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  1. #1
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    Formula K24 Knocking sounds

    got a set of k24 160mm and i like em. not surprised that they'll make noise similar to the turkey gobble, but it's more like a faint knocking sound. I guess this is the same reason that tthe juicy's have the beloved turkeygobble?

    anyone experiencethe same? the rotors are 'shaped', not as extreme as the polygons, but similar...
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  2. #2
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    It looks like you're grabbing the arms of the rotor a bit. Slide a small washer between the caliper and the adapter.

  3. #3
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    Large knockers klacking free or loose ball sack. :14:

  4. #4
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    Misctoo,
    Before placing a washer between the caliper and adaptor, look through the vent on the back of the caliper and check to see if the high spots on the rotor are lining up with the top of the pad material. If they are lining up correctly as they should be, do not put a spacer between the caliper and rotor, as it will cause the pads to not fully contact the rotor. On the Oro the pad material will come down a bit further onto the arms than other brakes, this is normal and yours looks about normal to me...as far as I can tell by a picture from that angle.

    Here are a few things I would recommend checking for the knocking:
    -All fasteners torqued to spec? This is actually really important
    -Have you had your fork tabs faced?
    -Is your ft. hub or headset loose? How about those fork bushings?
    -Check to make sure the pad spring is set properly and allowing the pads to move freely.

    With regards to the "gobble"... Is it always happening or is in intermittent?

    If it is always happening, you could have some pad contamination, or facing the tabs and torquing the fasteners to spec could also help.

    If it is intermittent, check to notice if it is mostly after long DHs or heavy use when brake cools and then you start using it again. It is not uncommon to get a bit of noise out of them as the burn back off the glaze which develops.

    If none of that works, we should get you some of our sintered pads. They seem to sometimes fix noise problems which the organic pads have. I know that sounds backwards...but that is what we have found on the Oro.

    If you are want to chat about anything I just said, dont hesitate to contact us.

    Thanks

    Chris

    www.formulabrakeusa.com

  5. #5
    Meh.
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    Actually, listen to him. Now that I look at the rotor, it does seem to be grabbing the top edge just fine.

  6. #6
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    Quote Originally Posted by Formula Brake USA
    Misctoo,
    Before placing a washer between the caliper and adaptor, look through the vent on the back of the caliper and check to see if the high spots on the rotor are lining up with the top of the pad material. If they are lining up correctly as they should be, do not put a spacer between the caliper and rotor, as it will cause the pads to not fully contact the rotor. On the Oro the pad material will come down a bit further onto the arms than other brakes, this is normal and yours looks about normal to me...as far as I can tell by a picture from that angle.

    Here are a few things I would recommend checking for the knocking:
    -All fasteners torqued to spec? This is actually really important
    -Have you had your fork tabs faced?
    -Is your ft. hub or headset loose? How about those fork bushings?
    -Check to make sure the pad spring is set properly and allowing the pads to move freely.

    With regards to the "gobble"... Is it always happening or is in intermittent?

    If it is always happening, you could have some pad contamination, or facing the tabs and torquing the fasteners to spec could also help.

    If it is intermittent, check to notice if it is mostly after long DHs or heavy use when brake cools and then you start using it again. It is not uncommon to get a bit of noise out of them as the burn back off the glaze which develops.

    If none of that works, we should get you some of our sintered pads. They seem to sometimes fix noise problems which the organic pads have. I know that sounds backwards...but that is what we have found on the Oro.

    If you are want to chat about anything I just said, dont hesitate to contact us.

    Thanks

    Chris

    www.formulabrakeusa.com
    Thanks Chris XSL DFR

    yeah the knocking doesn't really show up until the rotors are hot and i'm squeezing hard to stop...and it's only the front...the rear is so powerful i just feather them and before they have a chance to knock i'm already off the rear brake.

    and no the tabs are NOT faced :blush2:
    i don't have a torque wrench, so i' don;'t think the bolts are torqued to spec..
    fork bushings and headset are tight and brand new.
    pad spring is strong and moves fine...

    i guess i have to do the first two items....thanks for the heads up! Customer service on mtbr....that rocks...

  7. #7
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    No problem!

    Seeing how the popping only happens under heavy braking, when a big load is placed on the ft. end...I am guessing it is more likely a problem with your headset, fork, or stem.

    What led you to the conclusion it was your brakes making the popping? I guess if it wasnít happening before you installed the Oros, it would clearly point to them.

    I spent 10+ years working and running service departments. Many of the creaking/popping noises in the front end can usually be tracked down to 3 different things:

    1. Fork (creaky/popping crown or loose bushings being common culprits).

    2. Headset (be sure to check the press fit of the crown race, bearing quality, and make sure that your top cap is compressing on the stem and not the top of the steerer tube, which would inhibit you properly adjusting the HS). If it is a loose ball HS, check the bearing cup/cone surfaces for pitting or damage.

