Rookie Chase Elliott was the fastest in Friday’s Sprint Cup practice at Michigan International Speedway with a lap of 201.630 mph.
The practice featured the debut of rule changes for this weekend that NASCAR intends to employ next season.
Those changes are:
- Shortening the spoiler from 3.5 inches to 2.5 inches.
- Resizing the deck fin to match the spoiler size.
- Splitter reduced to 2 inches.
- Reduce skew generated sideforce by setting rear toe to zero.
There also is a new tire from Goodyear to match the changes. The tires were confirmed in a May 17 test at Michigan with Aric Almirola, Austin Dillon, Kyle Larson and Truex. Compared to what was run at Michigan last year, the new tire features construction changes to give the cars more grip.