brake rub

Del34

My rear mechanical disc is rubbing when I adjust the pads outward the rub stops but they lose grip on the rotor and there's less stopping power any suggestions

pesky_jones

Perhaps the rotor is bent?

The Rookie

Sounds like the calliper is out of alignment....

Cqc

To centre the calliper: Loosen calliper bolts, pump brake, hold it as you tighten them up. If that doesn't do it, check out the rotor straightness, and sandpaper pads to remove dirt which may be rubbing

gt-arrowhead

The Rookie sounds correct to me.

Do what Cqc said, but it does still rub sometimes even when you do that, because mechanicals only have 1 pad that moves. The one one the inside is stationary so can still rub when using the method Cqc said. If its that bad even after doing that method just do it, then make tiny adjustments. Shining a torch through the caliper from the opposite side of the caliper helps you see how much of a gap there is. The idea is to get the stationary pad as close as possible so your rotor doesnt bend when you brake.

The caliper can move when tightening the caliper bolts down. You may not have noticed. Turn each bolt bit by bit to stop this.

If the pads are brand new just give it a chance to bed in. The rubbing stops after a bit of use.

This is a good thread to read. I had similar problems and a few people posted some really good replies that you can make use of. viewtopic.php?t=12936144&p=18483016

Hope this helps.

Kowalski675

Cqc wrote:

To centre the calliper: Loosen calliper bolts, pump brake, hold it as you tighten them up. If that doesn't do it,

It won't - he said he has mechanical brakes, not hydraulics.

gt-arrowhead

It wont centre the caliper as such. Just pull the stationary pad to the rotor.

Kowalski675

GT-Arrowhead wrote:

It wont centre the caliper as such. Just pull the stationary pad to the rotor.

It won't do anything of any use (just leave him with a permanently rubbing pad on one side). He needs to straighten the disc (if necessary) adjust the pad clearance with the adjuster, centre the caliper visually (or with a feeler gauge), then tighten the caliper mounting screws. Or put the crappy things in the bin and buy some hydraulics

gt-arrowhead

Thats why youve got the bit on the wheel side of the caliper that lets you adjust the pad distance.

After you pull the lever the stationary pad should be right up against the rotor, and if it rubs (most likely will) then you bring the pad back a bit using the adjustment. Just turn it anticlockwise.

The mechanical caliper i had was awful, but i reckon part of it was down to the fact that i had trouble setting it up correctly. I think V brakes are alot better than mechanicals. Well, the mechanical disc brake experience ive had anyway. They were weak and very noisy. And the lever felt awful.

Kowalski675

I know how to adjust mechanical disc brakes, lol - the crappy things on my Kraken needed doing after every ride. Terrible invention.

The Rookie

Yes but if the calliper is at an angle, no amount of adjusting will get it to work right, so it needs centring and then adjusting.

To centre a mechanical calliper, wind the adjusters in until the brake is locked solid, then do up the retaining bolts, then adjust.

Some callipers are dual adjust, some are single where the only way to adjust the static side is by re-centring the calliper (stand up Grimeca, it was a shite design!)