USVTA Tire Rules
As of January 1, 2018, only the Protoform 10139-00 and 10140-00 tires will be allowed for official USVTA events (Scale Nationals, Southern Nationals, etc.).
The HPI tire supply has become scarce in most situations, and Protoform has stepped up with solid availability. Allowing both tires creates a "haves and Have - nots" problem if one tire works better.
For those racers who have HPI tires, tracks may allow you to use those tires at club racing events at their discretion after January 1. While this is acceptable to allow racers to maximize the money they have spent on tires, official USVTA events will not allow HPI tires after January 1.