NASCAR has changed its wet-weather procedures at approved ovals, giving teams responsibility for deciding when to move from wet-weather tires to slicks once racing is underway.
The change, announced September 16 for the Bristol race weekend, shifts a decision previously controlled by race officials. NASCAR still determines whether an event starts in wet-weather conditions.
If rain brings a caution after the start and officials judge the track damp, teams may choose which tire configuration to use. Pit stops under caution remain non-competitive when pit road is designated damp; green-flag stops remain competitive.
The distinction matters because a drying track creates different judgments about available grip. Crew chiefs now have more room to choose when the potential speed of slick tires outweighs the security of the wet-weather option.
The policy applies to designated wet-weather ovals, including Bristol, Iowa, New Hampshire, Phoenix, Martinsville, North Wilkesboro and Richmond. It brings the decision-making approach closer to the existing procedure on road and street courses.
Source: NASCAR’s official report on the procedure change, September 16, 2026.