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  1. #1
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    Juicy 7 gobble still here - need suggestions

    Here's what I've done to date:
    Started with '05 Juicy 7's and polygon rotor and OEM pads - squealed and turkey gobbled like heck. Confirmed pads were contacting legs of rotor - raised caliper with washers - still gobbled - removed washers and grinded pad material away to eliminate rotor leg contact - still gobbled. Replaced OEM pads with new Avid resin pads and reinstalled washers to eliminate rotor leg contact - still gobbled. Changed to Hayes V6 rotors with Avid resin pads, removed washers, confirmed pads were not contacting rotor legs - still gobbled.

    Along the way, I've tried sanding the pads which quites things for maybe 1 ride. I'm following the pad alignment procedure listed on this forum and am getting the calipers about as aligned as possible. The rotors are true. Yesterday I swapped wheels with a buddy who has XTR rotors and my setup still gobbled but not as loud. My V6 rotor on his bike with Formula brakes didn't gobble or squeal. Through process of elimination, it sounds like the problem is with the J7 caliper. It seems like the gobble shows up after the pads are bedded in and begin to grab well, so my theory is that heavy braking causes something within the caliper to vibrate causing the gobble - possibly the pad-to-piston interface?? So my next idea is to try some of the automotive pad quieting goo that is applied to the backs of the brake pads - however, I just think it will get scraped off as the pads are installed in the J7 caliper.

    Beyond that, does anybody have any other suggestions or ideas to quiet these brakes?

    Thanks,

    Dan

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    Setup issue. I've got an o4, o5, o6, and o7 caliper, all mismatched. No stuttering issues with any of them.

    Have you tried letting it bed all the way before sanding or cleaning? There is such a thing as sanding too much.

  3. #3
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    "Setup issue" - please elaborate. Does that mean the alignment is wrong, incorrect bedding procedure, wrong mix of components, etc.?

    I only sanded the pads once. It was when I elevated the caliper to get the pads off the polygon rotor legs.

  4. #4
    Never enough time to ride
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    Had the same issue with my 04 Juicy's. The only solution I tried that actually worked was getting the new G2 rotors from Avid. They seem to be a bit different alloy than the previous generation and the braking surface seems to be a bit larger.

    Givem a shot, they're still a great brake.

    happy trails...

    squish
    Get out and ride!

  5. #5
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    No doubt, the J7 is a great brake - and the levers are really nice as well. But watch e-bay kids cause these damn things gotta GO! To make sure there wasn't something in my bike causing the gobbling, my buddy loaned me some El Camino brakes (sorry Hayes, compared to the J7's I'm not impressed!!) and they function QUIETLY on my bike! So I eliminated the bike, wheels, and rotor as the problem. Yeah, everything works differently together, but this is the best idea I could come up with to eliminate the wheels, fork, pivots, etc. as the source of the gobble.

    I tried the clean sweep rotor - sounded exactly the same as the Hayes V6 rotor (gobbled like hell). I then tried sanding the pads - still gobbled like hell. Note - the brakes were bedded per Avid's bedding procedure after each component change to get a valid indication of the results of the change. Each time, I noticed the gobble worsened as the brakes began to bed and grab better. I'm done spending money swapping parts to try to quiet these J7's! Got some Formula's on order.

    It's a shame - the J7's are impressive brakes and the levers are very well designed and constructed - I really WANTED to make these things work but I'm tired "chasing the turkey".

  6. #6
    11 is one louder than 10
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    new organic pads. New round rotors, or 07 rotors, or the j5 roundagon rotors (heavier).

    Align pads while rotating wheel backwards Slowly. Alternate tightening the top and bottom bolts. Check for alignment. Break in slowly.
    "The thing is, Bob, it's not that I'm lazy, it's that I just don't care."

  7. #7
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    Did it! All of what you suggested! And in various combinations - organic with polygon, organic with G2, orgaic with Hayes V6, sanding, not sanding, align while rotating forward by hand with the crank, backward by hand, tighten top bolt first then lower, tighten lower then top, rotate - tighten just a little, rotate, then tighten some more, etc. That's what kills me - I've tried everything anyone has suggested and still have the gobble.

    Thanks for the input, though!

  8. #8
    meh....
    Reputation: Monte's Avatar
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    Got Dremel?

    Quote Originally Posted by wddamf
    Did it! All of what you suggested! And in various combinations - organic with polygon, organic with G2, orgaic with Hayes V6, sanding, not sanding, align while rotating forward by hand with the crank, backward by hand, tighten top bolt first then lower, tighten lower then top, rotate - tighten just a little, rotate, then tighten some more, etc. That's what kills me - I've tried everything anyone has suggested and still have the gobble.

