Hello everyone,

I started taking my Outlaw calipers off today in preparation for a caliper seal rejuvenation, and one thing came to mind that I've never really came to ease with. The last day I was at the track, I was down to my last 25% of pad material and I've always noticed that the part of the pad that gets worn away more is the top edge. So after a while, the pad side profile almost looks like a wedge instead of being perfectly rectangular.

I think I understand what's going on here. As the car is moving forward and the brakes are applied, the pad & pistons are dragged downward. When the brakes are not being applied the face of the pistons are parallel to the face of the rotor and pad, but as the brakes are applied it gets dragged downward causing more wear on the top.

As we wrapped up and headed home, I noticed that the upper piston on each side of the rotor were stuck in the bores. I believe this was due to how little pad material I had left, how far the pistons were protruding out of the calipers, and that they were getting forced downward. I free'd them up, but still I'm not to at ease with this behavior. I worry that the stainless steel piston will start to gouge the inside of the aluminum caliper over time.

Is anybody else experiencing this running a big brake kit (BBK) on a R56 or R53?

My calipers are perfectly on center with my rotors. Is this normal or am I correct with my logic?

I've noticed that Wilwood sells brake pad shims that would prevent the pistons from protruding so far, but Outlaw does not. I can make my own, but it shows that perhaps Wilwood has thought this out. I've even seen some Lotus folks use this method on their brakes. What does everyone think?

 

All square or equal bore calipers experience this to a degree; pad taper wear.

It's a simple situation of pressure. The leading edge bites fresh meat and the trailing deals with a slight boundary layer of gaseous material that prevents the clamping from being so equal.

Differential bore calipers counter this by using a larger piston on the trailing edge for more clamping.

There's really nothing you can do to 'fix' it. Just work around it. Flip the pads after so many miles/sessions and don't let them start to taper. They do and it goes down hill quickly. Also using pad spacers an control the piston extension/cocking issue as the keep the pistons in the bore longer for improved compliance.



The DT/Outlaw kits are the same as Wilwood FBDL pads.
http://www.tceperformanceproducts.com/brake-pads/

 

Looks like I was close in my estimation of what's happening. Thanks for breaking it down Todd!


So I could order a FBDL pad spacer and it will work with my Outlaw 2000 caliper? I'd rather just order some if someone has made them then trying to make my own this winter while I'm in track season hiatus.

 

That's correct. They all take the same pad.