formula k24 with zzzzzzzzzzzzzzzz sound- Mtbr.com
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  1. #1
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    formula k24 with zzzzzzzzzzzzzzzz sound

    Hi,

    I just install formula k24 and use it twice in dry condition. (160 front and rear).

    Rear is dead silent, however the front makes a zzzzzzzzzzzz sound (in the lever I think not the caliper) like an air buble inside. Front brake performance is excelent thou...., no vibration or whatsoever in the lever, just nice

    Is the zzzzzzzzz sound normal? How to solve this (since my rear is silent).

    Thanks,

  2. #2
    Nightriding rules SuperModerator
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    it could be some minor rubbing.... I sometimes get some slight rubbing when the front gets up to speed (especially with "bigger" rotors --- 180,203mm)

  3. #3
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    zzzzzzzz only during brake

    The zzzzzzzzz sound is only when I hit the brake and speed is above 20km/hr. If I brake at walking speed its silent.

    I dont think its rubbing, since when I ride and not toucing the brake lever, its silent.

    Thanks,

  4. #4
    Now with 20% more fat!!
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    I have a set of K24s on my Sheep and they are silent (so far)... I don't think that the sound is normal. Perhaps the great guys at Formula have suggestions. I'd definitely give them a ring and see what they say. Make sure to post back with your results, and good luck!

  5. #5
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    lhmtb,

    The noise you hear is not abnormal. It can generally be attributed to one of two different things:

    1. Air which expands due to heat and then exits the holes in the rotor slightly pressurized.

    2. Depending on the tolerances’ of the mounts on your fork or frame. It is possible that the caliper is sitting a bit low in relation to the braking track on the rotor. If this is the case, the arms may be having more contact with the pads then is appropriate and causing the noise. Check the top of your caliper and note where the top of the pads sit in relation to the high points on the rotor. If the rotor extends above the pad more than 1mm this might be attributing to the noise as well. If it is well below, try putting .5mm washers in between the caliper and adapter.

    In some cases, changing the pads to the sintered version will make this noise go away but it is not guaranteed.

    As you probably noticed, it is not affecting the performance of your brakes.

    We made some slight changes to our rotors which can also sometimes affect the noise. The part numbers on newer design rotors end in 9x-00 whereas the older ones ended in 8x-00. The x would be a number which changes depending on the rotor size.


    Cheers,

    Chris Costello
    Formula Brake USA

  6. #6
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    I think Chris nailed it with #1, I have the exact same noise on my XTR's and it puzzled me for ages, silent slow but a sure thing when I'm at speed, on mine it is the air in the little holes making the sound, I think you'll find a lot of rotors with small holes do this. My Hayes on the other hand has large slots so there is no air noise.
    You probably only hear the front (not the rear as well) because when you are moving the sound passes you where the rear is gone before you can hear it. If you could get closer to the rear when braking at speed (not sure how this would be done! might need a riding buddy to do it) you will probably find the rear does it aswell.

  7. #7
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    Thanks Chris, I'll check it

    Quote Originally Posted by Formula Brake USA
    lhmtb,

    1. Air which expands due to heat and then exits the holes in the rotor slightly pressurized.

    2. Depending on the tolerances’ of the mounts on your fork or frame. It is possible that the caliper is sitting a bit low in relation to the braking track on the rotor. If this is the case, the arms may be having more contact with the pads then is appropriate and causing the noise. Check the top of your caliper and note where the top of the pads sit in relation to the high points on the rotor. If the rotor extends above the pad more than 1mm this might be attributing to the noise as well. If it is well below, try putting .5mm washers in between the caliper and adapter.

    Cheers,

    Chris Costello
    Formula Brake USA
    Thanks for the prompt reply

    For reason #1, I dont think its the issue since the noise already there when the brake is still cold (when I start ride the noise start whenever I press the brake).

    I'll check for caliper rotor height (#2) this weekend. Hopefully those washers can eliminate the noise.

    Cheers,

  8. #8
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    Quote Originally Posted by lhmtb
    Thanks for the prompt reply

    For reason #1, I dont think its the issue since the noise already there when the brake is still cold (when I start ride the noise start whenever I press the brake).

    I'll check for caliper rotor height (#2) this weekend. Hopefully those washers can eliminate the noise.

    Cheers,
    Just so you know, mine do it at any temp. I think it's just the air pressure.

  9. #9
    lurkio
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    In my experience, the zz noise is usually a slightly mis-aligned caliper and not really a problem, you can fiddle about for aeons to stop it but if it doesn't bother you then don't worry
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  10. #10
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    Quote Originally Posted by si,s
    In my experience, the zz noise is usually a slightly mis-aligned caliper and not really a problem, you can fiddle about for aeons to stop it but if it doesn't bother you then don't worry
    I change my j7 to k24 because j7 is very noisy and its cause vibration sometimes when I brake hard.

    With k24, no vibration, rear silent but front has some zzzzzzzz noise, not loud but still you can hear it.

