Street Brake Pads On Track
Recently I had an unintentional opportunity to test performance of some street brake pads on the track. Due to an oversight on my part I failed to secure spare brake pads in time, and I happened to visit Watkins Glen which is a brake heavy track.
Hawk DTC-60 - Baseline
I started Friday on these pads. They were pretty worn and I was concerned that I would not make it through the weekend with these.
I ran the entire Friday which was an advanced day with tons of track time. By the end of Friday the pads looked like they were wearing out but still had usable life. What I did not know was the pads were tapering and the inside bottom edges in particular - the ones hardest to see - were almost down to the backing plate.
Lesson 1: Actually remove pads from calipers to check their life.
By afternoon on Saturday I was hearing metal on metal noises coming from the brakes, and when I took the pads out I saw two of the four worn to the backing plates.
The next pads that I put on the car was a set of Hawk HP+ that came with the car originally, presumably the brake pads that the previous owner used before upgrading to DTC-60. These had about 1/4 to 1/3 friction material left.
Pedal feel with HP+ pads was initially much better (stiffer) than that with DTC-60. This was the most surprising discovery of the day.
HP+ lasted about 15-18 minutes before fading. I could get 1/2 to 2/3 of a session of hard driving out of them.
The pads wore quickly - I started with them having maybe 1/4 to 1/3 life and by the end of the day the pads had just worn to the backing plate in one spot.
With both sets of Hawk pads expended it became necessary to procure pads from a friendly Advance Auto Parts store. I bought a set of Wearever Silver semi-metallic pads and a set of Wearever Gold ceramic brake pads. The sales rep said ceramic pads would tolerate heat better, and Golds were also twice as expensive as Silver pads ($30 vs $15).
I started Sunday on the Gold pads.
The pads lasted about 10-12 minutes before fading. Pedal feel was actually quite good while the pads were not too hot. I managed to set my best time of the weekend running Gold pads, and by then I lost significant tire grip.
Lesson 2: Ceramic Advance Auto Parts pads are actually not bad.
By lunch Sunday a strange thing happened - after I bled the brakes the pedal was going to the floor with about 1/3 of the expected resistance. After removing the pads they were all cracked. Presumably the pistons was bending the backing plates when brakes were applied. Pads still had a lot of friction material left on them, but were no longer usable.
Lesson 3: "Regular" auto parts stores' pads don't last very long, and they can become unusable in ways other than wearing out.
Finally I went to my remaining set of Wearever Silver pads for the second half of Sunay. These pads were pretty questionable off the bat - I smelled them on the second lap of each session in hard braking zones. The pads provided stopping power but I backed off the pace as I had much less confidence in them even compared to Wearever Gold pads. I never really experienced a moment of "no brakes" but I also never committed to hard braking.
Lesson 4: In emergency pad purchases go with higher temperature pads.
Do take extra brake pads to Watkins Glen. Do order brake pads in advance. Do get ceramic auto parts store brake pads to save a track weekend. Hawk DTC-60 pads seem to be spongy, I am not impressed with them very much at all.
Soft pedal is not the only issue I have had with Hawk DTC-60 brake pads. At the next event friction material separated from the backing plate on a brand new set of pads.