Locked the Rear Brake Today

[thebleakness]

I was racing a friend through the woods today and I was riding like I've never have before. It seems every time I hop on the bike I feel so much faster than the day before. I was keeping a good pace in front of a few fast B riders (I'm C class, not sure for how long though) and feeling great. No crashes today! Some cool video though, I'll see if I can find it...

Well after literally 5 hours straight of riding my bike started loosing power...fast. It became so hard to keep riding fast and I thought the bike was going to blow up. I stopped and what do I find....

FIRE! My brake pads were literally on fire and the rotor was glowing red. It was totally locked up. We let it cool down for a few minutes and then opened up the caliper vent and steam shot out. It was incredible, it happened so fast and I'm not totally sure why it happened. My rotor is now tempered a nice blue color.

I disconnected the brake and continued riding too! Good times...

Has this happened to anyone else? What can I do to prevent this from happening again? Better pads? Higher quality brake fluid?

Awesome, awesome ride though!

[strider80]

High quality fluid is always a good idea.

I think you are due for a caliper rebuild or a new caliper. The piston and caliper surfaces are probably damaged and got hung up, sticking the brake on. Take it apart and take a look.

What was the condition of your pads and rotor before? If the pads and rotor get thin, the piston sticks out further and can get cocked easier. Also look at your caliper and pad pins, make sure they are smooth and the caliper pins are lubed.

[canyncarvr]

Any chance it's not the brake system..but a foot draggin' rider?

[kawagumby]

I am a foot-dragging rider and the KDX rear rotor is just too sensitive. I have to be sooo careful about full release after brake slides or I fry the brakes bad. None of my other bikes have given me the grief of a KDX rear rotor (the blue rotor blues for sure).
Things I have done to help the situation:
1. Use DOT 4 synth 500 degree brake fluid.
2. Remove the worthless plastic guard to allow more air flow.
3. Drill out the rear brake rotor to increase cooling surface.
http://kdxrider.net/forums/modules/albu ... .sized.jpg

4. Use carbon pads.

Having said all of the above, I have never had a rotor lock up, just the opposite...the fluid boils and nothing happens - no braking at all. So you might just have a mechanical gremlin as suggested earlier.

[thebleakness]

Any chance it's not the brake system..but a foot draggin' rider?

I thought that but I checked and I don't really do that.

I did however find the problem...I think. I had hit some g'outs and other hard edges really hard that I could feel the rear end clank. I think in one of those hits the axle tweaked abit and moved out of alignment. My right side snail adjuster was maybe 3/16" away from resting away on the peg. I think this skewed the rotor and rubbed along the pads. I rode it for an hour and half straight on monday without problems so I think I'm good!