High pitch vibration from brakes

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knobster

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Hello,

Just picked up a 2020 Trek Rail 5 and noticed a strange noise from the brakes. Sounds like it's the rotors making a vibration sound. Seems to go away when I pull the front brake lever and I typically hear it riding down the road when coasting and especially in leaning in turns. It's not the typical brake pad squeal. I can make the same sound if I tap the rotor with something when the bike isn't moving.

Other than the sound, the bike seems to brake just fine. Any thoughts? Thank you in advance!
 
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If you can make the noise when tapping the rotor when not moving, check the rotor screws for proper torque as they could be loose.

My Rail has been in the shop for horrible rotor noise when pedaling, implying the torque from the motor is twisting the triangle pulling the rotor into the pads. It seems that the less than top notch brakes pistons are not retracting enough when released. It could also imply a cheaper wheel flexing when pedaling under motor torque. Seems slightly different than your situation.

Still waiting for the bike shop to conclude their investigation/parts replacement.
 
knobster said:
Hello,

Just picked up a 2020 Trek Rail 5 and noticed a strange noise from the brakes. Sounds like it's the rotors making a vibration sound. Seems to go away when I pull the front brake lever and I typically hear it riding down the road when coasting and especially in leaning in turns. It's not the typical brake pad squeal. I can make the same sound if I tap the rotor with something when the bike isn't moving.

Other than the sound, the bike seems to brake just fine. Any thoughts? Thank you in advance!
Click to expand...

Is it a newer Fox fork? Perhaps you need to adjust the axle clamp bolts.
 
Rail97Rider said:
If you can make the noise when tapping the rotor when not moving, check the rotor screws for proper torque as they could be loose.

My Rail has been in the shop for horrible rotor noise when pedaling, implying the torque from the motor is twisting the triangle pulling the rotor into the pads. It seems that the less than top notch brakes pistons are not retracting enough when released. It could also imply a cheaper wheel flexing when pedaling under motor torque. Seems slightly different than your situation.

Still waiting for the bike shop to conclude their investigation/parts replacement.
Click to expand...

Thanks for the reply. yeah that was the first thing I checked. Nice and tight. I'll check the clearance on the pads and see if it's potentially touching the rotors.
 
We had this on my other half’s Levo HT, it was described as a ringing noise. I thought it was a resonance caused by the knobs on the tyres as you could stop it by dragging the brake.

I tried everything and thought I would have to change the disc to get rid. I converted it to tubeless and it was gone never to reappear.

My advice would be to go up or down 10 psi in the tyre just to confirm And go from there.
 
Daffy said:
We had this on my other half’s Levo HT, it was described as a ringing noise. I thought it was a resonance caused by the knobs on the tyres as you could stop it by dragging the brake.

I tried everything and thought I would have to change the disc to get rid. I converted it to tubeless and it was gone never to reappear.

My advice would be to go up or down 10 psi in the tyre just to confirm And go from there.
Click to expand...

That's strange. I've solved things like that before and had no idea how. Just shrugged and walked away.. I'll take everything apart and put it back together and see. Who knows. Thanks for the reply
 
What brakes are they? on my rail 5 it came with Tektros and they made a hell of a noise, I swapped them for some code rs brakes and have never had a problem since.
 
Hornet said:
What brakes are they? on my rail 5 it came with Tektros and they made a hell of a noise, I swapped them for some code rs brakes and have never had a problem since.
Click to expand...

Yeah same Tektro brakes. I may look into that.
 
The rotors are low quality. I found they flexed and rubbed a lot. I replaced with RT76 rotors and the noise stopped and braking was more confident.

I purchased some shimano 4 pot brakes at the same time which are not yet fitted. I will put them on over the winter. ( I spent 4 weeks riding every day in the lake district doing around 1,000m of vertical a day and found the tektro brakes ok, not amazing, but good enough )
 
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