    Thanks for the input, though!
    Here's what I did to kill my gobble. Dremel makes a small abrasive wheel, it looks like a small scotchbrite pad. Dremel about 1/2 throttle, go over the braking surface and clean it up. You aren't looking to remove a lot of material, just to break up the surface glaze.

    Monte

  9. #9
    Nightriding rules SuperModerator
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    Also remember tho check the CPS washers... if you ever overtightened them, they might now have a "deformed position" to which they go back as you tighten them... causing your caliper to misalign every time....

  10. #10
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    Try swapping to Hopes.

  11. #11
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    Also remember tho check the CPS washers
    Yeah, I thought about that. I checked them for deformation and they're OK. I'm confident the alignment was/is OK. Visually, the're in line with the rotor in both the radial and axial planes, and the pads contact the rotor equally and at the same time when the lever is slowly squeezed.

    Try swapping to Hopes
    Naw... I'm swapping to Formula K24's. I luckily have buddys riding El Camino's, Mono's, and K24's so I got to test ride each - I like the Formula's. Oh yeah - ALL of their brakes are quiet! One of my other buddys had J7's and they gobbled on his Turner just like on my Titus. He ditched his J7's too! I hate to dog a product that is so well built and performs so well but I've put forth plenty effort to resolve the issue with no success. Thanks to everybody for all the suggestions.

    Dan

  12. #12
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    I don't find the Juicy 7's to be well built at all, especially at the price of others. Their problem was fixing problems that didn't truly exist, the speed dial system that wasn't truly needed, and the rotors. After two years on the other bike of fumbling with them and having leaking reservoir seals and a master cylinder on one starting to act up, it's time to get rid of them. Used hopes and will never look back. Quiet, set and forget, never drag, settings don't change based on temps, modulation is fantastic, and never have to think about them. The build quality is phenomenal as well.

  13. #13
    Meh.
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    [QUOTE=Jerk_Chicken]settings don't change based on temps, QUOTE]

    Yeah... Because Hope definitely did some voodoo magic on their brakes so it ignores the boiling point of DOT fluid, brake fade, heat dissipation, and other laws of physics.

    The IS caliper is such a pleasure to work with. Face the tabs, space it out, compatibility issues, etc. More work than is neccesary. Sorry to say this, but if a wrench can't set up a post mount caliper, he doesn't deserve to be building bikes.

    I've run Avid brakes for some time now. I've had a bad piston which allowed dirt into the system, it eventually mucked up the MC. But SRAM took care of me. No company will be able to produce a brake that is 100% problem free 100% of the time. Yes, they did produce some faulty rotors. But I still believe that many of the stuttering issues had/have more to do with setup and break in than anything else.

  14. #14
    Master of None
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    Which side gobbles? Front? Rear? Both?

    Are your spokes good and tight?

    I have '05 Juicy 5 (same caliper) with polygon rotors, OEM pads, and no gobble. Sometimes it makes a cool boing-boing sound at low speed but it's not loud at all.

    They have amazing power and modulation. My singlespeed now has better brakes than my big trail bike...

  15. #15
    I <3 29ers
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    Quote Originally Posted by wddamf
    Naw... I'm swapping to Formula K24's. I luckily have buddys riding El Camino's, Mono's, and K24's so I got to test ride each - I like the Formula's. Oh yeah - ALL of their brakes are quiet! One of my other buddys had J7's and they gobbled on his Turner just like on my Titus. He ditched his J7's too! I hate to dog a product that is so well built and performs so well but I've put forth plenty effort to resolve the issue with no success. Thanks to everybody for all the suggestions.

    Dan
    That's what I did! Instant fix. First time, right out of the box, no ****ing around with bs this/that/the other. Mount and GO!

    For reference - I was experiencing problems with BB7s, not a Juicy model. I think it's an Avid problem, not a Juicy one. (shrug) JMHO and IMAE, YMMV and all that other stuff.

    Let us know how it goes, wd.
    I ..... need ..... DIRT!!!!!

    ... and cookies.

  16. #16
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    Front and rear gobble equally loud.

    Spokes are tight, too.

  17. #17
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    I have BB7s, which work, and Formula Oros, which work. I definitely prefer the Formulas but the BBs are nice. Half - no, 90% - of the battle is making sure the rotor is true.
    All problems in mountain biking can be solved by going faster, except the ones that are caused by going too fast.

