Rear brake dragging?

When I'm out riding and I stop for gas, I can't help but notice how my rear brake rotor feels much hotter than my fronts even though I use the fronts 100x more. Although there's nothing perceptible at the moment in terms of noise or damage, I'm wondering if the rear is dragging just enough against the pads to generate heat.

This heat could explain why my rear brake res is pitch black. There are a lot of factors at play here, so I thought I'd just ask after having no luck with search. On every other bike I've ever owned the rear rotor is always cold in comparison to the fronts when I stop for gas. The bike is due for tires in 600mi so I guess that's one more thing to get checked out.

Are you seeing any abnormal wear? Put it on a stand and pump the brake and see what your getting. How bad does the fluid look. Changing the rear fluid only takes a few minutes. I'd also clean around the caliper. I doubt it's anything serious.

SOULRIDER said:

Are you seeing any abnormal wear? Put it on a stand and pump the brake and see what your getting. How bad does the fluid look. Changing the rear fluid only takes a few minutes. I'd also clean around the caliper. I doubt it's anything serious.

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Not sure about abnormal rear. When I had tires replaced at 2250mi I had 80% left on the rear brake pads. At face value that sounds like a lot of rear brake pad wear to me, but I have nothing to compare it to. The tech didn't say anything about it being abnormal when he gave me the numbers. I cleaned the rotor (which looks fine) and only the expected amt of brake dust came off.

The fluid in the res is pitch black - I'll change that and see how it goes. Suspect you're right about it being nothing - after all if it were a catastrophic failure in waiting I'd already be on my ass from it.

For what it's worth, my rear fluid reservoir is also jet black - but I never made any direct observations of the rear rotor being hot.

Probably related, but my rear brake is now spongy - almost as if there's air in the line, but I haven't leaked anything out. It doesn't actuate anymore at all, e.g. it won't stay put if I use the rear brake in neutral on an incline. My schedule should open up a bit and I can look into it more soon, but with both of our fluids being black, I figured it was worth mentioning.

BAIBAICOP said:

Not sure about abnormal rear. When I had tires replaced at 2250mi I had 80% left on the rear brake pads. At face value that sounds like a lot of rear brake pad wear to me, but I have nothing to compare it to. The tech didn't say anything about it being abnormal when he gave me the numbers. I cleaned the rotor (which looks fine) and only the expected amt of brake dust came off.

The fluid in the res is pitch black - I'll change that and see how it goes. Suspect you're right about it being nothing - after all if it were a catastrophic failure in waiting I'd already be on my ass from it.

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Your on the right path I'd bet. Change the fluid, and money says your golden.

CrashAstern said:

For what it's worth, my rear fluid reservoir is also jet black - but I never made any direct observations of the rear rotor being hot.

Probably related, but my rear brake is now spongy - almost as if there's air in the line, but I haven't leaked anything out. It doesn't actuate anymore at all, e.g. it won't stay put if I use the rear brake in neutral on an incline. My schedule should open up a bit and I can look into it more soon, but with both of our fluids being black, I figured it was worth mentioning.

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I probably should have mentioned that the pedal feel is actually very good, awesome even compared to Sato rearsets (no springs, direct pressure on rear M/C) on any other bike.

our bikes have rear brakes?