NASCAR makes its first visit to a 2-mile speedway this weekend as it closes out the West Coast Swing at Auto Club Speedway.
Both Cup and Xfinity teams will be in action and they will each have a new tire combination.
While both series used this left-side tire code at Darlington last year, this is the first time they will use this right-side tire code. Compared to what was run at Auto Club last year, both the left and right-side tire feature construction updates to bring them in line with what is run at other speedways.
The right-side tire is a multi-zone tread tire, featuring two distinct tread compounds on the same tire — one for heat and wear resistance on the inboard two inches of the tread (Endurance Zone) and one for grip on the outboard 10 inches (Traction Zone).
“Fontana presents multiple challenges for teams as far as tires are concerned,” said Greg Stucker, Goodyear’s director of racing in a press release. “First, with NASCAR’s new rules package and more downforce on the Cup cars, observing our minimum recommended air pressures becomes even more important. Teams are always looking to add grip at Fontana, and one way they do that is by dropping the air pressures, particularly in the left-side tires.
“While we have made some updates to our constructions over the past several seasons, low air can still cause problems. Going low on air causes the sidewall of the tire to over-deflect early in a run and weaken its structure, creating a potential problem later. Secondly at Fontana, you have a track surface that wears tires heavily. The fall-off is around three seconds a lap over the course of a fuel run, so tire management will come into play all day.”
As on all NASCAR ovals greater than 1 mile in length, teams are required to run liners in all four tire positions at Auto Club. Air pressure in those inner liners should be 12-25 psi greater than that of the outer tire.
Here’s the tire info for this week:
Set limits: Cup: three sets for practice, one set for qualifying and 11 sets for race; Xfinity: eight sets for the event
Tire Codes: Left-side – D-4834; Right-side – D-4838
Tire Circumference: Left-side – 2,227 mm (87.68 in.); Right-side – 2,251 mm (88.62 in.)
Minimum Recommended Inflation: Left Front – 19 psi; Left Rear – 19 psi; Right Front – 45 psi; Right Rear – 42 psi