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Post by kconner on Sept 7, 2011 9:01:17 GMT -5
I recently ventured into the world of disc brakes, and while I'm happy overall with them, I seem to be experiencing issues with the front rotor rubbing the calipers after transporting the bike with the front wheel removed.
First I downloaded the owners manual for my model of brakes and adjusted the calipers as per the manual. Didn't fix the problem.
After further research, I found that if you press the brake lever when the wheel is off of the bike, you may push the pistons out of place. After pushing the pistons back in with a tire lever or screwdriver, the rubbing sound goes away, but returns the next time I remove the wheel (and I'm pretty sure I'm not hitting the brake lever accidentally).
I'm going to a LBS in the morning to talk to them and look into getting a spacer, but I was just wondering if anybody might have any input. I almost wonder if this may have something to do with the brakes being brand new and maybe experiencing some sort of break-in period?
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Post by seenvic on Sept 7, 2011 9:10:00 GMT -5
Not an expert, but it sounds like they may need to be re-bleed.
The lever thing without the wheel in there is a big no no.
My kids will do this to my bikes if I leave them w/o the front wheel on and in a place they can reach the levers. They don't mean harm, it's just something kids do.
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Post by dgaddis1 on Sept 7, 2011 9:40:26 GMT -5
I wonder if the wheel is sitting crooked in the dropout or something when you put it back in the fork?
If you're touching the brake lever w/o a wheel in the fork, the pistons shouldn't be moving.
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Post by kconner on Sept 7, 2011 10:02:24 GMT -5
I wonder if the wheel is sitting crooked in the dropout or something when you put it back in the fork? If you're touching the brake lever w/o a wheel in the fork, the pistons shouldn't be moving. these brakes are lower end Tektro Novelas....mechanical, not hydraulic. after doing some more research online, it seems that there are quite a few people having problems with adjustments on these brakes....there might be a brake upgrade in the near future. i also wondered if the wheel was aligned correctly, and it appears to be from what i can tell. the rotor is trued as far as i can tell. it appears that i am at the adjusting limits after following the instructions for adjustment. not real sure what you mean by "the pistons shouldn't move without a wheel in the fork", shouldn't the pistons move when the lever is pulled regardless of whether the wheel/rotor is present or not? again, i'm new to disc brakes and am trying to learn as i go, but am out of ideas. after researching online, i almost wonder if it has more to do with it being a cheaper model brake than anything else after hearing about problems other people have had, especially with adjustment.
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Post by dgaddis1 on Sept 7, 2011 10:14:33 GMT -5
My bad, that should have read "If you're NOT touching the brake lever w/o a wheel in the fork, the pistons shouldn't be moving"
And yeah...never hear many good things about those brakes.
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Post by seenvic on Sept 7, 2011 11:04:55 GMT -5
The brake lever thing and rotors getting out of whack is for hydraulic only.
This is an upside of mech disc brakes.
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Post by bikerpanda on Sept 7, 2011 14:48:19 GMT -5
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Post by kconner on Sept 7, 2011 18:22:18 GMT -5
according to the LBS, slight rubbing is normal for a short period of time? and my calipers need to be re-centered on the rotor, even though the bike and brakes are brand new....
anyways, loosened the mounts and re-centered, which solved most of the rubbing. slight rubbing still persists, so I guess I'll give it a week or two to see if it improves.
bikerpanda, I'll definitely keep a lookout for the bb7s....they seem to be a popular model, and Christmas is in the not too distant future....
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Post by rsmith on Sept 8, 2011 12:45:22 GMT -5
My setup w/Shimano disc requires a couple very thin shims in the caliper mount. They slide between caliper and fork mount, shims straddle the mounting bolts. ("Y" shaped). If you have the proper clearance of pads, in rettracted position (ie: adequate space for rotor without drag), you can purchase shims at local hardware store to "center" the caliper (ensure wheel properly seated in fork), to gain equal space between pads and rotor, each side. Slight rubbing would not be Ok for me, pads don't wear that quickly, IMO.
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Post by kconner on Sept 8, 2011 14:17:35 GMT -5
My setup w/Shimano disc requires a couple very thin shims in the caliper mount. They slide between caliper and fork mount, shims straddle the mounting bolts. ("Y" shaped). If you have the proper clearance of pads, in rettracted position (ie: adequate space for rotor without drag), you can purchase shims at local hardware store to "center" the caliper (ensure wheel properly seated in fork), to gain equal space between pads and rotor, each side. Slight rubbing would not be Ok for me, pads don't wear that quickly, IMO. I honestly don't think these brakes are worth the trouble. I have them adjusted/centered so that they don't rub and they're silent, except for a phantom squeak every now and then that I need to track down. According to pretty much everything I've read here and on other sites, these brakes have a track record of needing adjustment almost constantly, so I've decided to go with the BB7s that everyone recommends. Just not sure when I'll get them.
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