I have a frustrating issue with my MTB and want to ask how I can go about actually diagnosing this issue.
I have a MTB Shimano Disk brakes. These are mechanical and one pad is pushed into the rotor and then onto the inner pad.
I had found that the braking on the bike had become weak, at best. So I bought some new brake pads by EBC and replaced them.
The thing is, the braking is still very weak. Basically, I am tightening the brake and walking the bike on the ground I am still able to rotate the wheel, showing that the pads are simply not gripping the rotor tight enough.
- I have tightened the brake cable (at both ends), which doesn't seem to do much.
- I have tried to realign the brake housing mechanism (by unscrewing the top and bottom allen screws) and tightening the brake and then retightening the screws.
- The wheel rotor does not state any requirements for brake materials.
But I'm lost... I think I need to tighten up the pressure piece that the brake actuates. But I can't find any advice about this (here and youtube). I did find an allen screw that looked like it worked on the pressure mechanism but results were inconclusive.
I am suspecting that I could maybe try and put something on the caliper to stop the spring/brake mechanism travelling on the caliper, which it does a little.
I am also aware that disk brakes do need to be used hard for 40+ times to wear in, but the thing is this appears to be the same issue (or symptom, at least) that was on the older pads which have been used extensively.
Extensive testing and "bedding in" of the new brake pad, and reading the answer by Swifty, raises some flags for me: that the issue is completely that the pads themselves do not exert enough pressure on the rotor to stop its rotation.
- The pads do seem to significantly bend and flex the rotor.
- The pads possibly do not yet have enough friction/grip from bedding in but as stated, this issue seems to be that the pads are somehow bending the rotor which causes a delay in the braking mechanics.
The cable tension is absolutely fine. The pads at rest are very close but not touching the rotor.
The issue is that as the braking system only moves the outer pad, this is pressing the rotor and then pressing the rotor towards the inner pad, with visible movement (several mm).
After comments with Chris H, I have had a nose around at the mechanism and found a screw for tightening the fixed pad nearest the wheel. This looks promising. It feels like there's more grip and riding this morning (day 2) with this is better, not perfect but definitely better.
BELOW: Loose view. Brake is not triggered:
BELOW: Tight view with brake triggered: