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  1. #1
    The Green Machine
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    Brake Rub - Caliper seems to be moving...

    I have Juicy 7's on my 06 Stumpjumper FSR Expert. I seem to have problems with the pads touching the rotors whenever I take off the tires, and I am not squeezing the brake levers. This happens more so on the back. It's driving me freakin bonkers!

    Took off tire for some reason or another, put it back and it rubbed. Tried to reset the pistons, that didn't work. Pads are pretty much brand new as the bike is only a month old. Finally unbolted the caliper and put the washers on the reverse side to make the rotor sit in the center of the pads. Spun the tire, rolled great! I store the bike hanging by two hooks, one on the stem, the other under the seat.

    Next morning I check the rotation. Rubbing again ever so slightly on the opposite side that it was rubbing before. I let it be, went for a ride and it was fine when I was done. Took the wheel off again to wash the bike, and clean the cogs, and when I put the wheel back on it rubbed again. I try to tighten to approx. the same torque as it was originally but still it rubs. (Both the wheels quick release and the bolts holding onto the caliper)

    Reverse washer again and it spins free. Took the bike out for a ride just down the street and somehow got a pinch flat. SO, guess what? Took off the tire to repair, put it back and RUBBING AGAIN! Pretty bad this time too

    So, I've tried resetting the pistons and put the tire back on. Spins better, but still touches a little bit. I've hung it up for the night to see if it mysteriously moves back into true.

    Whats going on? I don't see my rotor being warped, pads are new, I don't hit the levers when the tire is off...what gives?

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    It's because you're taking off the wheels and putting them back on. You aren't tightening them exactly the same each time. This causes the axle to sit slightly differently or cocked in the dropouts each time.

    If it's a constant drag, you need to center the caliper still. If it's intermittent, then your rotor needs to be trued. Take the time to set up the calipers to make sure the pad gap is even on each side.

  3. #3
    mtbr member
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    Try tightening the skewers with the bike right side down, wheels on the ground instead of upside down. Then you'll be able to be more consistent with making sure the wheels are sitting in the dropout correctly and settled in. Hope this helps.
    We Ride In God's Country!

  4. #4
    The Green Machine
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    Thanks for the advice. I will try doing it right side down, but man these brakes are finicky as hell. I've noticed that when the rub is very minor, I can tighten/loosen the quick release and make the rub stop, but then other times its just a constant hard rubbing.

    What I don't get is why the rubbing switches sides, I find that very strange. From now on I will try tightening with the wheel on, right side up. I haven't ridden in 10 years and this is my first venture into bikes with disc brakes. I've heard other complaints with the Juicy 7's, does this happen with other brands as well? I suppose they all have their quirks.

  5. #5
    wyrd bi ful rd
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    As what XSL mentioned, whenever you take off the tyre and put them back on again the axel will not be sitting in the same place and so you will need to re-align the caliper.

    But contrary to what little blue suggested, I invert my bike when installing the wheels as gravity is helping me to sit the axel all the way down into the dropout before tightening. Just another way that workls for me.

    Even so, every 3 out of 5 times i will still need to re-align the caliper. Just tell yourself that you will need to re-align the caliper whenever you remove the wheels.

  6. #6
    Meh.
    Reputation: XSL_WiLL's Avatar
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    You may also want to try a good QR. Something like a Shimano XT or the DT Swiss RWS.

  7. #7
    The Green Machine
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    Is there really a difference between quick releases?

  8. #8
    Meh.
    Reputation: XSL_WiLL's Avatar
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    Yes.

  9. #9
    Ride Everything
    Reputation: GRAVELBIKE's Avatar
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    Quote Originally Posted by littleblue
    Is there really a difference between quick releases?
    Yes. Many of the external-cam alloy q/r's won't let you get proper/consistent tension. The two that WiLL mentioned are excellent.
    GRAVELBIKE.COM - ride everything

  10. #10
    mtbr member
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    I found that same thing with the wheel in and out thing. It is down to QR tension variation causing the wheel to shift a bit from it's last position.
    What I was able to do with my rear QR's was to thread a grub screw into the nut end which means that the QR is always threaded in by the same amount. I think there is a manufacturer that actually makes such a thing ?

    Couldn't do this on the front (would have been more use as the front is always out when tansporting the bike in the car) but found that if I pushed the fork down onto the axle a few times before tighteneing the QR it helped centre the wheel. On occasions when the rubbing is a tad too much just hold the disc against the pad that's closest and squeeze the lever hard a few times. This generally allows the pistons to shift about so although the pistons may not be centralised, they are evenly either side of the disc.

    I hope that explains it well enough !!

    Edit - just found it - http://www.1upusa.com/quicknuts.html
    Ride hard dudes !

  11. #11
    Vaginatarian
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    Quote Originally Posted by littleblue
    Thanks for the advice. I will try doing it right side down, but man these brakes are finicky as hell. I've noticed that when the rub is very minor, I can tighten/loosen the quick release and make the rub stop, but then other times its just a constant hard rubbing.

    What I don't get is why the rubbing switches sides, I find that very strange. From now on I will try tightening with the wheel on, right side up. I haven't ridden in 10 years and this is my first venture into bikes with disc brakes. I've heard other complaints with the Juicy 7's, does this happen with other brands as well? I suppose they all have their quirks.
    the rubbing switches from side to side because the wheel is not in the dropouts all the way, when it rubs 1 side its out of wack one way, and when the opposite side rubs its out of wack the other way, the tolerances are pretty tight and it doesnt take very much to be off. also if the qr isnt tight enough or strong enough the wheel will move from riding/ braking
    Ive found some bikes/wheels are worse than others, but the key is to adjust the brakes after you've done everything else listed above

  12. #12
    Make some music
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    Quick Nuts

    Definitely....
    J.O.R.B.A. More than just tm. WWW.JORBA.ORG

  13. #13
    mtbr member
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    I don't know if it could be this but I found this to be an issue for me the other day.

    I accidentally hit the brake lever while the wheel was off and I got rub once I put the wheel back on. So I pulled the pads out and out them back in thinking maybe they came off alignment a little bit, no change. So I pulled them back out and tried to see if the pistons were out a little bit and they were out just a little bit since the moved back in when I pushed on them. Put the pads back in , put the wheel back in and no more rub.

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