AVID BB7: extremely frustrating- Mtbr.com
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  1. #1
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    AVID BB7: extremely frustrating

    my BB7 on the front is very noisy, and CRC, who I bought it from, sent me some organic pads to try to fix the noise.

    I have now spent 2 whole days trying to get it set up right. It was never very good from new, but now I just can't get it set up so it doesn't drag.

    I pulled it apart, cleaned it, it's operating very smoothly, and there's a teensy bit of runout in the disc, but not a lot IMHO, BUT, either it drags, a lot, or, if set up so no drag, the lever goes all the way in to the bar.

    There are 2 ways to set this up: 1. using the Avid instructions, ie, you adjust the pads in (yes, I got the 2/3 to 1/3 thing right) then tighten the CPS bolts, and back off a bit.

    Doesn't work. You get the choice: dragging or no braking.

    The other way is to adjust by ear, get it set up so no drag, then adjust pads.

    Doesn't work. You get the same choice.

    I've watched the videos, d/loaded the Avid technical manual, searched all the forums, etc, etc etc.

    Any suggestions? Preferably from someone who either owns one of these or services them.

    Thanks

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  3. #3
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    cooperplace,

    You didn't mention what you were mounting these on and what brake levers you're using.

    Using the Avid instructions has always worked out well for me. When you're doing the step to get the alignment set up, are you cranking the red adjustment dials all the way down to clamp the rotor?

    If not, what you need to do is have the CPS bolts loose. Turn the inboard knob until it has pushed the caliper into the 2/3 1/3 position. Then, turn the outboard knob until has firmly clamped the rotor. Now tighten the CPS bolts down and tighten the cable down so there is no slack. If you pull on the brake lever, it shouldn't budge. Now, back the red knobs out 2 or 3 clicks each until you get the desired clearance. It should work fine now.

  4. #4
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    DITTO!! When i first got mine I just set them up without reading the instructiona nd they work pretty good, but I got slight rub and didn't find them all that great, but once I follwed the U-tube video and did the 2/3 - 1/3 set like Fubar mentioned they were fantastic. As to pads, yeah, for some reason even using G2 rotors my front made a terrible noise when gently braking( non when applying full on), switched out to organic and no noise.

    Quote Originally Posted by Team Fubar Rider
    cooperplace,

    You didn't mention what you were mounting these on and what brake levers you're using.

    Using the Avid instructions has always worked out well for me. When you're doing the step to get the alignment set up, are you cranking the red adjustment dials all the way down to clamp the rotor?

    If not, what you need to do is have the CPS bolts loose. Turn the inboard knob until it has pushed the caliper into the 2/3 1/3 position. Then, turn the outboard knob until has firmly clamped the rotor. Now tighten the CPS bolts down and tighten the cable down so there is no slack. If you pull on the brake lever, it shouldn't budge. Now, back the red knobs out 2 or 3 clicks each until you get the desired clearance. It should work fine now.
    One day your life will flash before your eyes, will it be worth watching??

  5. #5
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    I'm not understanding how you can go from getting drag to no brake force with the BB7's. Sounds impossible to me. The inboard/outboard adjustments are made in very small increments. might be a dumb question but when you are setting them up, prior to adjusting the calipers and aligning the system, are you loosening the cables first and waiting until the last step to attach cables? If not, this is your problem. Are the rotors severly warped?

    start from scratch.
    1) LOOSEN the cable clamp bolt on the caliper.
    2) set up the lever so that the barrel adjuster is turned all the way inward. then, turn out 1 full turn.
    3) make sure the rotors are true. true them if needed. easy pressure needed here.
    4) loosen CPS bolts
    5) adjust pads so that INNER pad is 2/3 out compared to Outer pad, 1/3
    6) make sure step 5 "locks" caliper to the rotor.
    7) tighten the CPS bolts. alternate between the two until they are fully tightened. the last few turns of the bolts should be made while holding the caliper and feeing for movement. rarely happens but it can if you've over torque the bolts.
    8) loosen pad adjustment knobs one click at a time until the rotor doesn't rub.
    9) attach Cables AFTER the calipers are set up.
    10) use the barrel adjusters on the levers to fine tune lever pull.

