What part of the clutch is being broken in during break-in period?
 

Just bought a new ACT Xtreme Clutch and am breaking it in for like 500 miles, then slowly work it harder. But am curious to what part of the clutch is getting the most of the break-in. It would seem to be the disc, but wasn't sure if the pressure plate was breaking in too.
M-P

the disc has to wear into both the pressure plate and the flywheel. they are all being broken in together.

exactly.

The materal on the disk is finishing its cure , (chemical harding of the composit ) and seating or wearing in to the flywheel and preasure plate .

what is the proper technique for breaking in a clutch....I must admit I don't think I have ever done it.

Do not slip the clutch alot so there is no high heat build up . no drag starts . do not hold the clutch in while stoped for a long period of time, take it out of gear .The material brakes are made from also needs curing .

baby it for about 500 miles. as little slipping as possible and no full throttle especially at high rpm. i dont see a problem with holding the clutch in, that just wears your throwout bearing.

Holding the clutch in when new will burn hot spots if the high spots are draging alittle . This will happen if the clearences are small and the disk materal is not even in thickness .