  18. #18
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    Yeah... Because Hope definitely did some voodoo magic on their brakes so it ignores the boiling point of DOT fluid, brake fade, heat dissipation, and other laws of physics.
    Heh!! That's funny! I had a little problem with pump-up in the heat of the summer but that was because I had overfilled them during bleeding - releasing a few drops of fluid solved that problem.

    Will, you keep referring to "setup issues" - give me some suggestions of what to tweak - the pads visually look square to the rotor, the rotor is true, the rotor bolts are to their torque spec, the caliper bolts and adapter bolts are tight, the bike's pivots are tight, etc. I don't mind fiddling with this (until my new Formula's arrive!! ) but I honestly don't know what to experiment with at this point.

  19. #19
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    Gobble-gobble

    I had '04 and '06 J7s on a Turner 5 Spot/Pike. I had Gobbling with both (different gen calipers and rotors) but only on the rear. Tscheezy posted some time ago using a dremel to round the edges of the rotors/legs which clip and sometimes actually chip off the edges of the pads. I switched to Magura Marta's and havent looked back since-- no squeal/gobble/leaks. Avid did have great customer support when they used to interact with end users...

  20. #20
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    You can try beveling the leading and trailing edge of the pad a little bit.

    But from the sounds of it, I really just think that either tha pads have worn unevenly, or the pads aren't hitting square. Try replacing the CPS washers with a stack of flat washers.

  21. #21
    Master of None
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    Maybe you aren't giving them time to bed in? The first ride on mine squealed like a stuck pig. I would stop at the mud puddles and rub some mud on the rotor. A couple applications of mud and I was good to go!

    When you look at your worn pads, are they worn evenly? Or can you see some of the pad is shinier than the rest?

  22. #22
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    Lack of bed-in time also occured to me and seemed a likely cause.

  23. #23
    Master of None
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    Another thing I have done in the past is to slip some 600 grit sandpaper between the rotor and the pad while everything is all together. Then turn the tire while lightly squeezing the brake lever and the sandpaper surfaces the pads to be true to the rotor. Do this to both pads.

  24. #24
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    [QUOTE=XSL_WiLL]
    Quote Originally Posted by Jerk_Chicken
    settings don't change based on temps, QUOTE]

    Yeah... Because Hope definitely did some voodoo magic on their brakes so it ignores the boiling point of DOT fluid, brake fade, heat dissipation, and other laws of physics.

    The IS caliper is such a pleasure to work with. Face the tabs, space it out, compatibility issues, etc. More work than is neccesary. Sorry to say this, but if a wrench can't set up a post mount caliper, he doesn't deserve to be building bikes.

    I've run Avid brakes for some time now. I've had a bad piston which allowed dirt into the system, it eventually mucked up the MC. But SRAM took care of me. No company will be able to produce a brake that is 100% problem free 100% of the time. Yes, they did produce some faulty rotors. But I still believe that many of the stuttering issues had/have more to do with setup and break in than anything else.
    I have no idea where you invented this angle from. With respect to temps, it has been referenced here the specific problem. You set the pad distance on the Juicy 7's and then when the temps go to a different range, like the next morning, the pads either rub, or the lever goes to the bar. Incredibly annoying and once again, Avid came up with solutions to problems that didn't exist.

    Additionally, I don't listen to 100% of the things you post here since you admitted to shilling for manufacturers for free stuff. So we can add avid to the list, along with Formula?

  25. #25
    Meh.
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    [QUOTE=Jerk_Chicken]
    Quote Originally Posted by XSL_WiLL
    I have no idea where you invented this angle from. With respect to temps, it has been referenced here the specific problem. You set the pad distance on the Juicy 7's and then when the temps go to a different range, like the next morning, the pads either rub, or the lever goes to the bar. Incredibly annoying and once again, Avid came up with solutions to problems that didn't exist.

    Additionally, I don't listen to 100% of the things you post here since you admitted to shilling for manufacturers for free stuff. So we can add avid to the list, along with Formula?
    Uhm. No. I don't. You're manipulating my words. I've gotten free stuff in the past, but for riding, not for posting on MTBR. And if you ask me, you're the one that raves about whatever product that you are currently riding.

    Additionally, you're wrong most of the time! Ha! Because guess what? You can't set the pad distance. It is a open system, and the pistons are self adjusting. The red knob does not adjust the pads. The red knob only affects the throw/contact point of the lever. And you simply said that settings don't change based on temperature. You had not referenced a specific problem. In addition, that statement is FALSE.

    Perhaps you should learn how to work on bikes. Perhaps you should also get off your high horse and stop being such a pompous ass all the time.

    Unlike you, I do make positive contributions to these forums.
    Last edited by XSL_WiLL; 02-15-2007 at 03:17 PM.

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