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  1. #1
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    BB7 install with 185mm rotors - one side I can't adjust properly...

    So I ordered 185mm rotor & BB7 kits from Jensens for my Recumbent trike.

    I installed them using both front brackets, just like the bb5's and 160's I removed.

    Now, here is the problem, I have one adjusted and it spins freely without singing.

    The other, sings even with one side backed out - the outside side has plenty of room. Do I need to bend the mounting bracket? Everything is snugged down pretty tight...
    1993 Cannondale T700 - 1994 Specialized Rockhopper - Actionbent T1 (Electrification in progress!)

  2. #2
    Global Warming Witness
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    I'm not "seeing" what you mean 100%, but couldn't it be the calliper which needs adjusting, if you can't get the rotor through there without it making any noise? I assume that you've backed off the pads on both sides.

    In any case, unless you've banged up the mounting bracket in the past, which could possibly account for it needing bending now, don't try adjusting your brakes by bending anything.

  3. #3
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    Correct, with both pads backed all the way into the caliper, the rotor still provides a bit of braking and noise.

    As far as I know, it's never been banged, and I don't like last ditch "Hit this with a hammer" solutions. Just can't figure out why one will install and work while the other rubs even with the pads all the way out.
    1993 Cannondale T700 - 1994 Specialized Rockhopper - Actionbent T1 (Electrification in progress!)

  4. #4
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    look for where it is rubbing

  5. #5
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    Warped rotor.

  6. #6
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    Don't think it's a warped rotor - as it makes contact during most of the rotation.

    I'm starting to think it is the mount. Looking at it straight on it looks like it's been bent inward a bit. Esp compared to the mount on the other side of the trike.

    Haven't taken any corrective measures yet, but will take a closer look tonight.
    1993 Cannondale T700 - 1994 Specialized Rockhopper - Actionbent T1 (Electrification in progress!)

  7. #7
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    Quote Originally Posted by corkscrew View Post
    I'm starting to think it is the mount. Looking at it straight on it looks like it's been bent inward a bit. Esp compared to the mount on the other side of the trike.
    Even if the mount was slightly bent inwards the BB7 should be mounted with the CPS/Tri Align washers that allow the caliper position to be mounted on a tilt if needed.


    Quote Originally Posted by corkscrew View Post
    Don't think it's a warped rotor - as it makes contact during most of the rotation.
    If the rub is coming from the inside pad and if the caliper can't be positioned inwards any more, the rotor can be shimmed outwards on the hub to stop rubbing.
    Last edited by cobba; 05-25-11 at 10:12 AM.

  8. #8
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    You might consider shimmying the mounts with shaved rubber washers.

  9. #9
    coprolite fietsbob's Avatar
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    Good start over step:, loosen the "postmount" bolts that hold on the caliper
    to the adapter,
    grip the brake lever, to have the caliper grip the disc,
    then re-tighten those bolts.

    thats going to align the caliper to the disc. ..

  10. #10
    Senior Member BCRider's Avatar
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    Because it's a trike do you have to use the mounting bracket on the "wrong" face of the adapter on one side? If so it's possible that the caliper mounting holes are not centered in the thickness so you are not able to get the one caliper to adjust inwards enough for the inside fixed pad to be clear of the rotor.

    Or it could be a number of other issues. I'd start by measuring the rotor face to ISO bracket on the frame on each side. If both are the same spacing then it's the new caliper size adapter bracket is not symetrical and you'll need to either make it "thinner" or to slightly elongate the side to side adjustment slots in the caliper body to allow for the extra half millimeter it sounds like you require. If the ISO mount points on your frame are not equidistant from the rotors then you'll need to figure out why. Is it the frame that is tweaked or is the offset on one wheel different from the other or is it something else? That part is up to you to determine.
    Model airplanes are cool too!.....

  11. #11
    Senior Member jchabalk's Avatar
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    the first time i set up a new frame with disc brakes i spent most of an afternoon screwing around with the brakes. i was having problems exactly like what you're describing. the calipers were rubbing pretty badly most of the time.

    since i had a good shop within walking distance and some errands to run i brought it down there. The mechanic got it all fixed for me - he said the disc tab wasn't aligned, it was off a little and that was causing the problem. he prepped it, did a small amount of filing and the brake's been good since.

    so much for QC

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