[RKDinOKC]

Weird tires. Running Dunlop Direzza Star Specs on the 928. Have had them about a year. After talking to a guy with an S2000 I lowered the cold pressures from 36 to 32 and they were a LOT faster. Ran them at 32 cold for most of this season. However at an autocross with some really tight turns I got some folding on the fronts. Folding is were the tire feels like it is skipping and the side walls get worn. Because of the wear going up the sidewalls I increased the front pressures back up to 35 cold. Then at the April autocross the front tires evidently got really hot and blistered the fronts down the center of the tires. Typically a sign of pressure being too high.

Well, got some new Direzza Star Specs and started at 30 psi front and rear cold. Did a 150 foot skid pad Saturday and the tread skuffing looked good. I got scuffing down to the triangle on the sidewall but not into it showing proper pressure, ie, using all of the tread.

Today, the day after the Skid pad I autocrossed and took my tire gauge and pyrometer. The first set of four runs I just let the tires run since I was starting at 30 psi cold and wasn't too worried about either skuffing the sidewalls or blistering the centers. My first lap was the fastest and fourth was the slowest. The last set of four I checked temps and pressures immediately after each run. Temp wise the results were the same 140 - 154 - 140 across the tread typically meaning too much pressure.

The pressures were a little different. after the first lap the pressure only increased to 31 psi. I left it at 31 psi and made the next run. Temp increased to 35 so I dropped it back down to 31. Same for 3rd and 4th runs. My times decreased on each run in the second session.

The really interesting thing is that internet searches are showing most are running near 40 psi hot on these tires to keep from skuffing the side walls. Just seems really weird to be running such low pressures. I'm thinking 30 psi hot will be even faster than the 31 I set them at today since the center tread temps are still a bit higher than either inside or outside tread areas.