[Pat]

Here is my car as it sits now:
BFG R1-S tires at 35.5 psi hot
Stock suspension
DTC-60 pads
Togue Factory brake ducts
Motul RBF-600 brake fluid
Camber plates
2.6* of front camber
1.3* of rear camber
The car is pretty much stock other than that, and I do the pedal dance before pulling onto the track.
Recently I was at High Plains Raceway and noticed something funny with the tires. It was my first day on these tires. They are four years old and have been heat cycled by The Tire Rack. Before yesterday they had maybe one or two sessions on them. In the morning ambient temps were in the upper 40s. By the end of the afternoon it was around 70.
I experienced some graining with the front tires. Once the car had warmed up about three or four minutes and I started building some speed, the front tires would start to feel like they were driving on small gravel pieces. They would sound louder and rougher and I could feel it through the steering wheel.
When I brought the car in I could see a strip of clag all the way around the inner third of the tire, but the outer two thirds of the front tires looked perfect. The wear on the outer and inner shoulders looked right where they should be.
There were two turns where this behavior was especially noticeable (7 and 11). They are both very long turns. I would enter the turns with almost none of this bad feeling from the front tires, but as I would drive through each of these long turns, I could slowly feel them graining. By the end of each turn it feel fairly rough in the front end and the grip would slowly go away as I proceeded through each turn. By the end of these turns the car would be understeering significantly.
It seems to me like these long sustained turns heated up the front tires past the point of where they should be. That said, these are pretty serious tires and I would not expect that type of driving to be a problem for them. Especially on my lowly car with lower ambient and track temperatures.
I measured temperatures on the inner shoulder, center and outer shoulder of each tire at the end of a session. I came into hot pits quickly, stopped quickly and jumped out to measure as fast as I could using my cheap China Freight IR pyrometer. Each of the four tires varied less than ten degrees across the tread. IIRC most were about five degrees in variance.
I don't have data acquisition available for review. If you need to see a video of my driving i can post one, but doubt it's necessary to figure out what's going on with the tires. I've been driving on tracks for 17 years and instructing for much of that.
FWIW, I spoke with a long-time national champion racer about this yesterday at the track and he couldn't figure it out.
What theories do you guys have for this kind of tire behavior? I'm kind of drawing a blank. My only theory is I need more camber up front, but honestly, I don't really think that's right based on tire temperatures.
CSG Mike already responded in another thread (thanks!) saying that he thinks it's just the nature of the stock suspension causing the car to understeer and therefore overwork the front tires. What other thoughts do you guys have?
TIA