CT5-V 5BW tire wear running the track alignment on the street.. time for an in-between alignment?

[thefleshrocket]

I did a track day (four 20-minute sessions) with my 5BW with the street alignment, at WWTR near St. Louis, back in September 2023. It chewed up the outside edge of the passenger side front tire, so much so that I replaced it after the track day. I then had the track alignment installed. I did another four 20-minute-sessions track day at WWTR, and then I did a "run as much as you want" track day at NCM, where I probably did about 110-120 minutes of track time. In between there, the 5BW had its winter wheels with all-seasons installed, for, I would guess, about 2000 miles. The 5BW now has about 7400 miles on it, and the inside edge of the passenger-side front tire is slightly corded (one tiny spot poking through) and the driver's side is barely better. But the tread not near the edges of the tires has plenty of meat left. The rears look okay, well worn consistently acorss the entire tread. Tires are the factory PS4S.

It's my understanding that toe causes inside edge tire wear, not camber, but the track alignment that I had my alignment guy set is as follows, which is only 0.1 degree total toe:
Front: -2.5 deg camber, 0.1 deg total toe
Rear: -1.5 deg camber, 0.1 deg total toe

Now maybe it was tire pressures. At WWTR, I was in the upper 20s (like 28 or 29) when going out onto the track, and into the mid-upper 30s (like 36-37) by the end of the session. So hot was where it was supposed to be, but cold was a little low. Not sure how else to handle that, though--when the tires are picking up nearly 10 PSI after a 20-minute session. I don't have any in-car video from NCM (so I can see the gauge cluster) so I don't recall what tire pressures I was running there, but I assume comparable to WWTR.

The street alignment is clearly not optimal for outer-edge tire life at the track, but the track alignment apparently isn't compatible with the inner edge for street use. I can't justify a $100 alignment before and after each track day, so I'm hoping that there's a mid-way compromise in front-end alignment. There's not a whole lot of change I can make with the toe, since the track alignment is only 0.1 degree total toe. The 2.5 degrees of negative camber is pretty aggressive, but, again, I thought that it's toe that kills tires. Maybe dial back front negative camber to 1.5 degrees, to match the rear?

 

[SIR ICE]

These cars, much like the Gen 6 Camaro, have very aggressive Akerman angles, This makes the inside tire turn-in further than the outside tire, creating a lot of toe-out when cornering. This helps the car turn-in better but can tend to eat the inside edge of the tire. If the track has more right and than left turns, the right front will show more wear. The opposite for more lefts than rights. Of course the more static toe-out you run the worse it gets.

 

[thefleshrocket]

These cars, much like the Gen 6 Camaro, have very aggressive Akerman angles, This makes the inside tire turn-in further than the outside tire, creating a lot of toe-out when cornering. This helps the car turn-in better but can tend to eat the inside edge of the tire. If the track has more right and than left turns, the right front will show more wear. The opposite for more lefts than rights. Of course the more static toe-out you run the worse it gets.

So you think most of my tire wear is from the track, not the street? WWTR is a counter-clockwise track, and it is tough on the passenger-side front tire for sure--especially the banked oval section. But NCM is clockwise, and seems less prone to tire abuse.

Pics of my tires included for reference.

 

[SIR ICE]

.1 degree of toe-out is very conservative. I think most of your inside wear is from the track not the street.

I don't see any cord showing but that could be the photos.

I would say the rear tires were a bit over-inflated, perhaps by 2 to 3 psi.

The front look like they've taken a bit too much heat on the shoulders. Maybe too much understeer or staying on track for too many laps.

 

[Mcard23]

I had the same issue on my inner fronts late this fall. No track time on the tires but track alignment….was told the inner shoulders on the TPC spec get hot and will have accelerated wear even on the street. I went back to a street alignment (tires were only like a year old). Had tons of tread on the tire but was showing wear bars. Alignment was checked and no toe issues either

 

[CT4-Venom]

That tire looks great. At least another 20k miles left on it! Might even be snow ready at this point.

 

[SIR ICE]

Thanks for sharing your learning experience.

Just a wild guess, but just maybe using a Track Alignment on the street was the cause of the problem, much like using a Street Alignment on the track and expecting a different outcome.

 

[BigShark]

Yeah I'd go with a compromise alignment somewhere between street and track settings - maybe -1.8 to -2.0 degrees front camber instead of the full -2.5 since you're doing more street miles than track time.