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  1. #1
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    Avid BB7 Rotor Rubbing

    Hello guys,
    recently i installed a pair of bb7s mtn on my trek 8.3ds with pretty good results. However i've been having trouble with the front brakes. I did install the rotors on my wheels from the brakes.

    When i lean the bike to one side while riding or lean my weight to the front wheel i can hear the brakes rubbing the rotor slightly. When i sit back and stay straight up they are fine. I can tell the rotor moves side to side slightly when i spin the wheel on the bike and watch the distance between the pads.

    Is there a way i can correct the rotor so it doesn't move when i lean on it or do i need to dial the pads out further and deal with having to pull my brake lever to my handle bar to engage the front brakes.

    Thanks for any replies!

  2. #2
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    Sounds like the wheel isn't on tight. Moving your weight around on the bike shouldn't effect the rotor rubbing. It either rubs all the time or does not.

    Something isn't right.
    13 Lenz Lunchbox punkass

  3. #3
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    Alright let me take a look at it for a second. That would make the most sense though.

  4. #4
    Big Gulps, Alright!
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    The fork on the 8.3DS isn't a very stiff chassis. It's mostly likely lateral flex causing the rotor to rub on the pads. Not much you can do short of making sure the QR is tight, and perhaps dialing the pads out. The two extremes are live with it, or replace the fork.

  5. #5
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    What do you mean by QR? I tightened the wheel on there as much as i could and made sure it was aligned well and it still rubs if i lean to either side.

    Also if I were to replace the fork what would be a good choice that is not overly expensive with the same lockout feature my forks have?

  6. #6
    ballbuster
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    Welcome to BB7s. Rotor rub city. You'll get to know those goofy red knobs well.

    Something that often gets overlooked in the instructions (and not explained very well) is that you use the lever or caliper barrel adjusters to take up the cable slack, and that is it. You don't use them to adjust the pad free travel gap. You use the red knobs on the calipers for the free travel gap.

    Sounds like you need to true your rotors a bit for starters as well. Just look for the spots that bend one way or the other and tweak them back with a crescent wrench.

    Also, be sure you wheels are all the way home in the dropouts. That is, if you put a wheel on with the bike upside down or whatever, turn the bike over and open and close the QRs so the axle goes all the way home.

    Also check for hub bearing play. If the wheels are in the frame and QRs are closed and snug, you should not feel any tap dance play in the wheel if you wiggle it side to side.

  7. #7
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    Yes I found out quickly the instructions provided in box are terrible so I followed parks setup instructions.
    So your saying I should not be using the lever barrel adjuster to close the gap between the rotor and pads. That I didn't know.
    I will have to try to tru the rotor slightly because it certainly does move side to side a bit.

    I did all the rest of the things you said I made sure the front wheel was seated properly with not play in the hub.

  8. #8
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    Quote Originally Posted by Berkley View Post
    The fork on the 8.3DS isn't a very stiff chassis. It's mostly likely lateral flex causing the rotor to rub on the pads. Not much you can do short of making sure the QR is tight, and perhaps dialing the pads out. The two extremes are live with it, or replace the fork.
    What Berkley says is 100% correct. Your forks are flexing causing the caliper to rub the rotor. Can I ask how much you weigh?

    That bike uses a 63mm fork, which is more for road comfort than off road riding. If you are riding primarily on the road or gravel surfaces, I would actually switch to a rigid fork.
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  9. #9
    Always Learning
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    Quote Originally Posted by pimpbot View Post
    Welcome to BB7s. Rotor rub city. You'll get to know those goofy red knobs well.
    This is my 11th season riding with them, and I have to disagree. No rotor rub on my set ups.

  10. #10
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    Quote Originally Posted by BruceBrown View Post
    This is my 11th season riding with them, and I have to disagree. No rotor rub on my set ups.
    Same here, nothing wrong with BB5's, been running them for about 8 years on one of my bikes and never had an issues, for me they have had less maintenance than my hydraulics. Yes, about once a month or so I might check the pad gap and make a 10 sec red knob adjustment but that's pretty quick and easy.

  11. #11
    transmitter~receiver
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    The same thing happens on my Big Dummy, which has a pretty damn stout fork and 26" wheels.
    The only way I could stop it was to increase the gap. The rotor is as true as the day is long.
    The one-side-travel design of the BB7 certainly doesn't help.
    Quote Originally Posted by pvd
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  12. #12
    psycho cyclo addict
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    Quote Originally Posted by BruceBrown View Post
    This is my 11th season riding with them, and I have to disagree. No rotor rub on my set ups.
    +3 - BB7's have been stellar w/ no rub on my rigid SS 29er (even with a "noodly" steel fork as my cronies with carbon ones tell me )

  13. #13
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    Quote Originally Posted by pimpbot View Post
    Welcome to BB7s. Rotor rub city. You'll get to know those goofy red knobs well.

    Something that often gets overlooked in the instructions (and not explained very well) is that you use the lever or caliper barrel adjusters to take up the cable slack, and that is it. You don't use them to adjust the pad free travel gap. You use the red knobs on the calipers for the free travel gap.

