Rear brake dragging

[skuzzle]

Today was the first 90+ degree day here.  About 10 miles into the ride home I noticed the bike slowing more than usual at a stop sign.  I turned off on a side road and noticed that I was using about 16kw to go 35 MPH... not a good sign.  Pulled over and found the rear tire almost locked with very hot brakes.  I let it sit for 4 or 5 minutes and also tapped the caliper to see if that would loosen things up.  It seems to get better from time to cool (and/or tapping) so I proceeded about 10 miles to home without using the rear brake.  At home I put it up on a rear stand and found no issues.  The wheel turned freely and the brake worked fine.

This bike is much smaller than my Vstrom, so I suppose it's possible my foot was dragging on the brake.  I think I would have noticed that before now.  (I tend to watch the power meter closely).  I've never had this problem before on 20 some odd bikes over 30 years.  Any ideas out there?

[Brammofan]

I find that I rarely use the rear brake. 
Maybe you should take it to a bike shop to see if it's adjusted properly?

[EmpulseRider]

I never use the rear brake, in most cases the simulated engine braking is enough for the rear IMO. Perhaps something was jamming the brake lever... next time I would jump off the bike and see if the rear brake light stays on.

[Richard230]

My guess is that there is air or moisture in the brake line that is expanding when hot.  Perhaps bleeding the brake line might be worth a try.

[7racer]

Does anyone else hear what sounds like dragging when you just push the bike in neutral?  The vid in moving the Empulse is the sound I'm referring to.  I think mine drags too but will pay closer attention to the power used

[skuzzle]

Does anyone else hear what sounds like dragging when you just push the bike in neutral?  The vid in moving the Empulse is the sound I'm referring to.  I think mine drags too but will pay closer attention to the power used

Most bikes will have a slight amount of dragging that you can hear when you push the bike around.

I never use the rear brake, in most cases the simulated engine braking is enough for the rear IMO. Perhaps something was jamming the brake lever... next time I would jump off the bike and see if the rear brake light stays on.

I wish I would have thought of checking the brake light.  It would be nice if there was a small LED up front so I could see when the light was on.  The Regen is so strong in sport mode that I try to hit the front brakes just hard enough to engage the light.  The fluid pressure was so high when I had the problem that the rear brake lever had virtually no movement at all.

For now I'll just stop using the rear brake until it gets serviced.  Note that I don't use it that much anyway.  For now I'll assume that my effort to get more aerodynamic pointed my toes down and accidentally hit the brake for a short time.  Not convinced that this is the issue as the brake spring is pretty stiff.

[flar]

When I was new to the bike I once mounted my foot on the stop lever instead of the peg.  I noticed it after about 50 yards of travel, but mostly due to thinking it was odd that my foot was a little forward and down from what I was used to - I actually didn't notice the drag from the brake much except in retrospect, it was more my foot position that tipped me off.

[Jeff]

Does anyone else hear what sounds like dragging when you just push the bike in neutral?  The vid in moving the Empulse is the sound I'm referring to.  I think mine drags too but will pay closer attention to the power used

Most bikes will have a slight amount of dragging that you can hear when you push the bike around.

Yeah this actually freaked me out for a while.  Coasting at low speeds you can totally hear the brake pads rubbing.  One of those noises (like the chain slap) that happens on all bikes but with a gas bike there's a hell of a lot of other noises masking it.

[Shinysideup]

The fluid pressure was so high when I had the problem that the rear brake lever had virtually no movement at all.

This sure sounds like a telltale sign of an air bubble in your brake lines. Heat makes bubble expand enough to a) apply the brake and b) leave no play in your lever.

When it's not hot, does the lever distance required for braking lessen when you pump the lever a bunch of times?

I'd ask the dealer, if near by, to bleed the rear line. If your dealer is far away, the process not hard to do once you buy the basic equipment, which isn't expensive.