How to select the right motorsports brake pads

“As much as I’d love to tell someone there’s one brake pad that can do everything, the reality is when you’re trying to compete in multiple venues, you’re going to have to weigh compromises when it comes to brake pads.” That’s Hawk Performance’s Mitch Bloom lamenting the bane of the brake market the world over: the search for the do-it-all …

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I autocross a lot and once a year one of the chapters has an "enduro", a five laps event.  That is the most severe usage my brakes get.  At one of those events, with a layout that had a lot of longer pulls, I ended up with some brake smoking as I pulled off, but a slow idle around the parking lot for a few minutes cooled things off nicely. 

The car builder liked Hawks, think it was HP-1, or HP+, unsure?  In 2006.  The car is my daily, and the heavy dusting and squeaking make me rethink that choice once the rotors got too thin, after the second set of pads.  I also didn't like that those Hawks really needed a little bit of heat, one or two good applications, before they really gripped.  Not optimal for street use - I had a set of even more track-ish pads on another car and nearly rear ended someone when the onramp backed up, and I was STANDING on those brakes with little effect.  So I went back to Carbotech 1521's "high performance street compound", used to be called their Bobcat line.  No change in grip from cold to quite warm, far less dusting, pretty much no squeal, and the lower torque offers me more range of modulation.  Like most makers, if you want to go to a more aggressive pad for track days, they offer higher temp pads with a compatible compound so that you supposedly do not have to grind them clean and re-bed the pads.  And these have lasted in one set as long as two sets of those Hawks did, with plenty of pad still left.  It's worked for me.

OK, I know the correct thing to do is marry a set of pads to a set of rotors but how bad is it if you keep the same rotors you drove to the track on and change just the pads for a track session?

I've been street driving my civic for almost a year with Carbotech AX6 autocross pads. They've worn down the front rotors, so I'm going to swap on some used ones tomorrow for the track sprint on Sunday. 
The replacement rotors were used with some Hawk HPS pads, so I sanded to bare steel with some 150 grit. 

edmagoo said:

OK, I know the correct thing to do is marry a set of pads to a set of rotors but how bad is it if you keep the same rotors you drove to the track on and change just the pads for a track session?

That depends on the pads involved, if they're both from the same manufacturer, often they'll publish which pads have compatible compounds. If you're switching between incompatible compounds you'll probably notice rapid rotor wear and/or a big reduction in braking performance when you switch.

Here's my luck with dual-duty pads so far:

EBC Yellowstuff on AE92 Corolla:

• Pros: Totally unflappable on track, not bad on the street, last a long time, affordable
• Cons: Braking power that ramps up rapidly with temperature on street or in autocross, fairly high dust, need to be mindful of rotor heat because these pads can destroy a set without making a peep.

Powerstop PST on Toyobaru:

• Pros: Great street manners even at freezing temps, affordable
• Cons: Wear quickly, very dusty, not really fit for track use - performed decently but wore away roughly all pad material and caused heavy rotor wear on the first track day, even with brake venting.

Powerstop PSA on Toyobaru:

• Pros: Great street manners even at freezing temps, affordable
• Cons: Wear quickly, threaten to blot out the sun with dust, can still get some fade on long track sessions even with venting, not easy on rotors.