the dreaded turkey gobble when warm, so it isn't an Avid patent noise after all. You only hear from the people having problems and there are zillions of Avids out there. That said, Shimanos are a quieter and less problematic brake system overall.

  8. #8
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    Avids are notorious for these sorts of problems. I fought with the Elixir 4's on my 2010 FSR XC for almost two years before giving up and getting some SLX brakes. I kept the original rotors. No problems since the switch. Here is a 37 page thread on Avid vibrations and noise.

    The Juicy brake turkey warble/vibration MEGA THREAD

    Even though it is titled "juicy brake turkey warble...." there are probably 2 or 3 hundred posts from people with Elixirs. There are several "solutions" in this thread. I tried a few, nothing really took care of the problems I was having.

  9. #9
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    Quote Originally Posted by philipb View Post
    Avids are notorious for these sorts of problems. I fought with the Elixir 4's on my 2010 FSR XC for almost two years before giving up and getting some SLX brakes. I kept the original rotors. No problems since the switch. Here is a 37 page thread on Avid vibrations and noise.

    The Juicy brake turkey warble/vibration MEGA THREAD

    Even though it is titled "juicy brake turkey warble...." there are probably 2 or 3 hundred posts from people with Elixirs. There are several "solutions" in this thread. I tried a few, nothing really took care of the problems I was having.
    Thanks. I read through that thread but didn't see much on shudder. The net of that thread was that Avid's seem to be higher maintenance and problematic, however, most threads of that nature focus on issues. I didn't read a clear fix.

  10. #10
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    Quote Originally Posted by Loll View Post
    I

    Keep in mind the rear brake cable needs to be 1700 mm version. The stock 1200 from blue sky is not long enough. This is a special cable and not the typical brake cable that cost 19.99. Is more like 47 to 54 bucks . Add labor to it and these slx brakes from blue sky are not cheap.

    Get the xt from them that has the 1700mm cable stock.
    Are you saying that buying locally includes install, or that you need to add more parts-cost than what is being shown?

    Thanks,

  11. #11
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    Thanks for all of the responses.
    I'll call the bike shop and see what they can offer. The shop is 2 hours away, so it's not easy to get there.

    They did put on new pads and tweak around with them while I was there. They also centered and re-centered the calipers. How much of this might be related to bleeding?

    The shop also carries Shimano. He offered parts at his cost. Maybe I can swing the swap-out.

    I paid $1800 out the door ($1650 plus tax). If I have to rebuild a lot, I'm getting close in price to a new, stock bike. How much would you deal with versus just trying to return the bike? I've read that a lot of people buy a new bike and immediately upgrade parts. I can see why, but my goal is to stay within a price. I'd hate to get a new bike and have a similar issue.

    Any general thoughts on the dollars and what you end up with?

  12. #12
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    The Avids are hit and miss for sure, had different trouble with both my juicy 3 and 5 brakes. I still have trouble with the 3's but the 5's quit giving trouble after short period. Been riding them now for 4 yrs off and on. Quiet great braking power. Still having trouble with shudder with 3's on a 09 fsr XC Speci. Best brakes I've had so far are X2 hopes. But I've ridden Shimano XT and SLX both seem good, quiet and smooth
    Disclaimer: Always get a second opinion cause I'm just guessing

  13. #13
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    The xt come stock with 1700 mm cable if u buy from bluesky. It is more expensive up front. The Slx , u need to buy the expensive longer cable and have it install if u dont know how to do it well yourself. With labor, the xt is cheaper.

    Buying locally, u can ask the shop to get the 1700 version, but it is likely much more expensive than bluesky.

    The elixir on my bike suck. I did change brake pad and rotor per the stam brake thread. It works bit other problems arised. Decide to toss them. Funny i had juicy on my nomad and it works great. Not one problem after switching to organic pad. I am thinking sram and specialized dont go well together

  14. #14
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    Quote Originally Posted by bulerias View Post
    Shuddering is caused by different braking force over the surface of the rotor. Could be unevenly bedded in, contaminated, warped or worn out of whack. It's not an Avid specific problem; I'm riding a '13 Epic with a front Magura brake with similar problems.

    Get the bike shop to put on a new rotor and pads and make sure the pistons are moving evenly. Follow the Avid bedding in procedure. Let them keep the old parts.

    FWIW, the Avids on my '11 have worked perfectly through several pad changes, although they were haywire when I got the bike used. And the Maguras have the dreaded turkey gobble when warm, so it isn't an Avid patent noise after all. You only hear from the people having problems and there are zillions of Avids out there. That said, Shimanos are a quieter and less problematic brake system overall.
    Err, no, it's caused by the caliper resonant frequency. This happens with cars and all sorts of other vehicles, although if designed properly, it usually doesn't happen. It's an oversight and unpredicted result usually of joining two components/systems and not understanding the interaction between the two. Tacoma Narrows bridge. That's your Avid shudder.

    One way this is sometimes solved is by adding stick-on weights to the caliper. Otherwise it can be a total wild goose chase trying to come up with a solution, other than switching brakes.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  15. #15
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    Hmmm.... They guy I bought the bike from mentioned he "upgraded" the brakes. I know he at least upgraded the levers because I saw the broken one he was fixing up.

