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  1. #1
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    Love my 970, HATE the annoying whistling of my rear Formula brake

    Great stopping power. But VERY noisy and a TREMENDOUSLY annoying, intermittent "whistling" noise with the rear brake/caliper when I pedal at slow speeds.

    No noise whatsoever coasting, simply when I pedal. Not when I'm putting down solid power, just when I start turning the pedals. I understand there could be a chance if I'm putting decent power down and maybe the wheel is flexing along with the rotor, but I can get it to 'whistle' when I already have forward momentum and turn the crank with ease. Plus - I'm a whole 135 pounds soaking wet.

    It seems very intermittent, but the consistent factor is pedaling uphill at slow speeds. No rubbing when I put it on the stand. LBS checked it out and seemed fine. When I get on the trail, I start climbing and it's a constant annoying whistling. Yet, it will go away for a few stretches of the time.

    I'm seriously about to take them off the bike and go Office Space postal on them. I have honestly never been more frustrated with a single bike part. The rear brake lever also has a little bit of play and doesn't rebound after squeezed responsively, even after the LBS bled them.

    I've come off Avids (both juicy and elixir) and sacrificed some noise for modulation, but may only go XT in the future. This is just too much...


    Thoughts??? Rocky Mountain PM - have you had any similar feedback from others?

  2. #2
    ups and downs
    Reputation: rockyuphill's Avatar
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    That sounds like a sticky piston and/or a caliper alignment issue, with some pad rub. The wheel and spokes flexing won't affect the hub/rotor/caliper relationship. It'd be worth checking how tight the axle is as well, a 142mm axle shouldn't allow a rotor to be out of square, but it can pull the dropout in toward the hub (and rotor) if it's over or under tight.
    I'm a member of NSMBA and IMBA Canada

  3. #3
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    The Formulas are super sensitive to set up I've found. Cleaning the rotors after each ride with rubbing alcohol and making sure the rotors are completely true helps some, though eventually I ended up switching to organic pads in order to get rid of all the noise.
    Tarekith.com

    '12 RM Slayer70, i9 Torch, Flow EX, XT Brakes, 5050 s3.

  4. #4
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    The Formula brakes on my 2011 Vertex SE annoyed me greatly. However, I have recently come to notice that their noise is dissipating greatly with more break-in.

    So, maybe they do it more when new, and will wheeze less as the pads wear a bit?

    Interestingly, the Formulas on my new Element 26" don't make any noise. A 29er thing?

  5. #5
    Older & Slower
    Reputation: JTeezy's Avatar
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    Organic pads (always helps, but they have gotten so expensive!)...have LBS true rotor (mine did have a wobble in it that made it impossible to silence)...lots of TLC from you on caliper (squeeze brake lever and tighten a bit at a time, alternating between the two bolts...sometimes I have to forget the lever and eye-ball where the rotor sits between the pads). Most of it probably comes down to you finding a way to finesse the caliper.

  6. #6
    BJF
    BJF is offline
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    I absolutely hated the Formula brakes on my 970. No matter what I did they made noises. I finally got sick of them and replaced them with new XTRs. Have not had a single issue or noise in two hundred miles.

  7. #7
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    replace with maguras

  8. #8
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    The best solution is to toss them. I had R1 Forum and brakes and while they were powerful, they just wouldn't stop rubbing. Sold them and went with XTR. Way better brake and lever feel.

  9. #9
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    Ok, finally got this figured out as my LBS has a great mechanic. He cleaned the internals of the brakes, but it seemed like the main issue was that there was too much brake fluid and the pads weren't going all the way back to the starting position... thus not giving very much wiggle room between pad and caliper.

    Thanks for all of the input - appreciate it.

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