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  1. #1
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    BB7 Install Problem

    I'm replacing a broken 2003 front BB7 (160mm) with the 2009 version (185mm). The fork is a '03 marzocchi bomber.

    The problem is that the new rotor rubs on the outer pad even with the outer pad adjuster backed all the way out, and no matter how I slide and tilt the caliper/washer mounting system, I cannot get the caliper far enough out so that the rotor doesn't rub.

    I'm about to give up and remount the new caliper on my old 160mm rotor and mount. Does anyone have any ideas?

  2. #2
    ride
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    Might need to face the disc tabs on the fork. Got pics?
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  3. #3
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    I'm not sure what you mean by face the disk tabs?

    I just tried to install the old 2003 caliper with the new mounting bracket and I had the same problem. Looks like it's the mounting hardware (IS mounts, I forgot to mention)

    I'll work on getting a pic now

    Last edited by lostinNH; 05-01-2009 at 01:03 PM.

  4. #4
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    http://www.flickr.com/photos/37967387@N02/3492358060/

    Can't seem to get it to host the image, but here's a link to the pic on flickr

  5. #5
    ride
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    Facing the disc tabs means machining them to be parallel to each other and square to the hub axle. It also removes material from the fork tab. If the old adapter works, though, just use the older adapter. It is probably a bit thinner than the new adapter.
    Redstone Cyclery
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  6. #6
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    Quote Originally Posted by lostinNH
    I'm not sure what you mean by face the disk tabs?
    Facing the disk tabs means removing frame material so that the caliper will fit / align properly.

    I wouldn't do this, especially since the old bracket worked. You might think about modifying the bracket though. Also consider using the old bracket with the new caliper.

  7. #7
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    Thanks for the reply. I don't have an old adapter for the 185mm, just for the 160mm. I managed to stump the SRAM people on the phone as well. Looks like I'll have to go to my dreaded LBS and see if my new adapter is an outlier or something.

    Can disk tabs be faced with a standard file? I actually have access to a full machine shop as well.

  8. #8
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    Yes, you can face the disc mounts with a standard file. As you are using the Avid CPS disc adapter (with the conical washers), this will account for any imperfections caused by your handywork provided they're not too great.

    Alternatively, you could just add a 1mm shim washer onto the wheel axle.

  9. #9
    ride
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    If your local shop is a good one, they should have a tool to face the tabs. Don't worry about removing material from the fork, it's more common than you would think. It's hard for fork factories to QC disc tabs with a casting like that. I've removed 1/2 a millimeter of paint before with a facing tool.

    I would not recommend shimming the axle and spreading the fork.
    Redstone Cyclery
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  10. #10
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    I am using the CPS adapters (i think...the bolts that hold the caliper on the adapter have 2 conical washers each). I'll also double check with the lbs.

    I really appreciate the help guys -- i was pretty bummed to take a day of riding adjusting a simple brake with no success...

  11. #11
    PCC
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    Is there any possiblity that you installed the adapter backwards? Just asking.

  12. #12
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    PCC -- I'm pretty sure it only fits over the rotor one way. The way I have it, the letters "185 f" face the wheel and the arrow points up, away from the ground, and the large caliper knob faces the wheel as well. Can't seem to find any pics of the 185mm front to verify, thought.

  13. #13
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by lostinNH
    Thanks for the reply. I don't have an old adapter for the 185mm, just for the 160mm. I managed to stump the SRAM people on the phone as well. Looks like I'll have to go to my dreaded LBS and see if my new adapter is an outlier or something.

    Can disk tabs be faced with a standard file? I actually have access to a full machine shop as well.
    Do not file the fork, file the caliper mount (adaptor). You can easily do it with a hand file. If you screw up, just replace the adaptor and you have not damaged the fork.
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  14. #14
    rebmem rbtm
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    It looks like there might be a couple of different Avid 185mm IS adapters, maybe one will fit better than the other


  15. #15
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    Quote Originally Posted by cobba
    It looks like there might be a couple of different Avid 185mm IS adapters, maybe one will fit better than the other

    The fit is the same
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  16. #16
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    Hey -- This is really interesting. The one that shipped with my new 2009 is the top one in the photo (the beefier one). My old 2003 had the same type as the bottom one, but for a 160mm rotor, and the spacing on that one is slightly different (tried both calipers on it, and both work)

    So, are they still selling the second type? Can they be ordered? And are they just from previous years?

  17. #17
    rebmem rbtm
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    Quote Originally Posted by lostinNH
    Hey -- This is really interesting. The one that shipped with my new 2009 is the top one in the photo (the beefier one). My old 2003 had the same type as the bottom one, but for a 160mm rotor, and the spacing on that one is slightly different (tried both calipers on it, and both work)

    So, are they still selling the second type? Can they be ordered? And are they just from previous years?
    Here's the part numbers for them if you want to check.

    185mm Front Forged: 115.372102.900 (the older type)
    185mm Front Extruded: 00.5315.012.000 (the new beefier one)

  18. #18
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    Hey Guys,

    I just had my LBS face my disk mount tabs. Before we did it, we noticed that the mounting bracket itself, as well as the outside pad, were rubbing on the disk. We also noticed that the disk tabs were not square with each other (the lower one was 1mm closer to the wheel). We took off a fair amount and got both to fit with a little clearance. However, the mounting bracket (not the caliper anymore) still rubs the rotor quite a bit if I pedal standing up (I guess due to fork flexion).

    I guess I'm pretty surprised. Are other people having similar problems? I'm about to give up and see if they can order the old style forged mounting bracket for me, or just run it with a smaller 160 rotor and mount.

    thanks guys,
    adam

  19. #19
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    (btw, thanks for the parts #'s!)

  20. #20
    one less car
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    Quote Originally Posted by lostinNH


    http://www.flickr.com/photos/37967387@N02/3492358060/

    Can't seem to get it to host the image, but here's a link to the pic on flickr

    is that a spacer/washer between the bracket and the mounting tab? looks like one so removing, if it is, that should help
    nothing in life is real, so if anything goes wrong, blame the dead guy

  21. #21
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by lostinNH
    Hey Guys,

    I just had my LBS face my disk mount tabs. Before we did it, we noticed that the mounting bracket itself, as well as the outside pad, were rubbing on the disk. We also noticed that the disk tabs were not square with each other (the lower one was 1mm closer to the wheel). We took off a fair amount and got both to fit with a little clearance. However, the mounting bracket (not the caliper anymore) still rubs the rotor quite a bit if I pedal standing up (I guess due to fork flexion).

    I guess I'm pretty surprised. Are other people having similar problems? I'm about to give up and see if they can order the old style forged mounting bracket for me, or just run it with a smaller 160 rotor and mount.

    thanks guys,
    adam
    You said you had acces to a machine shop. Mill down the mount/adaptor. Removing ~1mm from the face against the fork tabs should fix it. I had to do this when I screwed up the tabs on a fork I made.
    mtbtires.com
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