[R1LEY]

So I did a track day in the rain and cold this past Thursday at Gingerman, and I noticed on my last session out that the two turns after the straightaways my car would vibrate like crazy. Everything was fine during the 2 previous 30 minute sessions. Car has 48,500 miles on original rotors and I had a new set of powerstop track pads and Supercar3 tires. After getting home and getting the wheels off I noticed this dotted line around the rotor. I assume these are pad deposits, and if that’s the case how do I fix this and prevent it from happening the next time I go?

Here’s the pictures of the front and rear rotors:



This wasn’t my first track day with the car but I previously used the OEM pads and didn’t have this problem. It was also raining and cold and I wasn’t going as fast as if it would’ve been warm and dry.

[rotis]

Did you bed the pads after installing them? It looks like they started to get warm enough to begin material transfer, but didn't quite get there.

[R1LEY]

Yeah I bed them in the day before. Does that mean that maybe a couple more laps around and it would’ve taken care of itself? It wasn’t very confidence inspiring and the track was super slick so I just called it a day after I started feeling the vibration. Also could’ve been the track finally starting to dry off a little by then as well I suppose.

[cdb95z28]

I've seen this happen with the Powerstop Track pads. Do you use any of the nannies? If so they use the rear brakes to settle the car down. This can cause overheating of the rear brakes. Also, do you do enough of a cool down lap after the session is over? Some events don't give adequate cool down time. If this is the case, drive around the pit area or if you can a nearby road where you can get more cooling to bring the hot lap temps down.

[Timbo-1LE]

Ditto above and I gave up and got aggressive pads and it all went away. GM is a bit nuts on the bedding procedure, there is no way you could do it unless you lived by empty country roads...

[R1LEY]

Yeah I started the day in PTM Wet, but quickly didn’t like just how much it cut power and stop the car from sliding even a little bit and switched to PTM Sport1 and eventually Sport2. The problem though, was that I could feel it in the front too. I still did a cool down lap, but it was 45 degrees and raining steadily throughout the day. The next time I go, I’m going to use the same pads again and only go when it’s dry and a little warmer out to see if it happens again. It’s sounding like I maybe didn’t bed them well enough? I doubt I was overheating them though because my best lap around Gingerman was 2:19 LOL

[sr71bb]

Originally Posted by R1LEY

So I did a track day in the rain and cold this past Thursday at Gingerman, and I noticed on my last session out that the two turns after the straightaways my car would vibrate like crazy. Everything was fine during the 2 previous 30 minute sessions. Car has 48,500 miles on original rotors and I had a new set of powerstop track pads and Supercar3 tires. After getting home and getting the wheels off I noticed this dotted line around the rotor. I assume these are pad deposits, and if that’s the case how do I fix this and prevent it from happening the next time I go?

Here’s the pictures of the front and rear rotors:Attachment 1067257

Attachment 1067258

This wasn’t my first track day with the car but I previously used the OEM pads and didn’t have this problem. It was also raining and cold and I wasn’t going as fast as if it would’ve been warm and dry.

Well any type of vibration when braking normally is associated with the rotor being out of balance or having high spots on the surface. These HIGH SPOTS will get HOTTER than the rest of the rotor when braking. IT looks like that is the deal with these rotors. If you have never had them turned you probably can go ahead and do that. I would HIGHLY reccommend the OEM stock pads especially if this is a DUAL use vehicle. I got about 19K miles out of them and roughly 15 track days with the STOCK pads.

I changed them out with HAWK 5.0 PADS thinking this would be an improvement and while the initial BITE was a little better they did have some slight fading issues so when the time comes I will be going back to OEM original pads.

[Junkyardspecial]

What pads exactly? Are these the z26 powerstops? Because they are NOT track pads.

[R1LEY]

These are the powerstop track day pads. I use the Z26 for daily driving, but swapped to these for the track day.

[R1LEY]

Originally Posted by sr71bb

Well any type of vibration when braking normally is associated with the rotor being out of balance or having high spots on the surface. These HIGH SPOTS will get HOTTER than the rest of the rotor when braking. IT looks like that is the deal with these rotors. If you have never had them turned you probably can go ahead and do that. I would HIGHLY reccommend the OEM stock pads especially if this is a DUAL use vehicle. I got about 19K miles out of them and roughly 15 track days with the STOCK pads.

I changed them out with HAWK 5.0 PADS thinking this would be an improvement and while the initial BITE was a little better they did have some slight fading issues so when the time comes I will be going back to OEM original pads.

Yeah I should’ve gotten the OEM pads again, I had read good things about the track pads and they were cheaper so I thought they would be ok.

[sr71bb]

Originally Posted by R1LEY

Yeah I should’ve gotten the OEM pads again, I had read good things about the track pads and they were cheaper so I thought they would be ok.

A little more of an update. I ran my SECOND track day with these HAWK STREET 5.0 pads and it confirmed to me that they DEFINITELY do have some fading when hot. We were running 25 minute track sessions at EAGLES CANYON RACEWAY which has 15 turns in it and a 1/2 mile straightway and I noticed some degree of fad towards the last 5 minutes of the session. It was predictable but of course but not desirable compared to STOCK pads.