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Old 05-24-11, 03:30 PM   #1
corkscrew
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BB7 install with 185mm rotors - one side I can't adjust properly...

So I ordered 185mm rotor & BB7 kits from Jensens for my Recumbent trike.

I installed them using both front brackets, just like the bb5's and 160's I removed.

Now, here is the problem, I have one adjusted and it spins freely without singing.

The other, sings even with one side backed out - the outside side has plenty of room. Do I need to bend the mounting bracket? Everything is snugged down pretty tight...
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Old 05-24-11, 03:38 PM   #2
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I'm not "seeing" what you mean 100%, but couldn't it be the calliper which needs adjusting, if you can't get the rotor through there without it making any noise? I assume that you've backed off the pads on both sides.

In any case, unless you've banged up the mounting bracket in the past, which could possibly account for it needing bending now, don't try adjusting your brakes by bending anything.
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Old 05-24-11, 03:45 PM   #3
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Correct, with both pads backed all the way into the caliper, the rotor still provides a bit of braking and noise.

As far as I know, it's never been banged, and I don't like last ditch "Hit this with a hammer" solutions. Just can't figure out why one will install and work while the other rubs even with the pads all the way out.
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Old 05-24-11, 05:51 PM   #4
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look for where it is rubbing
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Old 05-24-11, 08:23 PM   #5
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Warped rotor.
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Old 05-25-11, 09:27 AM   #6
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Don't think it's a warped rotor - as it makes contact during most of the rotation.

I'm starting to think it is the mount. Looking at it straight on it looks like it's been bent inward a bit. Esp compared to the mount on the other side of the trike.

Haven't taken any corrective measures yet, but will take a closer look tonight.
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Old 05-25-11, 09:51 AM   #7
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Quote:
Originally Posted by corkscrew View Post
I'm starting to think it is the mount. Looking at it straight on it looks like it's been bent inward a bit. Esp compared to the mount on the other side of the trike.
Even if the mount was slightly bent inwards the BB7 should be mounted with the CPS/Tri Align washers that allow the caliper position to be mounted on a tilt if needed.


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Originally Posted by corkscrew View Post
Don't think it's a warped rotor - as it makes contact during most of the rotation.
If the rub is coming from the inside pad and if the caliper can't be positioned inwards any more, the rotor can be shimmed outwards on the hub to stop rubbing.

Last edited by cobba; 05-25-11 at 10:12 AM.
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Old 05-25-11, 09:54 AM   #8
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You might consider shimmying the mounts with shaved rubber washers.
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Old 05-25-11, 09:56 AM   #9
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Good start over step:, loosen the "postmount" bolts that hold on the caliper
to the adapter,
grip the brake lever, to have the caliper grip the disc,
then re-tighten those bolts.

thats going to align the caliper to the disc. ..
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Old 05-25-11, 10:15 AM   #10
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Because it's a trike do you have to use the mounting bracket on the "wrong" face of the adapter on one side? If so it's possible that the caliper mounting holes are not centered in the thickness so you are not able to get the one caliper to adjust inwards enough for the inside fixed pad to be clear of the rotor.

Or it could be a number of other issues. I'd start by measuring the rotor face to ISO bracket on the frame on each side. If both are the same spacing then it's the new caliper size adapter bracket is not symetrical and you'll need to either make it "thinner" or to slightly elongate the side to side adjustment slots in the caliper body to allow for the extra half millimeter it sounds like you require. If the ISO mount points on your frame are not equidistant from the rotors then you'll need to figure out why. Is it the frame that is tweaked or is the offset on one wheel different from the other or is it something else? That part is up to you to determine.
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Old 05-25-11, 08:46 PM   #11
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the first time i set up a new frame with disc brakes i spent most of an afternoon screwing around with the brakes. i was having problems exactly like what you're describing. the calipers were rubbing pretty badly most of the time.

since i had a good shop within walking distance and some errands to run i brought it down there. The mechanic got it all fixed for me - he said the disc tab wasn't aligned, it was off a little and that was causing the problem. he prepped it, did a small amount of filing and the brake's been good since.

so much for QC
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