Shudder/rumble from my Rear Brake

Ugh, that would be annoying.

This would drive me crazy too. I have a few oddball ideas.

I had a similar issue (low vibration through to handlebars) on an old bike and the culprit was a loose wheel bearing. Seems unlikely though since your bike is so new.

I would temporarily try a different wheel first, if you have a spare one, to see if the issue is with the wheel/hub/etc.

Next I would sand the pads a little, to make sure they’re not glazed.

A long shot, but have you tried a different pad type? (metal vs resin). If you had the same issue with a different type, you could probably rule out the pads anyway. If the issue goes away, you at least know there’s an issue with the old type.

An even longer shot, if it was a wheel vibration frequency issue, you could change the frequency by changing the overall wheel weight, such as adding a tube to a tubeless tire, or simply changing to a lighter or heavier tire.

Another long shot, if your brake was overheating for some reason, you might get this type of issue. This can be improved/solved by upgrading to icetech type components, if your bike doesn’t already have it.

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Try a new rotor, Kirk. I had this problem on my Chromag. It had fresh pads and bleed, but the rear brake shuddered. The rotor looked fine, but was in fact pretty badly glazed. The problem went away immediately. It would be a cheap thing to try and you can always use a spare rotor even of it doesn’t cure the issue.

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I just got a text saying my bike is fixed and ready to pick up. Couldn’t have been anything major or I would have got a call

I will let everyone know was was found and I appreciate everyone willing to offer an opinion.

If it is fixed I will celebrate by riding tonight, Saturday and Sunday

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Remove pads, depress pistons and lightly grease them (piston surface)

Loosen caliper to frame bolts

Replace pads/wheel

Get the wheel spinning and slowly tighten your caliper bolts while depressing the brake lever. This should realign your pistons to the rotor.

I do this once a week, and swap pads front to rear every few weeks.

Cheers

So what was wrong with it?

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They were able to recreate the noise (which was easy to do). Checked pads, rotors, caliper, wheel, derailleur etc. Tightened, adjusted and lubed and could not recreate the noise. Said it was fixed. Took it to the trail. Noise was gone. An hour into the ride it came back. Not as frequently but definitely still there. Because it came back after an hour perhaps the rotor/pads are heating up and causing the problem

Not sure what to do next.

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Are they SRAM brakes?

@bent6543 Shimano Deore XT

Replace the rotor.

If it’s not that, there’s a bearing contact point that’s vibrating. But the rotor is the cheapest, easiest thing to fix and a very likely culprit.

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Yeah, I’m telling ya, just borrow a wheel with the same size rotor and see if it disappears.

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Without seeing or checking adjustments I’d also be going to the rotor or pads could also be the issue. I find that metal ICE Tec pads are very easily contaminated and very hard to decontaminate. I run XT with metal ICE Tec pads on 2 bikes lost power on one brake and had some squealing issues. New pads solved that problem for me.

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Which pads solved the issue?

A new set of exact same pads.

Contaminated rotor? Could try scrubbing the rotor with rubbing alcohol to clean it, then rebreak it in.

It appears the trouble is in the rear triangle part of the frame. Not sure what exactly but Trek is sending a new one under warranty

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Winning!

Not yet

But close. Hopefully shipping isn’t delayed. Trek is a great company to deal with so hopefully this is the last of it for you.

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You are probably right @tossedsalad

I am curious about what exactly caused the problem