front rotor won't stop rubbing
06-13-19, 10:57 PM
#1
commu*ist spy
Thread Starter
front rotor won't stop rubbing
I have problem with front rotor rubbing on my 2016 giant tcx, which has 160 rotors. I've tried everything. truing the rotor, getting new rotors, different pads, different wheels. yet for whatever reason, my front rotor still rubs, when i stand up to climb/sprint, and especially when I brake very hard during a descent, which I understand causes some warping.
I thought i'd solve the problem by going to shimano ice tech floating rotors (RT-86), which are supposed to cool a lot faster. it actually became worse. if I do any moderate braking on the RT-86 rotors, they would rub on the pads for a while, until they cool off. the other day, I came off a steep descent and braked to slow down, and for about 10-15 seconds, my front rotor was rubbing so loud without braking that it was making squealing noises. the noise then subsided, but this is absurd. I want the noise to go away
one theory I have is maybe there's moisture in the rotors, such that under heavy braking, water evaporates, and prevents the pads from retracting all the away. Perhaps a bleed job is in order, although the bike is basically new old stock and barely has 1k miles. Also, this does not explain why the problem is worse with the ice tech rotors. And it doesn't explain why even from my front door, if I start sprinting or climbing out of the saddle, the rotor rubs without any braking.
any ideas?
I thought i'd solve the problem by going to shimano ice tech floating rotors (RT-86), which are supposed to cool a lot faster. it actually became worse. if I do any moderate braking on the RT-86 rotors, they would rub on the pads for a while, until they cool off. the other day, I came off a steep descent and braked to slow down, and for about 10-15 seconds, my front rotor was rubbing so loud without braking that it was making squealing noises. the noise then subsided, but this is absurd. I want the noise to go away
one theory I have is maybe there's moisture in the rotors, such that under heavy braking, water evaporates, and prevents the pads from retracting all the away. Perhaps a bleed job is in order, although the bike is basically new old stock and barely has 1k miles. Also, this does not explain why the problem is worse with the ice tech rotors. And it doesn't explain why even from my front door, if I start sprinting or climbing out of the saddle, the rotor rubs without any braking.
any ideas?
06-14-19, 12:07 AM
#2
Senior Member
When you say you tried everything, I assume that means aligning the calipers too.
Google it if you haven't. Lots of folks have the same problem. That is one reason I avoid disc brakes for the lower priced bikes I buy.
But since you have them, If you still can't stop or reduce, You might get a LBS to have a look, It shouldn't be that loud. Some rubbing isn't uncommon.
Google it if you haven't. Lots of folks have the same problem. That is one reason I avoid disc brakes for the lower priced bikes I buy.
But since you have them, If you still can't stop or reduce, You might get a LBS to have a look, It shouldn't be that loud. Some rubbing isn't uncommon.
Last edited by xroadcharlie; 06-14-19 at 12:14 AM.
06-14-19, 01:48 AM
#4
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Take heart - it can be fixed by a good bike mechanic. There are lots of us riding with disc brakes with no rub, no noise and no problem. Let us know what the bike tech says.
06-14-19, 10:19 AM
#5
Full Member
Sounds like the caliper pistons aren't retracting. Try pulling the wheel off and pushing the pistons flush with the caliper and then test. You may have a bit more travel in the levers after doing this, so test in a low-traffic and flat area. Depending on the type of levers you can adjust freestroke and lever reach to accommodate.
