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I’m shaking down my lemons car at thill today, and have pf06s on it. With no bed in, I took em out for a 7/10ths session and got bad vibration. Came in, swapped rotors (cheap chinese -> balo) and did another session. Same deal.
We’ve got no cooling, and no dust shields.
Would like to hear others’ experience.
While I could see vibration from a switch in pad types on a given set of rotors, I doubt that the pads are the cause since you replaced the rotors.
What is th condition of the rest of the front suspension (control arms, CABs, struts, tie rods. bearings)?
So first time out you had old rotors with new pads, then swapped to new rotors with the same 06s for the second session, right?
It’s always a good idea to change rotors with a pad compound change. When you did change the rotors, did you clean the pads? I would suggest roughing them back up with steel wool and some brake cleaner to make sure you get any remnants of the old compound off. Same with the rotors.
I’d also check the control arms at all three points.
Cause might be uneven pad deposits. Fix is often a half dozen good hard braking efforts, as in 120-40 at threshold.
Background. I change pads a lot because I’ve been experimenting with them. Last Spring I got the behavior you described and couldn’t find the cause. I did some research on warped rotors and found some interesting pieces that said that warped rotors usually indicate some other problem that is preventing the rotor from spinning straight. Usually the problem is not warped rotors but uneven pad deposits. You can often detect this by looking for a “blotchy” appearance on the rotor.
When the brake shuddering occured I started driving and braking really cautiously, trying to figure out what was going on. Not knowing that what I needed to do was drive and brake hard. Once I did start braking hard, the problem went away.
I’m about half way thru a set of front PFC06’s. They behaved just fine, although I thought that they would last a little longer.
Hmm, I think you’re right Ranger.
We decided to ride it out, and 1 more session worth of vibration ended with smooth normal braking. Skeen, the original rotors were new, but now that I think of it they did have HT10’s on them for driving around the block while the pf06’s arrived. Maybe the compounds did disagree, and it took a while to get the pads happy again on the new rotors?
The new rotors that are on the car are happy, so I’m going to leave them be 
Thus far I like the feel of the pf06’s, but it’d be disappointing if they don’t wear as awesomely as the bimmerworld site claims.
WRT front suspension, most of it is unknown stock stuff from a 170k mile car (hey, it was only $200!). I put new control arm bushings on it since the old ones were shot. I guess I could rationalize new control arms for “safety”, but they definitely wouldn’t fall into the $500 budget otherwise.