Using Wilwood bp30's with bp10's?
 

I have my Wilwood proportioning valve turned all the way in to get max line pressure to my rear brakes, but I can't seem to be able to get them to lock up. Granted, I have BP30 pads in my Aerolite fronts and BP10 in the FNSL rears. I switched out the 30's I had in the rear because I was getting a weird harmonic vibration sound when rolling to a stop, or moving forward very slowly. The sound went away after the bp10's went in, I can't seem to be able to get the rears to lock up before the fronts on pavement. I know the front pads are much more aggressive, but I thought I could adjust for that with my proportioning valve. I thought the combination would give me the feel I wanted for the street without the increased wear on the rears between track days. Thoughts?

The BP30s have a higher coefficient of friction, which is also why the rears were making noise under light braking. We've installed a fair amount of BP30 pads on convential non-floating solid axles, and a lot of them made noise.

I wouldn't be surprised if the differences between the 30s and 10s are big enough to throw off your brake bias to the point that you aren't getting enough rear brake before locking up the fronts.

My question is, how bad does it actually feel? If performance feels okay, I wouldn't worry about it on the street.

I had the same issue with my Wildwood set up. I ended up with a more aggressive pad out back to make sure I had all the rear brake my car could handle. I'm sure the 335m tires had something to do with it. Matt's right though, if it's stopping well, it may not be worth the trouble. I was trying to extract all the performance I could get. I gained some, no doubt, but for a weekend warrior, like not worth the trouble. They were noisy and dusty.

I believe the proportioning valve only alters psi ( minimizes it ) at max line pressure. So, adjusting it does not alter rear brake pressure until lockup is achieved, and at that point it decreases pressure to help prevent lockup