    Keep in mind that the rotors and pads will need to bed in before full braking power is reached. By following the above method, I don't see how the system can go wrong unless the caliper actuating arm isn't fully retracting after you release the lever. in that case, either you didn't wait to attch the cables until the end and they are too tight or there is a problem with the bearings in the caliper. in which case, return them to CRC.

  6. #6
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    add this to step #8: turn outer pad adjustment knob first so it is far from touching the rotor. then work on getting the inner pad as close to the rotor as possible without rubbing. Once you do this, dial in the outer knob until it barely rubs. turn one click outward and it shouldn't rub then.

    remember that BB7's only actuate the outer pad when you pull the lever. if the inner pad is too far from the rotor you will get shitty braking because the outer pad cannot push the rotor into the inner pad with enough force to effectively stop the wheels. this is the reason why you set them up with the inner pad closer to the rotor, relative to the center-line of the caliper.

    let us know if this doesn't work.

  7. #7
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    I recently finished a build from the frame up of a Niner MCR. I went with BB7s, Speed Dial levers and Ripcord Jagwire cables which run uninterrupted to the brakes. I had absolutely no trouble dialing in the rear; it was actually stupidly easy, no rubbing at all on the first try.

    The front was a different story. I had a hard time getting it set up so that it wouldn't rub; I kept loosening the CPS bolts and trying to position it again. If I opened up the Outboard pad adjustment so that I was finally free of rubbing then there was no braking force. What I did to solve the problem was this:

    1 - [With my front wheel off & the CPS bolts loose] I opened the Outboard adjuster fully so the pads were as far apart as possible.
    2 - I used the supplied Allen wrench to adjust the Inboard dial so it was centered [that is to say I arbitrarily rotated the dial in one direction until it was maxed out, no longer made equal click stops, then I counted the number of clicks in the opposite direction until it was maxed out again before backing off half that number.] At this point the Inboard dial can adjust an equal number of units (click stops) in either direction clockwise or counterclockwise.
    3 - Put my wheel back on the bike and started adjusting the Outboard dial to bring the pads together to completely immobilize the rotor. I found that I had to adjust the Inboard dial to allow for this to happen. During this process the caliper is free to move with the CPS bolts loose.
    4 - Once the pads completely immobilized the rotor I tightened down the CPS bolts.
    5 - I backed off the Outboard dial to open the pads a little.
    6 - I adjusted the Inboard dial to achieve the 2/3 to 1/3 spacing.

    After that I had no problems with rubbing, no problems with brake force either. And thankfully with the stock pads and the stock 160mm rotors I've never had squealing noise problems either. I think my original problems got started when I tried repeatedly to get the 2/3 - 1/3 spacing correct prior to tightening the CPS bolts. After multiple tries the Inboard dial was far out of center meaning I had very little adjustability in the direction I needed it once I thought I got things right. As a result I was opening up the pads (to get rid of the rubbing) to try and compensate for the lack of adjustability on the Inboard side.

    Personally I think that it is meaningless to try to adjust the 2/3 – 1/3 spacing prior to tightening the CPS bolts for the first time. The CPS bolt itself is smaller in diameter than the washer’s inner diameters and the caliper bolt holes. You might tilt/hold the caliper all the way in toward the wheel and then start the spacing adjustment then during the process of tightening the bolts you could slightly shift the caliper so it is held away from the wheel where it gets tightened down in that position. The difference would only be millimeters but so is the spacing gap.
    Last edited by Van-D 2-Niner; 11-11-2010 at 02:29 PM.

  8. #8
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    Van-D, was the rubbing constant the entire rotation of the rotor or was it due to a warped rotor?

  9. #9
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    Quote Originally Posted by mnigro
    Van-D, was the rubbing constant the entire rotation of the rotor or was it due to a warped rotor?
    The rotor seemed very very close to true, it might have been the slightest bit out of true but not enough to worry about straighten it. It was brand new upon install. During the adjusting period I would hear a constant rubbing sound (light but present) and I would adjust the Outboard one click stop at a time and it would get uniformly better until the wheel would spin with no rubbing. And once I took care of my issue with the Inboard adjustment dial I was able to back off the Outboard only 2-3 clicks from fully immobilizing the rotor (as per the Avid instructions) without having a rubbing issue.

  10. #10
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    The weak link in the Avid system (not just the BBs but all of their brakes) are the CPS washers. They usually have a poor surface finish that does not allow them to make the small adjustments needed. Giving the conical washers a light sanding followed up with a very light greasing will help some. Be careful not to apply too much grease as it may run out onto the rotors or pads and wipe off any excess.

