Noisy brake rotor :(

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Noisy brake rotor :(
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flag SeanC1
Posted: May 29, 2022 at 17:11 Quote
I've got a new 203mm rt66 rotor and new icetek metallic pads in my 2-piston Shimano Deore M6000 brakes. I followed instructions to properly bed them in. They've lasted a few rides and worked well... but then today at the bike park after a few runs the rear started squealing loudly every time I touched the lever.

Why does this happen? It's so annoying and frustrating. Is it possible that the 2-piston brake is just not enough for downhill bike park riding? I'm 6' and 200 lbs and Riding a pivot Mach 6. Could it be heating up too much? Would the 4-piston Deore M6120 be that much better? Anything else I should try to remedy a squealing rotor??
flag patisfaction
O+
Posted: May 29, 2022 at 17:30 Quote
Try to cook them, happens to me all the time. I hold them over the oven element using long noses. I cook them for several minutes. Then I scrub lightly the pad surface and they look goldish and like new. They are then super quiet for a long time.

I know some people had success with 20 minutes IN the oven, or using a blow torch. I find on the oven element the easiest, simplest and quickest.
flag M0rd4c4i
Posted: Jun 15, 2022 at 10:46 Quote
It seems to be the thing with sintered pads, as soon as they get some contamination they start squealing.

Only thing you can do then is clean the pads and rotors when it happens, I've found motorcycle cleaner to work pretty well and for really deep cleaning isopropyl alcohol works very well.
flag eshew
Posted: Jun 15, 2022 at 11:27 Quote
I had a similar issue, clean and try pouring some water on them for the before the next few runs. Sometimes a little wet helps... but yeah, same issue, M8000 brakes with the RT66 rotors. After a few cleanings they quieted down.

I think the RT66's take a little longer to break in & shed a fair amount of debris while doing so. I think that process leads to the noise for a bit. But if it continues, torch the pads and try again.
flag thekragle
Posted: Jun 15, 2022 at 14:44 Quote
Lazy piston maybe, more likely on 4 piston, but may still be a possibility. Pull the pads and squeeze the lever a couple times and see if one piston comes out more than the other. Don’t extend them too far, and while out you can clean around the base of the pistons with some alcohol and a q-tip. Retract the pads with a plastic pry tool, and repeat.
flag SeanC1
Posted: Jun 28, 2022 at 23:04 Quote
So I used brake clean on the pads and rotors, used one of those kitchen blowtorches on the pads, plus sanded the pads down.

Back to the bike park and halfway through the day noisy squealing again. I am not riding the brakes either.

I have Deore 6000 caliper, 203mm rt66 rotors and the jo4c metallic pads with fins.
I thought i read somewhere that the pads with fins can be noisier?

Is it my equipment? Should I upgrade to the Deore 6120 4 piston caliper?

any other thoughts???

Thanks,
flag M0rd4c4i
Posted: Jun 29, 2022 at 5:02 Quote
@SeanC1, just ride.

It may be annoying as hell in some respects, but most importantly it doesn't affect performance.

One thing I know well that'll cause it is environmental contamination, and there's nothing you can do to prevent that. All you can do is clean the pads and rotors to manage it, but it'll always end up happening again.

So get some good Bluetooth headphones or a headset and get some good tracks on to drown it out.
flag hotrotors
Posted: Jul 4, 2022 at 12:23 Quote
Inspect the rotor(s) and see if scratches from the metallic pads are starting to develop. There's a chance the pads are "playing" the scratches on the rotor(s), like a needle playing on a record. This is common in the automotive world, and automotive pads have a backing material on them that dampens the frequency of vibration, so that the pads are quiet. There is also a "glue" that is placed on the back of automotive pads, and it glues them to the piston, again, for the same reason: dampening that frequency of oscillation.

If you find scratches, consider removing the rotor(s) and "dressing" it on a wire wheel, with the wire wheel being applied perpendicular to the scratches. You won't be "grinding off" any rotor material, you'll just be taking off the high spots on the scratches, so that the pads won't hang on them and sing. I've done it to really bad rotors, while waiting for new ones to arrive, and it's worked great. I had previously tried sanding them in a cross-hatch pattern with 60grit, and that did absolutely nothing, which was surprising.
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