Disc brake judder

wruds
wruds Posts: 74
edited November 2016 in MTB workshop & tech
Hi, what causes disc brake judder when braking. My MTB has developed brake judder, only on the front disc, what could be the cause. Charge Cooker

Comments

  • The Rookie
    The Rookie Posts: 27,812
    Usually some contamination or a warped disc.

    Certain aspects like fork stiffness can make it worse.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • JBA
    JBA Posts: 2,852
    Also check the caliper bolts are tight and that the headset hasn't worked loose.
    “Life has been unfaithful
    And it all promised so so much”

    Giant Trance 2 27.5 2016 ¦ Sonder Broken Road 2021¦ Giant Revolt Advanced 2 2019 ¦ Giant Toughtroad SLR 1 2019 ¦ Giant Anthem 3 2015 ¦ Specialized Myka Comp FSR 2009
  • fat daddy
    fat daddy Posts: 2,605
    Check your pads as well, last time I had judder it turned out to be a pad that had started to dusintergrate snd had a couple of chunks missing on the leading edge
  • rockmonkeysc
    rockmonkeysc Posts: 14,774
    Check the headset, fork bushes and brake mounts (caliper and disc) for play.
    Transition Patrol - viewtopic.php?f=10017&t=13070235
  • wruds
    wruds Posts: 74
    Many thanks for all of the suggestions. Will go through each in turn and see where I end up.
  • swod1
    swod1 Posts: 1,639
    What size disc you using on front?

    On my bike I had it and upping disc to a 180 stopped that from happening.

    Could be one of the causes already mentioned though so check them first.
  • rockmonkeysc
    rockmonkeysc Posts: 14,774
    Changing the size of the rotor won't stop brake judder.
    Transition Patrol - viewtopic.php?f=10017&t=13070235
  • wruds
    wruds Posts: 74
    It's actually a new bike. So I'd be surprised if discs were an issue. May just be crud, I've had the wheel off a few times as of late. Thanks for all feedback.
  • JGTR
    JGTR Posts: 1,404
    RockmonkeySC wrote:
    Changing the size of the rotor won't stop brake judder.

    Might do, could be a resonance thing.....more than likely the new disc cured it rather than the increase in size
  • compuwiz_uk
    compuwiz_uk Posts: 139
    wruds wrote:
    It's actually a new bike. So I'd be surprised if discs were an issue. May just be crud, I've had the wheel off a few times as of late. Thanks for all feedback.


    dont assume disks are not the issue, even with a new bike.

    i have had to seriously adjust the brake disks on one new bike with a mere 1.6 miles on it & tinker with 2 more with slight trueing adjustments to cure brake rub with the same mileages on em - all again bought new.

    at most move that option to a lower section of the list but dont remove it off the list fully :)
  • 02gf74
    02gf74 Posts: 1,168
    I have found that lightweight disc rotors, those that have big gaps in the braking surface, will judder. Example below.

    LifeLine-Floating-Disc-Rotor-160mm-Disc-Brake-Rotors-LL-DR08FA160.jpg?w=1000&h=1000&a=7
  • The Rookie
    The Rookie Posts: 27,812
    All my bikes runs lightweight discs and none judder....so 'will judder' is wrong.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • 02gf74
    02gf74 Posts: 1,168
    you missed the part with the wide gaps.

    both hope saw and formula discs are reasonably lightweight and neither judders as they have lots of small holes instead of big ones.
  • The Rookie
    The Rookie Posts: 27,812
    My lightweight alligator have big gaps.

    The worst disc I've come across for judder was a saw tooth with no gaps at all.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • rockmonkeysc
    rockmonkeysc Posts: 14,774
    JGTR wrote:
    RockmonkeySC wrote:
    Changing the size of the rotor won't stop brake judder.

    Might do, could be a resonance thing.....more than likely the new disc cured it rather than the increase in size

    Resonance won't do that. Although the resonance of a disc rotor on its own would be a pretty low frequency, under braking loads it's going to be considerably higher (a good thing)
    A smaller rotor would have a higher resonant frequency so if that was the cause of the judder it would be much worse with a bigger rotor.
    Transition Patrol - viewtopic.php?f=10017&t=13070235

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