    If you can find a suitable washer alternative, get rid of the awful CPS ones. If Avid's calipers just sat square to begin with, they would have many fewer complaints of noise and power loss. I swear the CPS system causes more problems than it fixes, frames are being held to much higher tolerances these days and most bike shops have the tools needed to face brake mounts anyway. Avid would make me much happier if they had adapter kits available to remove the CPS system if you so choose.
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  11. #11
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    I always thought the surface finish was to help the stack retain its position. Have you expereinced any shifting under load?

  12. #12
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    Quote Originally Posted by zebrahum
    The weak link in the Avid system (not just the BBs but all of their brakes) are the CPS washers. They usually have a poor surface finish that does not allow them to make the small adjustments needed. Giving the conical washers a light sanding followed up with a very light greasing will help some. Be careful not to apply too much grease as it may run out onto the rotors or pads and wipe off any excess.

    If you can find a suitable washer alternative, get rid of the awful CPS ones. If Avid's calipers just sat square to begin with, they would have many fewer complaints of noise and power loss. I swear the CPS system causes more problems than it fixes, frames are being held to much higher tolerances these days and most bike shops have the tools needed to face brake mounts anyway. Avid would make me much happier if they had adapter kits available to remove the CPS system if you so choose.
    agreed. I replaced my CPS stacks with flat washers after double-checking that my mounts were square and straight. It simplified alignment by a huge degree and made them so much nicer to work with

  13. #13
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    Quote Originally Posted by gte819s
    I always thought the surface finish was to help the stack retain its position. Have you expereinced any shifting under load?
    I check all the brake mounting bolts pretty frequently and they've never slipped on me. That being said, I didn't smooth them down to mirror finish or anything just enough to reduce their tendency to always slip back to the same position over and over again.
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  14. #14
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    Quote Originally Posted by zebrahum
    The weak link in the Avid system (not just the BBs but all of their brakes) are the CPS washers. They usually have a poor surface finish that does not allow them to make the small adjustments needed. Giving the conical washers a light sanding followed up with a very light greasing will help some. Be careful not to apply too much grease as it may run out onto the rotors or pads and wipe off any excess.

    If you can find a suitable washer alternative, get rid of the awful CPS ones. If Avid's calipers just sat square to begin with, they would have many fewer complaints of noise and power loss. I swear the CPS system causes more problems than it fixes, frames are being held to much higher tolerances these days and most bike shops have the tools needed to face brake mounts anyway. Avid would make me much happier if they had adapter kits available to remove the CPS system if you so choose.
    how do you check the calipers are square? this is real interesting and something i'm going to need to try.

  15. #15
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    Quote Originally Posted by William_Cannon
    how do you check the calipers are square? this is real interesting and something i'm going to need to try.
    Well, if you're just checking your calipers with the CPS washers installed then it's a mostly visual check. Get the caliper lined up and tightened down, then you'll want to visually inspect the gap between the rotor and pads on both side. If the gap is larger at the top or bottom, then you need to realign the caliper to square it off to the rotor. Another way which is usually harder to see is that you can squeeze the brake lever while watching the rotor. I usually do this to check if the rotor is twisting like an S as it goes through the caliper, but sometimes you can see if the braking surface is being bent as it is pinched. It's certainly much harder to see than just looking at the pads though. Holding up a piece of paper behind the pads may help add contrast and make things easier to see.
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  16. #16
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    One thing that's important when you're setting up used brakes is to start with brand new pads. As the pads wear down, they do not wear evenly accross the surface of pad, so you end up being unable to set the rotor gap to be parallel to the rotor. Brand new pads are critical to the avid instructions.

  17. #17
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    Do a search for Squash here for the Avid BB7's. Its been posted many, many times.

    He offers excellent information. I follow his tips/tricks to setup BB7's. Works perfect each and every time.

  18. #18
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    I did a search for Squash, but I suck at the internet and couldnt' find it...

  19. #19
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    Quote Originally Posted by William_Cannon
    I did a search for Squash, but I suck at the internet and couldnt' find it...
    Go to his post here: http://forums.mtbr.com/showpost.php?...3&postcount=13

    Then you can click on the setup link that I posted from the Park web site. These instructions should help. Good luck. I love my BB7's.

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