    3. Stem (Grease those bolts and torque them to spec! I have experienced several stems which required consistent greasing of the bolts to remedy noise...especially in muddy conditions.

    Let me know what you find or if you need other pointers...

  8. #8
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    Quote Originally Posted by Formula Brake USA
    Funny...I got torqued to spec by one of those girls last week!

    Chris

    LMAO

    dogonfr your archive is looking up!

    i'm not thinking about brakes anymore....

  9. #9
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    OK!

    1. fork is a RS Pike, usu.running at 100-110mm, brand new , about 1 month old.
    2. headset is tight, bearings are smooth and fine, stem/top cap are installed correctly.
    3. stem looks fine, i' m a grease freak when it comes to bolts.

    i had monoM4's and there was incredible squealing but no 'knocking'. remember, the knocking only starts after the rotors are hot.

    i fractured my thumb and a messed up knee so i won't be able to replicate the knocking but as soon as i'm healed , it's back to the mtx track!


    also i was told that shortening the hydro lines can be done @ the master cylinder end, without new banjos or seals etc, as well as no bleeding necessary. is this true? i have a formula bleed kit i can use. but i've cut down monomini's+M4's without bleeding andthey werefine and i heard the same(if ddone carefully) could be done on the k24's....true, not true?

  10. #10
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    Misctwo,
    Check out our Website for some sweet detailed (w/pics) bleed instructions. To bleed them you will need a cuttable fitting kit, which comes with every aftermarket brakeset. If you are suave about it and donít let any fluid drip out of the line or the MC you can get away without bleeding...any small bubbles would just move right up to the reservoir. However, we do recommend filling one of the syringes with DOT 4 fluid, screwing the fitting into the MC port (lever off bike, port vertical) and back-pressuring the syringe to suck out any small bubbles in there.

    2 things to take note of: 1. be sure to pump the lever a few times after you shortened the hose and it is reattached. Just to make sure the bubble is in the reservoir and not the line when you backpressure the system. And 2. After backpressure, be sure to reapply pressure to the syringe plunger before removing it and capping it off. The reason being, that when you back-pressuring, the diaphragm in the reservoir sucks in on itself and you need to make sure to return it back to its correct resting position...

    Cap it off and you are set to goÖ

    Chris@formulabrakeusa.com

  11. #11
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    Quote Originally Posted by Formula Brake USA
    Misctwo,
    Check out our Website for some sweet detailed (w/pics) bleed instructions. To bleed them you will need a cuttable fitting kit, which comes with every aftermarket brakeset. If you are suave about it and donít let any fluid drip out of the line or the MC you can get away without bleeding...any small bubbles would just move right up to the reservoir. However, we do recommend filling one of the syringes with DOT 4 fluid, screwing the fitting into the MC port (lever off bike, port vertical) and back-pressuring the syringe to suck out any small bubbles in there.

    2 things to take note of: 1. be sure to pump the lever a few times after you shortened the hose and it is reattached. Just to make sure the bubble is in the reservoir and not the line when you backpressure the system. And 2. After backpressure, be sure to reapply pressure to the syringe plunger before removing it and capping it off. The reason being, that when you back-pressuring, the diaphragm in the reservoir sucks in on itself and you need to make sure to return it back to its correct resting position...

    Cap it off and you are set to goÖ

    Chris@formulabrakeusa.com

    awesome! your instructions are so much easier than the manual and yes i've got two sets of the new fitting kits..

    i used some mineral oil for the bleed......jus' kiddn!

    now all i have to figure out is where to put these formula decals...

  12. #12
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    Quote Originally Posted by misctwo
    awesome! your instructions are so much easier than the manual and yes i've got two sets of the new fitting kits..

    i used some mineral oil for the bleed......jus' kiddn!

    now all i have to figure out is where to put these formula decals...
    The decals will look really cool on the pedals.

  13. #13
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    Quote Originally Posted by dogonfr
    The decals will look really cool on the pedals.

    i'll try that but they won't last long

  14. #14
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    Hey Chris,

    I just realized one thing that may be the reason for the knocking...wheel wind up! the knocking i realized occurs when rotors are both hot and cold...it happens when i squeeze down on the lever very hard...that would make me think that the torque energy from the braking gets conserved into the wheel/spokes until it reaches a point where the energy has to release, making the wheel spin in a 'pulsing' manner. When the wheel pulses, the rotor will pulse, etc etc, and vice versa.

    i guess this knocking is similar to the rear wheel when skidding on a paved surface(decline tipped me off about this) the rear wheel would skip, just like an 18wheeler skidding and 'hopping' while the wheels are locked...

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