Disc brake rub.

[Salty seadog]

Front rotor on the mtb seems to be rubbing. However it is only when i am on the bike, peddling or freewheeling. I cannot see any contact points when looking through the calipers, clear gap both sides of the rotor all way round. I have bent the rotor away from close contact points and even re centred the calipers. Nothing seems to cure it.

Any thoughts?

 

[lpretro1]

Warp in rotor

 

[Salty seadog]

Warp in rotor

I have bent it a bit to straighten it out, no rubbing when I'm not on the bike, just add soon as I get on it.

 

[Kajjal]

Check the wheel is in tightly, rotor bolts are properly done up and the disc brake caliper bolts are also properly done up. Sounds like something is loose and the stresses of riding make the brake rub due to this. Also check there is nothing stuck in the caliper like a small stone.

I once went mountain biking without doing the front wheel quite tight enough and it rubbed a lot.

The best way to centre the caliper is by eye. Look directly down the pads and set it so the distance to the disk is equal on either side. Then brake hard a few times and if it rubs check it again as you may need to make another slight adjustment. The undo caliper bolts, plug on brake, tighten caliper bolts approach is not very reliable.

 

[Salty seadog]

The best way to centre the caliper is by eye. Look directly down the pads and set it so the distance to the disk is equal on either side. Then brake hard a few times and if it rubs check it again as you may need to make another slight adjustment

When you say this do you still mean by loosening the mount bolts to make the adjustment?

 

[Tom B]

Are you double mcsure it's the brake. I spent months looking for a rub until another member suggested it might be a loose spoke... And it was.

That was a ching ching ching noise only present when I was on the bike.

That was after I'd bought a new rotor.

 

[Salty seadog]

Thats the noise.....

Just checked the spokes and none I would consider loose.

 

[Kajjal]

When you say this do you still mean by loosening the mount bolts to make the adjustment?

Yes that's right loosen the caliper mounting bolts and make the adjustment by eye. When tightening up the bolts again take it slowly as this can cause the caliper to move out of line a little if done too fast without holding onto the caliper properly.