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My bike was squeaking from the front wheel area when I tilted it to one side or another, but not when I rolled forward or used the brakes.

I figured it was probably my disc brakes so I took them out to clean them and one looks really worn down. See pics. Specifically the bottom one which looks really worn at the bottom right. Should I worry?

enter image description hereenter image description here

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    Looking at them on-edge to see the pad thickness would be more useful. Regardless, brake pad are relatively cheap, so I'm pretty quick to replace them, especially on my mountain bike where certain rides can take them from 75% worn to 98% worn pretty quickly. – Paul H Apr 8 at 17:48
  • I just added another photo. Is this the angle you were looking for? – Daniel Weiss Apr 8 at 17:59
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    Would switching the sides be a good idea (kind of like rotating tires in a car) – Daniel Weiss Apr 8 at 18:22
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    I don't see how that would solve any problems – Paul H Apr 8 at 19:37
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    If they squeak when you lean the bike, but not while braking, then there's something on your bike that needs to be tightened up. Is your thru-axle or quick-release done up tightly enough? If you try to move the caliper on the fork does it feel firmly bolted on? From the uneven wear on the pads, I recommend straightening your brake caliper up. – Carbon side up Apr 8 at 20:51
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Park Tool recommend the brake pads be at least 1mm thick. SRAM and Shimano have slightly different recommendation I think so look up the specs on your particular model of brakes.

I'd definitely be concerned by the asymmetrical wear. The squeaking when the bike is canted over is also indicative of an issue. I'd start by checking the front wheel hub for any play in the hub bearings. Make sure the wheel is installed correctly, then hold it off the ground, grab the tire/rib and push and pull side-side. You shouldn't be able to feel any movement between the wheel and fork.

  • In my experience uneven brake pad wear often relates to caliper being out of alignment with the rotor. – Rider_X Apr 22 at 19:37
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I would do two things here. Firstly, check the movement of the pistons. If only one is moving, it may need a little help. You can use a firm plastic or large flat head screwdriver to press on the affected piston to try and align it. Push the moving one back in as far as it will go.

Once you get some movement out of it, it’s worth getting some lubrications over the piston to help the rubber o-ring keep a seal and slide within the calliper body. I’m assuming hydraulic brakes here.

Make sure pads and discs are well away from any lubricant as you do this. You probably don’t want a solvent-based lube here either. If your brakes use mineral oil like Shimano use, that oil is perfectly fine to use. I’ve used chain line in the past. Let it soak over the piston and give it a good clean with a rag afterwards.

Once things are moving again, you should re-centre you calliper against the disc. With the pistons pushed back and pads and wheel re-fitted, loosen the bolts holding the calliper to the frame. Squeeze the brakes until they feel like normal braking and check that the disc is close to central in the calliper. If it is, Whilst holding the brake lever on, nip the bolts up enough to keep the calliper in place and then tighten to the correct torque once you’ve released the brake.

You shouldn’t hear the brake rubbing on the pads as you spin the wheel. If you get an intermittent rub, your rotor may be slightly bent but that’s the subject of another thread.

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