my promax disc seem really weak

[cerpindicular]

I have a 04 Fuji outland disc with promax brakes. Got the bike used last night and the brakes were loose enough that i could push it while yanking the breaks and they tires still rolled easily. I took the pads out and scuffed them pretty good with sand paper as well as the rotors put everything back together and attempted to readjust them (first time dealing with disc ever) Got them quite a bit tighter but still can only barely get the rear to lock (only for a second or 2 on gravel) and they front is still pretty soft. Is it supposed to be like this? Like i said i have never messed with disc before so maybe i expect to much from them but I have a old schwinn mountain bike that i can stand on its nose and balance there and it just has some old tektro side pull brakes. Any advice?

[jcaino]

The only thing I know about Promax disc brakes is that they're spec'd on some of Redline's new bikes and my local shop tried setting up a few - they were so bad that they ended up getting Redline to swap out ALL of the Promax calipers for Avid BB5's.

How are they adjusted? If you can't adjust them any more without getting pad drag, it is possible that the pads/rotor may need contaminated. If that's the case, you can bake the pads (or get new ones) and clean the rotors really well with brake cleaner.

Also, how is the pad life? I've had some experience with cable-operated brakes that when the pads are close to the end of their life that they just don't have much grab.

[joeinchi]

You need to bed in the pads. Basically, eight hard stops which will generate enough heat to transfer pad material to the rotor surface. This transfer of pad material is what gives your discs their grip.

Generally, you don't need to clean discs unless there is a slick contaminent on the surface. In those cases, use rubbing alcohol--not sandpaper. Now, that you've got them tightened up, you just need to break them in.