  11. #11
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    Quote Originally Posted by si,s
    In my experience, the zz noise is usually a slightly mis-aligned caliper and not really a problem, you can fiddle about for aeons to stop it but if it doesn't bother you then don't worry
    I change my j7 to k24 because j7 is very noisy and its cause vibration sometimes when I brake hard.

    With k24, no vibration, rear silent but front has some zzzzzzzz noise, not loud but still you can hear it.

  12. #12
    Bodhisattva
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    Quote Originally Posted by lhmtb
    I change my j7 to k24 because j7 is very noisy and its cause vibration sometimes when I brake hard.

    With k24, no vibration, rear silent but front has some zzzzzzzz noise, not loud but still you can hear it.
    Both my front Bianco & K24 do the same. Doesn't matter if its a 180 or 203mm rotor. Happens when first engaging the brake and disappears under firmer pressure. Rear is dead silent. Doesn't bother me and Formula Chris' explanation sounds reasonable.

  13. #13
    Phil from San Diego
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    I just changed the fork and had to use a different adapter up front.. it was definately rubbing something in the caliper initially. now it's starting to go away...

    I think I'll take a better look when I get home and start hunting for a couple of .5mm spacers. Come to think of it, I might as well throw on the sintered pads while I'm at it.

    Thanks Chris.

    Phil.

  14. #14
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    Hey mine does the same, it really isn't an annoying sound and like others only happens in the front, only when fast and only very quiet, sounds kinda cool. Amazing brakes though!

  15. #15
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    Quote Originally Posted by sp3000
    You probably only hear the front (not the rear as well) because when you are moving the sound passes you where the rear is gone before you can hear it.
    For that to happen, you'd have to be going faster than the speed of sound. That would be one hell of a bike!

  16. #16
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    I have been thinking long and hard about replacing the J5's on my Moto-lite and the El camino's on my Indy Fab 29er SS with either Formula's, Avid Codes (although I have heard that they still have the same problems as the Juicy's do), or the Magura Louise or Marta's. Aside from the noise (can't be as bad as the J5's) how are they performing for you? I weigh 285lbs and need really good brakes. Are they going to work for someone my size or should I get downhill type brakes (Codes) for the power? I really need good modualtion as well as pure pucker power. Do the Formula's deliver?

  17. #17
    thecentralscrutinizer
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    Quote Originally Posted by EDDIE JONES
    I have been thinking long and hard about replacing the J5's on my Moto-lite and the El camino's on my Indy Fab 29er SS with either Formula's, Avid Codes (although I have heard that they still have the same problems as the Juicy's do), or the Magura Louise or Marta's. Aside from the noise (can't be as bad as the J5's) how are they performing for you? I weigh 285lbs and need really good brakes. Are they going to work for someone my size or should I get downhill type brakes (Codes) for the power? I really need good modualtion as well as pure pucker power. Do the Formula's deliver?
    I hear they do. Even for the big guys.
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  18. #18
    thecentralscrutinizer
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    Quote Originally Posted by EDDIE JONES
    I have been thinking long and hard about replacing the J5's on my Moto-lite and the El camino's on my Indy Fab 29er SS with either Formula's, Avid Codes (although I have heard that they still have the same problems as the Juicy's do), or the Magura Louise or Marta's. Aside from the noise (can't be as bad as the J5's) how are they performing for you? I weigh 285lbs and need really good brakes. Are they going to work for someone my size or should I get downhill type brakes (Codes) for the power? I really need good modualtion as well as pure pucker power. Do the Formula's deliver?
    Double post. URgh!
    2015 Kona JTS
    2014 Scott Scale 710
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  19. #19
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    rotor & pads position checked

    Quote Originally Posted by Formula Brake USA
    lhmtb,

    The noise you hear is not abnormal. It can generally be attributed to one of two different things:

    2. Depending on the tolerances’ of the mounts on your fork or frame. It is possible that the caliper is sitting a bit low in relation to the braking track on the rotor. If this is the case, the arms may be having more contact with the pads then is appropriate and causing the noise. Check the top of your caliper and note where the top of the pads sit in relation to the high points on the rotor. If the rotor extends above the pad more than 1mm this might be attributing to the noise as well. If it is well below, try putting .5mm washers in between the caliper and adapter.

    We made some slight changes to our rotors which can also sometimes affect the noise. The part numbers on newer design rotors end in 9x-00 whereas the older ones ended in 8x-00. The x would be a number which changes depending on the rotor size.


    Cheers,

    Chris Costello
    Formula Brake USA
    Hi Chris,

    I've checked the rotor and pads position, looking at the rotor seems that the high point of braking tracks also have a pad scratch so I think its relatively high position. No braking mark in the rotor arm.

    My rotor code is the newer design 9x-00.

    The noise is still there on front brake but its not loud, I havent have tried it in the wet condition.

    Braking power and modulation is goooood....

    Thanks and regards,

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