New brake pads on used rotors, What is the procedure for bedding? Options

[ThePaintedMan]

I guess this one's probably best for Eric, but I'm curious what the consensus is on the topic, so feel free to chime in. If one were to install a different compound of pads on an existing rotor, is there anything that needs to be done so that they will bed correctly? The rotors are in good shape and in my opinion aren't in need of turning, but when you install a different compound of pad, isn't there a difference in the chemicals that are transferred to the rotor? Is there a way to clean a rotor so that any old residue is removed and the new pads will transfer that initial layer of chemical material to the rotors to allow them to be properly bedded?

I've seen some guys put better pads on at the track before a DE, but use the same rotors. Is this a no-no?

[pcar916]

As long as they're truly flat, I'll rough the rotors up a bit with a block and 400 grit emory cloth. In my experience, this is much easier than putting new pads on new rotors.

Likewise new rotors and old pads work well too as long as the pads are still flat. In that case I rough up the pads a little as well.

Point is, I'll put new pads on old FLAT rotors every time. If they're carbon pads then the usual procedure applies. Go fast and bed them hard several times. I do the same with Carbon-Kevlar pads but at a lower speed... like 75 instead of 100. Street pads I just drive normally (i.e. moderately spirited) and brake not nearly as hard.

Hard braking on new street pads has given me glazing problems as often as not.

Good luck!