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  1. #1
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    HELP ME - I'm going insane. Can't align rear disc

    OK, I've spent two weeks trying to get this right. Today I spent four hours on it.

    I can't get the rear disc to fit between the caliper. Right now there's a bit of rub.

    I have had four shims on each bolt that held the caliper in place.

    Currently I have two O-rings on the hub - no shims.

    I can't seem to get it - no matter what I try. I'm thinking that *perhaps* the disc is bent?

    I've taken a bunch of photos. Maybe somebody can give me some insight? Problem is I need to solve this by tomorrow as I'm packing the bike and going to Europe on Wednesday.

    It's a Magura Louise in the rear. Promax 160 rotor. Santa Cruz Blur frame.

    Photos: http://christhelinuxguy.com/gallery/...2_itemId=33068

  2. #2
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    bike shop time.

  3. #3
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    Turn around time here is at least 2 weeks

  4. #4
    TLL
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    It would appear from your pix that the caliper is not far enough inboard. Suggest you try more shims, perhaps a 5 mm shim plus a few 1mm shims. I have had up to 8mm on Louises in the past.

    What do you mean by "I have two 0-rings on the hubs"?
    Hadley rear hub service here and here.

  5. #5
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    Quote Originally Posted by TLL
    It would appear from your pix that the caliper is not far enough inboard. Suggest you try more shims, perhaps a 5 mm shim plus a few 1mm shims. I have had up to 8mm on Louises in the past.

    What do you mean by "I have two 0-rings on the hubs"?
    They are just shims that go around the hub about the size of the shims you use on the caliper. They are pushing the opposite way than if I put shims on the screws that connect to the caliper, though, of course. But somehow it works out. Do you understand what I mean?

    Do you know if I can buy these shims at a hardwood store? The LBS is getting pretty fed up. They told me they didn't have any more even though I told them I'd pay whatever.

    And I'm getting rather irate.

    I should have matched this bike with Martas but I figured I'd save 100 bux since most stopping power is from the front. SIGH.

  6. #6
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    Have you rebuilt the wheel? The distance from the end of the locknut on the axle to the caliper mount determines where the caliper sits in relation to the rotor. Shimano hubs often have spacers to set the exact distance. Perhaps the o-rings you mention are the same thing. If they are, adding more will move the rotor outwards which, from your description, should do the job.

    Tim

  7. #7
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    Is this a new frame? Or have you successfully set up a rear brake on it before?

    As mentioned above, from the pictures it looks like the caliper needs to move further inboard. Another possibility is the brake tabs need facing. An uneven coat of paint on the tabs could misalign the caliper.

  8. #8
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    Actually, yes. That's when all this began to happen. My LBS tightened the hub in the rear, then boxed my bike for a previous vacation I was suppose to go on, but I didn't take the box.

    I've tried two O-rings right now to no avail. There's an LBS which may sell them to me; any idea how many I should get? I rather use O-rings than 20 spacers.

  9. #9
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    Any spacer that will fit will be fine. Perhaps take an example to a specialty fastener/bolt supplier. The LBS may have left a washer off (they are much thicker than the spacers).

    Tim

  10. #10
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    Thanks. I FINALLY got it tonight. Perfect. Thank you.

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