Originally Posted by
RBLove
The new crop of 21.5's definitely appear to be faster than last years 17.5's.
I can't say it's quite that drastic... But then again, at my last race in Omaha, my USGT fast lap using the new TSR 1.0 was only 2% slower than my 17.5 TC fast lap using the previous version TSR. I'm guessing that a large portion of that was due to less grip from the USGT tires.