[greene36]

So. I adjusted the brakes to stop them from squealing. After doing that, I noticed when I go fast, I get a sound that sounds like the rear rotor is ready to fall off. Going slow doesn't produce the vibration. The bolts are tight on the hub and it looks like the pads clear the rotor. The bike is a GT avalanch 3.0 Disk.. help..

 

[bikedreamer]

Is the rotor warped or bent? Wheel installed in the dropouts correctly? Brake caliper properly attached to the frame, and properly tightened?

What brand of brakes, btw?

 

[greene36]

the brakes are oem 'Tektro Novela' Is what is on the caliper. Rotor isnt warped, wheel is installed correctly, caliper is attached right, and torqued.

 

[granpa]

may be the wheel or cassette?

 

[greene36]

no. its the brakes. I tighten the line and it squeels. I loosen the line and it audibly vibrates. I feel that there shoud be a sweet spot, but can't seem to find it.

 

[4slomo]

Check if your caliper is out of alignment (twisted) relative to your brake disc.

 

[greene36]

The adapter was never removed off the caliper. but the adapter was removed from the frame.

 

[BurnNotice]

Sometimes the calipers which attach to the frame will work loose and shift and most often create a rasping or metal rubbing sound. This could be the issue especially if you know the rotors are secured tightly and the rotors are not warped. I usually eyeball my pads in relation to the rotors as I spin the tire to see if it is a warp or shifted caliper.

If this is the culprit make sure you use loctite on the screws when tighten them down once you get the caliper aligned properly.

 

[scottzg]

i would either ignore it or buy some quality brakes, like bb7's or some hydros that retail for over 100$ per brake. Those thing suck.

 

[greene36]

i would either ignore it or buy some quality brakes, like bb7's or some hydros that retail for over 100$ per brake. Those thing suck.

For now they do the job. When the pads go, and I assume they will go quick, I will end up buying the bb7's.

 

[BurnNotice]

The fact is if you have isolated the noise to brakes it is a mechanical issue of two parts coming in contact with one another. Not really a issue with quality. When you ride alot and log miles you have to constatntly adjust components that may loosen a bit. If you ride the rough terrain I do then you do it almost after every ride. Or at least you do a visual check of the bike's key components.

I cheap set of brakes are as good as a $300 per front or back just minus all the glitter. I mean brakes are what they are. I bet you have a a simple fix there. Just need to know how to go about finding it.

 

[yogidave]

Pads

Is it time to replace the pads? Sometimes brakes will make noise when pads are too worn down, which might allow stuff to rub or operate outside of the "quite" range of position, etc...

Is there any oil, etc on the rotors? spraying chain lube at the chain will get some on the rotors leaving residue... use rubbing alcohol to clean the rotors with a clean paper towel and see if it gets better.. can't hurt.

check caliper position.. if crooked, squealing might happen... but it's best to replace pads AND realign the caliper(s).

Good luck.

 

[scottzg]

I cheap set of brakes are as good as a $300 per front or back just minus all the glitter. I mean brakes are what they are.

clearly you haven't had to deal with these brakes. They're pretty incredible how difficult they are to set up properly. They're the sloppiest built bike part i think ive ever seen.

 

[BurnNotice]

clearly you haven't had to deal with these brakes. They're pretty incredible how difficult they are to set up properly. They're the sloppiest built bike part i think ive ever seen.

I used $75 disc brake systems and one to the next brand are pretty elementary. But without seeing these particular one's you are right. I sometimes get the feeling people believe the more you spend the more you get. Not always true.

 

[eltazar]

Check if by some freak chance you don't have loose spokes - they can vibrate and howl when braking.

 

[greene36]

Check if by some freak chance you don't have loose spokes - they can vibrate and howl when braking.

Problem goes away when braking. So spokes are fine.

 

[zebrahum]

Your pads are hitting the rotor. Probably because the caliper isn't adjusted properly and "twisted" as another person mentioned. Here's what you do:

1) Take the fixed pad adjuster and open the inner pad up as far as it will go
2) Take the cable off of the fixing bolt so that both pads are retracted as far as they will go
3) Make sure your wheel is straight in the dropouts and properly secured (tight enough)
4) Loosen the bolts that hold the caliper to the adapter and visually line up the rotor in the center of the caliper gap
5) Move the fixed pad adjuster back in until it only just barely does not make sound when the wheel spins (sometimes it's necessary to have a small amount of rub, but this is a good starting point)
6) Pull the cable back onto the fixing bolt and adjust the lever pull. I usually leave about two turns from tight on the barrel adjuster at the lever to allow for small adjustments.
7) Take the lever and while watching the rotor very carefully, make sure the rotor does not flex like it is being twisted. If it does, adjust the caliper, verify the pad alignment again, and try again. If the rotor twists, it will probably rub and will rob huge amounts of power from your brake.

Remember, the less you bend the rotor, the better the power will be. For reference here is a description of how Tektro recommends to do this procedure:

http://www.tektro.com/04support/pdf/Novela-English.pdf

Pretty similar to what I said, just watch for twist and bending of the rotor. If you're getting noise, the rotor may be warped or your pads may be too far in. Check both.

Good luck!

 

[greene36]

Your pads are hitting the rotor. Probably because the caliper isn't adjusted properly and "twisted" as another person mentioned. Here's what you do:

1) Take the fixed pad adjuster and open the inner pad up as far as it will go
2) Take the cable off of the fixing bolt so that both pads are retracted as far as they will go
3) Make sure your wheel is straight in the dropouts and properly secured (tight enough)
4) Loosen the bolts that hold the caliper to the adapter and visually line up the rotor in the center of the caliper gap
5) Move the fixed pad adjuster back in until it only just barely does not make sound when the wheel spins (sometimes it's necessary to have a small amount of rub, but this is a good starting point)
6) Pull the cable back onto the fixing bolt and adjust the lever pull. I usually leave about two turns from tight on the barrel adjuster at the lever to allow for small adjustments.
7) Take the lever and while watching the rotor very carefully, make sure the rotor does not flex like it is being twisted. If it does, adjust the caliper, verify the pad alignment again, and try again. If the rotor twists, it will probably rub and will rob huge amounts of power from your brake.

Remember, the less you bend the rotor, the better the power will be. For reference here is a description of how Tektro recommends to do this procedure:

http://www.tektro.com/04support/pdf/Novela-English.pdf

Pretty similar to what I said, just watch for twist and bending of the rotor. If you're getting noise, the rotor may be warped or your pads may be too far in. Check both.

Good luck!

Thanks Zebrahum, I did not know those adjustments on the adapter could be made, I thought it was all just a fixed plate. Guess I should have read the manual that others have provided.