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  1. #1
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    New question here. Brake caliper hitting rim

    This seems to be either the rim or the caliper itself causing the issue. It is mainly on a hard turn were I get some flex. Any insight on how to fix this issue? It seems the metal "dot" on the inside of the brake caliper just hits the rim slighty and makes a small tinging sound.

    I am using BB7 with a standard brake mount, Stans Flow 29er Rim on a lefty DLR 80mm fork. I am also using a MK 29.2.4 up front tubeless maybe it is flexing hard and am I hearing the wrong thing make noise.



    pink
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  2. #2
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    Your caliper isn't anywhere near the rim without some very creative installation . Not sure what you mean by the metal "dot", though. The noise you hear is probably just the result of a bit of flex under load causing the rotor to contact the pads slightly, possibly your rotor is slightly out of true, too. Possibly your hub needs adjustment.
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  3. #3
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    What I mean by that is on the inside of the brake housing it is very close to my spokes and I hear the sound when I shift the bike side to side with force of course not just casually. I figured it was flex but from the sound it sounds like it his hitting spokes. On the inside of the BB7 there is a chrome piece on the housing that looks like a metal dot.

    If it is flex I am looking at my LBS then as they built the wheels and install the BB7s.

    pink
    Mr. Krabs: Is it true, Squidward? Is it hilarious?
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  4. #4
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    Could be a bit of inherent fork/hub flex, too. Are the rotors true? Any play in the front hub?

    If it's a ting ting or zing zing kind of sound, probably the rotor making contact with the pads (or the caliper if it's not setup right). Not sure what the caliper hitting the spokes would sound like, would think it would be pretty distinctive, though. Make sure the calipers are mounted/aligned properly, or have the shop do that if you don't want to try.

    My BB7 calipers (btw calipers is a better term than housing, the housing is the sheath the cable runs in) don't come very close to the spokes, but it's been a while since I've run a 160 up front, too. Is this with a 160 rotor? If so, you could go with a larger rotor so the caliper doesn't come so close to the spokes if you don't come up with anything else....
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  5. #5
    Did I catch a niner?
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    I use a 185 up front. I am going for a relatively flat ride today so I will see, if I do not like what I hear I will go back to my lbs on this one. Since they installed it I would hope they would align it.

    If I had to do this is it just as simple as take the caliper off and putting it back on, I do not know much about brakes.

    pink
    Mr. Krabs: Is it true, Squidward? Is it hilarious?
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  6. #6
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    You could try dialing the pads out a bit and see if the noise goes away. You could check your caliper install yourself by using the installation instructions at the sram.com site or even parktool.com (or the printed instructions that come with the brake); it's a tad more involved than just loosening and retightening the mounting bolts, though not by a lot.
    "...the people get the government they deserve..."
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  7. #7
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    It is most likely a symptom of having a big wheel mtb and a brake caliper designed for 26inch wheels. The spokes are hitting your Caliper. I have heard it. its alarming enough.

    The bigger rotor should help as it means moving the caliper further away from the the hub/up the fork. The spokes will be further inboard at that point.
    With any wheel, the spokes angle inward/inboard as they go away from the hub. More so on a 26inch than on a 29er wheel because the spokes have less distance to get from hub flange to centre of its rim.

    Also, the higher the hub flanges are, the more likely you will have problems. I recall a girlfriend of mine having issues with Avid juicy brake calipers hitting her spokes laced to tune hubs on a 26 inch wheel and a Reba fork! maybe a bigger rotor was the answer there too.
    Last edited by jja37; 08-18-2011 at 09:07 AM. Reason: spelling

  8. #8
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    Hi All,

    I have a related question (I think- I am a novice so please forgive). I am having a problem with my front hydralic disc brakes (QUAD QHD SD).

    It seems that the caliper (I think- the mechansim that pushes against the disc pad) goes up against the pad too much, causing noise when the tyre rotates and doesn't fall back into a stable position.

    What should I do? Do I have to bleed the brakes (I haven't done it once yet since I got the bike around 2 years ago); replace the disc pads or adjust something else amongst the screws I see there)?

    I did try making sure the pads are aligned (holding the brake after loosening the surrounding screws and centering the pads).

    Any help would be greatly appreciated.

    Thanks,
    Alex

  9. #9
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    bleed them
    "Nothing compares to the simple pleasure of a bike ride." - John F. Kennedy

    Setup:
    11' Giant XTC 2 29er

  10. #10
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    Thanks for the reply.

    Do you know if I can use Dot 4 brake fluid that is also used for cars?

    Thanks,
    Alex

  11. #11
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    bleed them? I thought BB7s mechanical brakes or am I losing it?

    I believe all of Avid's hydraulic brakes that are pre-bled are filled with Dot 5.1 but can use Dot 4 too.

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