Vibrations w/ disc brakes
 

Hi,

I got a pair of Hayes CX disc brakes on my touring bike.
Brakes alright, only one uncomfortable/strange thing: front brake makes vibrations when braking: as it the pad was slipping on the disc before catching it for good, the phenomena is reduced if I apply the brake really gently and progressively, or if I keep it applied: at some point the vibrations stop.

Braking in rear is smooth.

What should I look into?
- clean the rotor in case it is compromised with any accidentally leftover grease or oil?
- sand-paper the pads?
- the rotor is a 6-screw one adapted on my centerlock hub with a Shimano 6-screw-to-centerlock adapter, should I verify the centerlock is tightened enough?

What else? I know for sure that cable and housing are clean and properly lubricated without any weird angle or whatever.
Any other idea?

Is the caliper correctly aligned with the rotor?

Checked that when changing the cable recently: loosened the two bolts that link the caliper to the fork, squeezed the handle and tightened. So I would say yes.

Try using the pad adjusters to align the caliper. Adjust each pad so that it's touching the rotor (loosen the caliper mounting bolts first), and then tighten each pad so that the rotor is "clamped" by the pads. Then tighten the caliper bolts, and back out the pads to clear the rotor.

rotor out of true?

I have the exact same problem on my new road bike. It seems to only occur if I have to do moderate to heavy braking when I'm going downhill at >25 mph.

If you find a solution, please post it.

Thanks,