[provin1327]

I'm trying to find out why my rotor is intermittently rubbing my brake pads. I'm running a set of Hayes Dominion A4 brakes on a Guerrilla Gravity Gnarvana. I've centered the caliper and in the repair stand the rotor and brakes make zero noise. When I take it off the stand and pedal it around it will start to make noise. The rubbing seems to come and go on its own, it's not a constant rubbing on a single part of the rotor like an out of true rotor. Using the brakes doesn't seem to make the rubbing stop or change once it has started. I really only seem to hear the rubbing when I am pedaling uphill or when I hit a small bump when seated pedaling uphill. That symptom makes me think the the seat stay or chain stay is somehow shifting side to side which is causing the caliper and caliper mountain bracket as a whole to move and rub on the rotor. All my suspension bolts are torqued to spec. My only other thought is that the hub is somehow moving or twisting? I'm not sure if that's even possible.

Has anyone ever dealt with something like this before?

 

[EricTV]

I'm trying to find out why my rotor is intermittently rubbing my brake pads. I'm running a set of Hayes Dominion A4 brakes on a Guerrilla Gravity Gnarvana. I've centered the caliper and in the repair stand the rotor and brakes make zero noise. When I take it off the stand and pedal it around it will start to make noise. The rubbing seems to come and go on its own, it's not a constant rubbing on a single part of the rotor like an out of true rotor. Using the brakes doesn't seem to make the rubbing stop or change once it has started. I really only seem to hear the rubbing when I am pedaling uphill or when I hit a small bump when seated pedaling uphill. That symptom makes me think the the seat stay or chain stay is somehow shifting side to side which is causing the caliper and caliper mountain bracket as a whole to move and rub on the rotor. All my suspension bolts are torqued to spec. My only other thought is that the hub is somehow moving or twisting? I'm not sure if that's even possible.

Has anyone ever dealt with something like this before?

I have had a very similar problem and it turned out I needed to clean the brake pistons. Once I cleaned them the pistons stopped getting stuck and the intermittent rub went away. There are several videos on youtube that show how to do this. You will need brake fluid and q-tips.

 

[bingemtbr]

Yes. My solutions are split between either a loose part (caliper/disc not fastened to spec) or heat from braking causing the rotors to warp.

Loose parts are easy enough to diagnose. Just give everything--even the obvious stuff like thru axles/skewers, brake pads, etc--a once over. For rotors, I use 2-part IceTech rotors and on my primary trail bike, I run 203mm rotors.

 

[provin1327]

I have had a very similar problem and it turned out I needed to clean the brake pistons. Once I cleaned them the pistons stopped getting stuck and the intermittent rub went away. There are several videos on youtube that show how to do this. You will need brake fluid and q-tips.

Thanks, I think this may have been the issue. I just cleaned and lubed them and after a quick parking lot test the intermittent rubbing seems to be gone.

 

[ucdengboss]

I notice this on my front brakes, Shimano XTs, after heavy braking on a downhill. Normal riding I don't see any issues normally.