tire issue?

[marlin]

Noticed a tire abnormality and need help with clarification/cause. Khumos that have about 1100 miles on them. Photo is of the left driver side tire. Other tires do not show same pattern. Running 21 psi fronts (255/40/17), 22 rears(315/35/17). Looks like I ran over strips of caulking? I did do a track day 2 weeks ago, hooked on driving beginner, with braking and figure 8 exercise. 4 track sessions. 1 high speed (for me) spin out. 3 hour drive to track should have warmed up tires. Did I cook 1 tire? Suggestions as to what to do if anything?
42146

[Gumball]

Can't tell for sure in that picture, but it appears to be excess rubber that was scrubbed from the tread. I'd drive it for a while, keeping an eye on further wear and feeling, and it will likely disappear.

[dvcamm]

Noticed a tire abnormality and need help with clarification/cause. Khumos that have about 1100 miles on them. Photo is of the left driver side tire. Other tires do not show same pattern. Running 21 psi fronts (255/40/17), 22 rears(315/35/17). Looks like I ran over strips of caulking? I did do a track day 2 weeks ago, hooked on driving beginner, with braking and figure 8 exercise. 4 track sessions. 1 high speed (for me) spin out. 3 hour drive to track should have warmed up tires. Did I cook 1 tire? Suggestions as to what to do if anything?
42146

Search "tire worms"

[avgjoe]

Left front or left rear? I would guess left rear. It appears to be like Chris said melted rubber from your tread. It is completely normal when you get some real heat into the tire. Your 3hr drive to and from the track did very little to warm up the tire compared to the warming you did on the track. When these come off of the tread and are deposited onto other non-tire places like the track or water pump pulley the're called tire turds. It was probably worse before you left the track and you wore some of it off on your way home. The more seat time you get the more this will happen. The spin didn't help but it shouldn't hurt a set of street tires.

Now do your self a favor and get out there an make more tire turds.

[marlin]

Thanks for the reply to the thread. The tire was the left front, but all the wheels did show heat from the track. The worms or turds have worn away with more miles. One of the best things about building and using this car is all the things I've learned that I didn't even know I didn't know. Back to the track tomorrow but It's the wife's turn to drive her Cobra trainer, a MX-5 Miata. Her choice, she is welcome to drive the Cobra too. Have fun!
Marlin