I've been tracking my car quite a bit this year and want to keep a close eye on my pads to be sure I change them before it gets too late. At what thickness do you recommend that they be changed. Also is there an easy way to inspect them (other than removing the wheels). On the back I can see the outboard pads through the wheels (is pad wear similar inboard to outboard?) but the fronts are not as readily accessible. What do you guys do?

 

Once you get to about 3-5 mm on the outboard pad, you are basically done, ready to hear the screamer bars. I had front and back (inside and out) pads wear out simultaneously. This is with occasional tracking, autocross and street use.

If you start to really punish the OEM pads they can use almost half of the pad in one day, which would force you into unnecessarily changing the pads "just in case". I would just keep an extra set for a track day. It's pretty easy and you'll need to bring a jack, torque wrench (for wheel nuts), two wrenches, C-clamp and 3/4" socket wrench extension (or special rear brake piston retractor).

 

Pull the wheels off and look, especialy before a track event. I never start a track session with less than a 1/8" or a bit more of pad. I usually get pretty even wear front to rear but many report uneven wear so to be safe you need to look at each wheel.