NASCAR has added mandatory fines and other penalties for teams caught without five lug nuts on each wheel.
The move announced Monday comes less than a week after three-time series champion Tony Stewart urged NASCAR to take action. The series had stopped monitoring lug nuts during pit stops and some teams were using fewer than five, allowing them to send cars out faster in hopes of getting better position and a better finish.
NASCAR can only check for every lug nut before and after a race, but may call a car back to pit road during a race.
The series said a tire falling off in a Sprint Cup race due to "improper installation" would mean a minimum four-race suspension of the crew chief and other pit crew members involved. If lug nuts are found missing after a race, Cup teams face at least a $20,000 fine and a one-race suspension for the crew chief. The penalties are less for the Xfinity and Truck series, but still substantial for the lower-funded teams.
NASCAR said a "long-term solution" was in the works.
Stewart was fined $35,000 for his criticism and that fine stands.