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Thread: Bent brake tab

  1. #1
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    Bent brake tab

    Hi all,

    Last sunday, I went for a ride on my Chili. The ride ended up being quite short, because on the first descent, I lost traction and fell. Nothing too extraordinary there I was pretty much uninjury, except for a nice bruise on a leg.

    However, the bike took a bad hit. I noticed that my rear brake was sort of seizing the wheel. I fact, I have the impression that the rear mounting tab for the brakes is bent inwards, causing the brake adapter to touch the rotor. I am quite upset that I could damage the frame in such a way, from a seemingly pretty small crash.

    Bent brake tab-zoomed_small.jpg

    Now the question is: How do I fix this?
    1/ I could take a pair of pliers and try to straighten the tab. My fear is that I could break the tab entirely. This would be quite bad
    2/ I could ignore fixing the tab and simply play with the number of washers in an attempt to make the brake adaptor be parallel to the rotor.

    Feedback appreciated.
    Thanks.

  2. #2
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    Bummer of a fall, sometimes things just hit right at that point they shouldn't. Kevin/Noel might have some feedback, but to keep up & running for now I'd just try to play with the washers and not risk further compromising the structure of the tab.

  3. #3
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    Makes me glad my Delirium brake mount is built into the dropout.

  4. #4
    TSC
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    With brake tolerances being as tight as they are I don't think can fix it with washers. It's most likely bent so if you get part of the pad free from binding another part of it will be bound. I think you will end up straightening it yourself; but I would ask Knolly first (as CZ suggested). Two suggestions:

    1) Don't use pliers. Use a crescent wrench--preferably one that doesn't have lots of slop (i.e. closely-spaced threads).

    2) A little bend goes a long way! You probably bent the tab a mm or less (much more than that and your back wheel would not move without unloosening the bolts on your adapter mount). Don't over-bend your tab because you will have to bend it back. Bending it back and forth will fatigue the metal.

    Here's a thread that seems to have some good advice: Bent chainstay brake tabs

    Good luck!
    "sounds like you need to find a better mechanic..." -- Calhoun

  5. #5
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    Actually, I wonder if you can face it to get it right? Trying to remember if the brake facing tool that Jude @ Magura USA used on my bike was dropout-seated or not....

  6. #6
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    is it definatly the tab thats bent and not the rotor. drop noel an email. he will help you.

  7. #7
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    Looking at that pic leaves me with a couple questions...

    1. Did you mean the caliper is touching the rotor and not the adapter? In the photo it looks like the caliper where the rotor passes through might be rubbing and it also looks like the inside edge of the caliper where it mounts is set slightly inside the adapter. Can you not just loosen the bolts on the caliper, recenter the brake, and re-tighten?

    2. Maybe I'm the only one but I've never run any washers between the tabs on my frame and the adapter, if I did my brakes would rub all the time. Done it this way with Hayes, Magura, and Shimano on a couple different frames and the caliper always centers up just fine.

    3. If a bike fell the right way, even on a slow speed crash, I could certainly see the tabs bending a bit if the impact was focused on them. Agree that a facing tool might be better than trying to re-bend because aluminum doesn't typically do well with bending back and forth.
    Sipping the Knolly Whisquillappa

  8. #8
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    I run magura's as well and I'd suggest as catch22 has to get rid of the washers between tabs and adapter. it also could be that the caliper just moved on the adapter from the impact without bending anything. good luck

  9. #9
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    Quote Originally Posted by CharacterZero View Post
    Actually, I wonder if you can face it to get it right? Trying to remember if the brake facing tool that Jude @ Magura USA used on my bike was dropout-seated or not....
    As others have said ask Knolly first, but facing the disc brake tabs is a good option. I bent my disc brake tabs on my old Kona stinky deluxe when my bike landed on a big rock. My LBS faced the disc brake tabs and it lined up perfectly again with no issues. This happened 6 years ago and the bike was a 2001 model. I have since given it to a friend and it's still going strong!

  10. #10
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    Thank you all for the helpful feedback. The caliper mounting foot does rub against the rotor, as illustrated in this picture (the anodizing is gone).

    Bent brake tab-p9120131_small.jpg

    I will need to have a closer look when I have more time. Removing washers (I got the bike with them this way) or adjusting the brake mount screws seem like a viable solution. The link posted above also looks very informative and will come in handy if I decide to unbend the tab.

  11. #11
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    Update: I had a closer look at the brake tabs. I think this picture I just took illustrates the bent best.

    Bent brake tab-p9160139_zoomed_small.jpg

    The brake rotor is also bent, but I'm not too worried about this. I might be able to straighten it with a crescent wrench and I am planning on upgrading to 180mm anyway.

    Here is another topic about bent brake tabs: Bent brake tabs on seat-stay - Options?

    Also, there seem to be dedicated tools to face the brake tabs, from Park Tools (DT-1.2), Hope, Magura, CTS and probably others.

  12. #12
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    Quote Originally Posted by F-Bomb View Post
    Update: I had a closer look at the brake tabs. I think this picture I just took illustrates the bent best.

    Click image for larger version. 

Name:	P9160139_zoomed_small.JPG 
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    The brake rotor is also bent, but I'm not too worried about this. I might be able to straighten it with a crescent wrench and I am planning on upgrading to 180mm anyway.

    Here is another topic about bent brake tabs: Bent brake tabs on seat-stay - Options?

    Also, there seem to be dedicated tools to face the brake tabs, from Park Tools (DT-1.2), Hope, Magura, CTS and probably others.
    I would be curious to see this photo with the washers removed. It almost looks like the bolt is crooked in the tab. The bolt should sit perfectly perpendicular to the brake tab. Maybe it's just my eyes, but it looks like that angle is less than 90 degrees.

  13. #13
    TSC
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    Quote Originally Posted by Berkley View Post
    I would be curious to see this photo with the washers removed. It almost looks like the bolt is crooked in the tab. The bolt should sit perfectly perpendicular to the brake tab. Maybe it's just my eyes, but it looks like that angle is less than 90 degrees.
    Trust F-Bomb; it's bent.

    Name:  Bent Brake Hanger.jpg
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    "sounds like you need to find a better mechanic..." -- Calhoun

  14. #14
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    Time for an update... I have returned from a ride, which means that the bike is fixed

    I have employed the crescent wrench method. Despite my misfortune, I have to say that the tabs are actually quite sturdy. A little crescent wrench won't do. Better use a rather large one, like the bottom wrench in this picture.

    Bent brake tab-p9180138_small.jpg

    I put some tape on the tabs to avoid cosmetic damages, then used the wrench to bend the taps back to a vertical position. It takes a bit of force, even with a large wrench. I took my time and bent back by little increments and checked the result often. Looks better doesn't it?

    Bent brake tab-p9190140_small.jpg
    (could need some nice red squares )

    See this wheel spin!

    Bent brake tab-p9190141_zoomed_small.jpg

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