    So... at least the levers and possible the rest of the set-up are Avid Elixir Trail 9s. Are these supposed to be an upgrade from the stock parts on the bike? Can you tell from the attached pics if he also upgraded the calipers?

    The hydraulic cabling/tubing is attached with several zip ties. Did he use the wrong length cable when he put these on (I can take a pic if needed)? Would that cause any issues? Do you see any issues with the way the calipers are mounted?

    Thanks!


    Help pls!  Major front brake shudder in used 2013 Stumpjumper FSR. What would you do?-img_1707.jpgHelp pls!  Major front brake shudder in used 2013 Stumpjumper FSR. What would you do?-img_1704.jpgHelp pls!  Major front brake shudder in used 2013 Stumpjumper FSR. What would you do?-img_1702.jpg

  16. #16
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    Looks (by the wear marks) to be mounted too close to the hub.

  17. #17
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    Avid brakes suck. You have a nice bike, just throw on a new brakeset if money allows.
    Get some 80 grit (or whatever you have) sandpaper and sand the pads down until they look "new". Wipe the rotors off with alcohol. Worked for my Maguras.
    Livin' the dream.

  18. #18
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    Quote Originally Posted by broncbuster View Post
    Looks (by the wear marks) to be mounted too close to the hub.
    I am wondering if those are scuff marks caused by shudder.

    Do the mounting brackets (?) with the 17.5mm marking look correct/appropriate? I wonder if they are not stiff enough.

    Any thoughts on that?

  19. #19
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    Can you tell if the pads are riding in the appropriate area of the disc? If so something else has to be making those marks and probably the cause of the shudder. The hardware looks normal and should be stiff enough. If the pads are the cause of the marks then maybe a 170mm disc or different hardware is the answer?

    I had a bike (with Hayes Nine brakes) that was always giving me a lot of problems I finally converted it to mechanical disc brakes. Not a bad way to go, the ones I got are very easy to adjust and very strong.

  20. #20
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    Alligator Windcutter Colored Disc Rotor | Alligator | Brand | www.PricePoint.com
    These will solve your problem Ive put them on a dozen bikes with the issues you are having and it cured it on everyone of them... avid rotors suck...
    I always type in bold cuz I'm blind as a bat
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  21. #21
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    You can try going back to the 160MM rear rotor instead of the 180mm with that hookie spacer set up.
    Personally I hated the Avid breaks on my SJ, I'd just say get the SLX or XT brakes and be done with the problem.
    13 Lenz Lunchbox punkass

  22. #22
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    Quote Originally Posted by Jayem View Post
    Err, no, it's caused by the caliper resonant frequency. This happens with cars and all sorts of other vehicles, although if designed properly, it usually doesn't happen. It's an oversight and unpredicted result usually of joining two components/systems and not understanding the interaction between the two. Tacoma Narrows bridge. That's your Avid shudder.

    One way this is sometimes solved is by adding stick-on weights to the caliper. Otherwise it can be a total wild goose chase trying to come up with a solution, other than switching brakes.
    I think the shudder the OP was referring to was a pulsing that tends to make the fork move fore and aft a bit. In a sense, the fork is resonating to a pulse in the brake system.

    The calliper resonant frequency is in a completely different frequency range altogether. If the shudder is at wheel rotation speed then you've got what I'm talking about, i.e. once per revolution or twice. Callipers will squeal or honk. Rear brakes attached to stays can resonate with the stay but front brakes attach to fork legs and they are oil damped and considerably larger.

    If the rotor is kooky or unevenly bedded it isn't a resonance in that sense and no amount of voodoo will fix it.

  23. #23
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    Quote Originally Posted by TwoTone View Post
    You can try going back to the 160MM rear rotor instead of the 180mm with that hookie spacer set up.
    Personally I hated the Avid breaks on my SJ, I'd just say get the SLX or XT brakes and be done with the problem.
    Hi. For clarity, the pics are of the front brakes/rotors.

    The rear brakes are thankfully pretty good.

  24. #24
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    Quote Originally Posted by broncbuster View Post
    Can you tell if the pads are riding in the appropriate area of the disc? If so something else has to be making those marks and probably the cause of the shudder. The hardware looks normal and should be stiff enough. If the pads are the cause of the marks then maybe a 170mm disc or different hardware is the answer?
    I played around a little this weekend and noticed when I squeeze the front brakes, the rotor bends a little. The rotor is not warped, and the "bending" is there, regardless of the wheel position. I'm assuming this means the caliper has somehow rotated.

    When I picked up the bike, the tech showed me his "trick" of loosening both screws on the front caliper, squeezing the brakes to center it, and then tightening in place. Assuming his trick had properly aligned the brakes, how did they move so much, and why would they essentially rotate? Is it common for brakes to rotate like that?

    Anything I should know before I try the same trick? Do I just hand-tighten the calipers in place?

  25. #25
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    I've run into this problem with headsets without enough preload and forks with trashed sliding bushings. So check that before you spend money.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

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