By the USAC Technical Update (TB2018-NAT001) dated January 1, 2018, digital tire bleeders are allowed for the 2018 season in USAC National Series events. The directive states that air many not be introduced to the tire however. Bleeders cannot be controlled remotely.
As of May 1, 2018, full containment seats are mandatory in all USAC National Series events. Beginning in 2019, all seats must meet SFI 39.2 specifications.
The Silver Crown Series maintained the same tire options for events as the 2017 season.
For the National Sprint Car Series, no suspension adjustments by the driver from the cockpit are permitted. Front axle tethers will be mandatory beginning on May 1, 2018.
Hoosier Tire will make 94/14.0 tires available in RD12 compound for 2018.
Any questions about the directive can be directed to the United States Auto Club at (317) 247-5151