200TW as per SCCA® National Solo® Rules 2020 Sec 13.3 or with 2021 updates.
Fender cutting, flaring and non-standard wheel sizes are allowed.
Tires are permitted to be changed at any time. Multiple sets permitted.
No active, powered tire warmers.
2021 Update :
The Kumho ECSTA V720 ACR is no longer permitted.