    Sounds like you need to true your rotors a bit for starters as well. Just look for the spots that bend one way or the other and tweak them back with a crescent wrench.

    Also, be sure you wheels are all the way home in the dropouts. That is, if you put a wheel on with the bike upside down or whatever, turn the bike over and open and close the QRs so the axle goes all the way home.

    Also check for hub bearing play. If the wheels are in the frame and QRs are closed and snug, you should not feel any tap dance play in the wheel if you wiggle it side to side.
    Rotors are either true or not, moving your weight around on the bike doesn't change that. OP clearly states it rubs when they lean on the front, that has nothing to do with true.
    13 Lenz Lunchbox punkass

  14. #14
    Nouveau Retrogrouch SuperModerator
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    Avid BB7 Rotor Rubbing

    Quote Originally Posted by TwoTone View Post
    Rotors are either true or not, moving your weight around on the bike doesn't change that. OP clearly states it rubs when they lean on the front, that has nothing to do with true.
    He also said he can see the rotor wobble when he spins the wheel. That has everything to do with true.
    Quote Originally Posted by OpenTrails View Post
    When i lean the bike to one side while riding or lean my weight to the front wheel i can hear the brakes rubbing the rotor slightly. When i sit back and stay straight up they are fine. I can tell the rotor moves side to side slightly when i spin the wheel on the bike and watch the distance between the pads.
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  15. #15
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    I have been using bb7s for a few years now and I think it's probably that the rotor is slightly out of true. My rear wheel has had this in the past as I lean into a right sided turn. The rotor was trued and haven't had a problem since. Since you installed them yourself, my guess is that the rotors were not true out of the box, which is common. The other thing you might check is that the pads are seated flush in the caliper, no dirt or grit that kicks the pad out slightly. Should be a simple problem to fix.
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  16. #16
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    Quote Originally Posted by Vespasianus View Post
    What Berkley says is 100% correct. Your forks are flexing causing the caliper to rub the rotor. Can I ask how much you weigh?

    That bike uses a 63mm fork, which is more for road comfort than off road riding. If you are riding primarily on the road or gravel surfaces, I would actually switch to a rigid fork.
    6'2 220lbs. Is there a decent fork that won't cost more than the bike itself did?

  17. #17
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    I think truing the rotor may help alot because when I lean the bike and it runs it's only in a certain spot. Which I assume is where the rotor is out of tru. Because the rotor doesn't rub constantly when I lean only specific spots

  18. #18
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    Once you've trued the rotor, gotten a stiff fork, made sure the clearances are correct, adjusted the hub to reduce bearing play and tightened the QR like mad, you might find that a slight bit of rubbing when you corner hard isn't the end of the world.

    About the clearances, one very common mistake is to center the rotor between the pads. Rather run the inside pad (stationary, large knob) as close to the rotor as you can without rubbing, then adjust the attack point with the outer pad (the one that moves and has a smaller red knob). And yes, use barrel adjusters to reduce cable slack only.

  19. #19
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    Some advice as rotor rub was driving me crazy and still creeps up occasionally.

    1. Sit on the bike and have someone tighten the QRs.

    2. Rotor may be out of true. It may not be the source but it doesnt hurt to check how much "wobble" you actually have.

    3. Start from scratch. This guys obnoxious but its a very thorough install guide. Highly suggest a long T25 for this.
    Avid BB7 Disc Brake set up and tuning. | Two Wheel Blogs

    4. How much do you pull your brakes before they engage ?
    I wanted mine to lock up strength with a simple tug. I had to be be wiling to give it some breathing room. Depending on your levers (speed dial 7 for ex) you can adjust the angle of the pull without actually loosening the cable.

  20. #20
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    Quote Originally Posted by OpenTrails View Post
    I think truing the rotor may help alot because when I lean the bike and it runs it's only in a certain spot. Which I assume is where the rotor is out of tru. Because the rotor doesn't rub constantly when I lean only specific spots
    That could be. I have had Avid rotors that are brand new, be out of true. Also, at 220 lbs, I would not doubt for a second that you have fork flex and that is the main problem. I unfortunately don't have any ideas of a good fork to replace it with. Sorry!
    On MTBR, the reputation is infamous.

  21. #21
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    Thanks for the replies I will have to true the rotor and start with the caliper alignment and such. Ill post results.

  22. #22
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    Well I trued the rotor, started from scratch on installation and this time back the pads out just a bit more and all is well. Thanks for the help guys.

  23. #23
    Nouveau Retrogrouch SuperModerator
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    Avid BB7 Rotor Rubbing

    Quote Originally Posted by OpenTrails View Post
    Well I trued the rotor, started from scratch on installation and this time back the pads out just a bit more and all is well. Thanks for the help guys.
    Good job.
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  24. #24
    transmitter~receiver
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    Avid BB7 Rotor Rubbing

    Quote Originally Posted by shiggy View Post
    Good job.
    X2

    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  25. #25
    Ahhh the pain....
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    I didn't see it mentioned above but one thing I've noticed is that some QR's have a small plastic shim in them that serves as the friction surface for the cam. That simply adds compliance in the stack and can allow the wheel to move. A better QR (like a hope QR) solves that problem.
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