Bicycle disk brake proformance?

Question

well i got a Specialized Rockhopper Disk for my birthday and i was riding it and my rear brakes suddenly lost power.

i was thinking that maybe some oil or lube of some kind got on the disk but i could find no trace of oil on the disk or pads, my rear disk seems to be a little out of true also.

I have Avid BB5 mechanical Calipers

Answer 1

It could be a bunch of things. If this happened during one of the first rides, it is normal. Discs take some time to break in.

Warped rotors are also a way of life. The heating and cooling as you use it will do that. Just gently bend it back- it takes VERY little force.

You really shouldn't readjust discs unless you really know what you're doing. Depending on the dealer that sold the bike, they might consider it to be something that voids the warranty. My guess is that checkups at the dealer are free for some amount of time, so take advantage of it!

Also, remember that rear brakes are for controlling speed and for handling, not for stopping. This is why most bikes have smaller discs in the rear. 70% of your stopping power should be at the FRONT wheel.

EDIT: Slime doesn't repair punctures very well, and eventually it will foul your valve as well. It is far cheaper and better to replace the tube. Make sure you check inside the tire for throrns or other stuff sticking through it.