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  1. #1
    mtbr member
    Reputation: HighSpeedChase's Avatar
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    Newb needs new brakes...

    Hey all,

    So I have a 2011 Rockhopper Expert 29er and my brakes have just been giving me all sorts of problems. They are Shimano br-m505. My LBS said they are pretty much really low grade hydro brakes. The front works decent but the rear has a lot of vibration and howling (I'd even call it screaming). I've had them look at it 3-4 times now to no avail and just want to bite the bullet and get some new brakes.

    I don't want to spend too much money on them as I'm saving up for a better bike, I was curious on your opinions on these choices I've narrowed down to myself. Or maybe you'd have a better recommendation?

    Avid Elixir 5 Disc Brake - Gloss Black | Buy Online | ChainReactionCycles.com

    or

    Avid Elixir 3 Disc Brake - Grey 2013 | Buy Online | ChainReactionCycles.com

    I'm not what the big difference between the 3 and 5's are. Can anyone help me out?
    Ride: 2014 Yeti SB66AC

  2. #2
    mtbr member
    Reputation: 006_007's Avatar
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    Personally those Avids are not a whole heck of a lot better then what you currently have on there - You think your current brakes "howl" wait till you try a set of avids. If you were looking to upgrade the new shimano SLX discs are the absolute minimum I would start with:

    Shimano SLX M666 Disc Brake | Buy Online | ChainReactionCycles.com

    And also consider the new Shimano XT as well.

    Shimano XT M785 Disc Brake | Buy Online | ChainReactionCycles.com

  3. #3
    Just a flesh wound
    Reputation: Prophet Julio's Avatar
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    What kind of rotor do you have? It may be that you just need a different rotor or new pads. Some cheap rotors are for resin pads only and if you have sintered pads..I had a similar issue some years ago on a friends bike and changing the rotor size fixed it. There was some harmonic resonance thing going on and changing the rotor size was the trick. Pads and rotors are cheap.
    My name is Chris and I ride a Prophet 650b with a Lefty.

  4. #4
    Cow Clicker
    Reputation: wmac's Avatar
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    Before you spend any money, read this: MTBR.com Brake Time Forum - Disc Brakes FAQ

    "Why do my brakes squeal and how can I fix it?

    First and foremost there is NO disc brake which NEVER squeals and NO disc brake type which ALWAYS squeals.* Also there is no specific area where brakes have more problems. From super dry Scottsdale Arizona to wet Seattle there will be a few screaming brakes in every area of the country. Some brakes*seem to have more problems than others but in general it's one of the following :

    Dirty ( oily ) rotors - clean thoroughly with Isopropyl Alcohol
    Dirty ( oily ) pads - clean with Isopropyl alcohol, then use emery paper and scuff the pads. Remember they need to be newly bedded in, so the first stops are not what you expect. If braking power is drastically reduced, replace pads with new ones.
    Loose rotors and loose calipers - tighten them up.
    Loose cones in the hub - again tighten them.
    Loose spokes - sometimes you can detect this if you rub a little grease exactly where the spokes are crossing/touching each other. If the noise changes, then you need to retighten the spokes.
    Loose quick-release - especially on alloy dropouts the q/r sometimes works itself into the alloy, the tension gets less and the axle starts vibrating.
    Loose suspension bolts - seems to be a problem on the older I-drive bikes, but not only them. Check the owners manual for proper torques.
    Loose Headset - adjust to specifications.
    Loose .... loose... loose ANYTHING. Yes even a loose saddle can make a noise if vibrated by the brakes.
    Incorrect alignment - use a Gnann-o-mat or Hope Spot tool to machine the tabs or use the CPS on Avid brakes.
    But no matter what, some brakes just squeal.* It seems like a lot of the problem comes from other parts of the bike where a harmonic vibration set up by the brakes manifests itself in an audible squeal.* You have to work case by case, find the vibrating part and somehow cure it.* I once had a squealing brake that was instantly cured by switching to a rotor from another manufacturer."

    It's possible you did not bed them in properly which makes this happen. Clean then and try again
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  5. #5
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    Thanks for all the in put!

    It seems after alot of trial and error and investigation I have a Shimano BR-M445 calipers and M505 levers.

    Anyway, I've tried everything imaginable and what I've read on here. Cooked, brake pads, New Brake Pads, Aligned Calipers, Clean Rotor using denatured alcohol, sanded rotor, sanded brake pads, tried a new rotor, cleaned inside the caliper, bled brakes, bedded brakes, tightened everything.

    After all this I still have this god awful howl and vibration. So I'm pretty much fed up and think I will just save up the cash for some nice high end brakes.
    Ride: 2014 Yeti SB66AC

  6. #6
    Just a flesh wound
    Reputation: Prophet Julio's Avatar
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    Try a different sized rotor, a round one without any waves. If you have a 180mm, go to 160. You will need a new caliper adapter, but they are cheap.
    My name is Chris and I ride a Prophet 650b with a Lefty.

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