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  1. #1
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    adjusting bb7-first timer

    HI everybody, not having a great evening tonight! I got my bike back from the local bike shop after they installed my bb7s. I have been saving and waiting on this for a long time so it's pretty cool to have it back. Unfortunately, after I got the bike home, the rear brake is totally dragging! I mean, almost unrideable. I read online and in the instructions, and have been adjusting the two red knobs for over an hour, with no success. I cannot stop the rotor from dragging! Is there another adjustment knob or screw that I am missing? How can I release tension to stop the rotor from dragging?
    I tried loosening the cable coming from the brake but that had no effect. Thanks so much for any help you have, photos would be a godsend, or a link. I have heard that these brakes are so easy to adjust with no dragging or problems so I was surprised to have so much frustration. thanks guys

  2. #2
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    if your lbs installed them take it back and tell them to fix it. that's unacceptable work. Try that first.

  3. #3
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    yep, you're right jcoffman98, I'm totally taking it back tomorrow. But in the meantime I have to ride to work and then to the bike shop so I can have them look at it. So i'm making adjustments now and other than the two red adjustment knobs, is there another way to stop the rubbing?

  4. #4
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    They're easy to install and adjust. You could make the bike shop do it right on one hand, or learn how to do this sort of thing for yourself and be done with the shop for this kind of frustration.

    From your description that the red knobs do not eliminate the drag no matter what position (both backed off completely?), I suspect you need to realign the caliper, perhaps they didn't tighten the caliper down sufficiently after having gotten them aligned. Which side continually rubs? Inboard or outboard?

    Just follow Avid's installation procedure (if you didn't get the printed version with your brakes, try this http://sram.com/_media/techdocs/BB7%20User%20Manual.pdf ) from step one and follow it to the letter (well you probably don't need to remove and reinstall the rotors).

    If you can't eliminate contact with the calipers/pads it is possible you may need to space the rotor or caliper accordingly.
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  5. #5
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    well there are a couple things, i am no expert on disc brakes having just got back into mountain biking after about 4 year break(i live in a very flat town ). But if the turning the inboard and outboard adjustments all the way out isn't working then you need to re align the calipers. you shouldn't have to back them out all the way anyway.

    this might be a silly suggestuion but try reseating your rear wheel first to make sure its centered properly.

    you can align the calipers by loosening the cps bolts (the ones connecting the brake from adapter not adapter to frame) and realigning this is in the avid instructions. Some people use feeler gauges or business cards at this step to center the caliper.

    heres a video http://www.youtube.com/watch?v=x1kezXQVnLY from avid tech support

    other than that the rotors might need truing but make your lbs do that for sure. My roundagon rotors where really out of true compared to my g2 and g3 on my elixirs.

    on the bb7 (as opposed to hydros) only one pad moves the outboard, so the inboard needs to be really close to rotor you dont want it to deflect the rotor when the brake is applied.

    I am guessing though you alignment is bad.

    hope this helps.

  6. #6
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    Back off the two bolts holding the caliper onto the carrier then clamp down on the brake levers. With the levers squeezed tighten the bolts back up. That should help to center the caliper on the rotor.

  7. #7
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    agreed learning to adjust them yourself is somthing you should do. but if he paided good money to get them installed they should do it right or at least let them know they did a crappy job.

  8. #8
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    Quote Originally Posted by jcoffman98
    agreed learning to adjust them yourself is somthing you should do. but if he paided good money to get them installed they should do it right or at least let them know they did a crappy job.
    I agree.

    I'm also about to get my bike back from the shop since I had them setup some new BB7s and install the cables and cable housings. I'm confident that they will do a good job since they've been pretty good with my bikes.

    I had actually already mounted the calipers and the new levers myself, but when it came time to cut the new housings/cables, I decided to back off and take it to a professional. I've ruined cables in the past because I managed to do stupid things....but not this time!

  9. #9
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    thanks a lot memphisr32. I tried your technique and it's much better than it was before.
    thanks a lot. there is still dragging though, it is on the outboard side farthest away from the tire, this is where the rubbing seems to be. i am fine until step 5, align the caliper. i am turning both knobs until the rotor is snug between them (can't move), then clamping the brake, and tightening the cps. then I back them off a few turns, and I still have rubbing, and then I get frustrated again. any thoughts in the next 30 min or so before i go to sleep mad that would be great. thanks again for your help at this late hour. i had so much to do and have instead been worrying about this brake issue that I just paid the shop to take care of!!!!!!!!!^&%^&$

  10. #10
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    Quote Originally Posted by MemphisR32
    Back off the two bolts holding the caliper onto the carrier then clamp down on the brake levers. With the levers squeezed tighten the bolts back up. That should help to center the caliper on the rotor.
    Not a good way to align a BB7. Best to use the 1/3 - 2/3 spacing within the caliper body and using the pad adjusters to center the caliper, as per the Avid installation instructions.
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  11. #11
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    Quote Originally Posted by Bikinfoolferlife
    Not a good way to align a BB7. Best to use the 1/3 - 2/3 spacing within the caliper body and using the pad adjusters to center the caliper, as per the Avid installation instructions.
    Slightly off topic, but just a quick question. Is the 1/3 - 2/3 spacing for better modulation?

  12. #12
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    Pretty much yes....

    That and the outboard pad has more and finer adjustment than the inboard pad. Adjusting the caliper slightly outboard as Avid recommends takes advantage of that wider range of finer adjustment and allows you to set up your pad initial contact point almost anywhere in the range of the lever pull. You can set up anything from an on/off feel to not gettting full braking power until the lever bottoms against the grip (not recommended but doable), or anything in between. That range of adjustment combined with the leverage adjustment of a Speed Dial brake lever can give you virtually any feel that you want out of the brakes.

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  13. #13
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    Don't forget to pull the brake lever after turning the outboard knob counter-clockwise. Otherwise the outboard pad will not be pushed in it's new position and you think something is wrong.

    As I understand it the 1/3 to 2/3 thing is that the brake is centered at the moment where you apply the brake - then the disc is pushed to the middle of the caliper. Otherwise it could happen that the rotor will be pushed against one side of the caliper and drags there.

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