How IMSA GTD Works
New to IMSA GTD? Learn how the Sprint and Endurance formats work, how class points are scored, and how to follow the season from round one.
The IMSA GTD class runs within the WeatherTech SportsCar Championship alongside GTD Pro, GTP prototypes, and LMP2 on the same grid.
Five of the season's eleven rounds form the Michelin Endurance Cup, headlined by the Rolex 24 at Daytona and 12 Hours of Sebring. The remaining rounds are shorter sprint-format events at circuits across the USA and Canada.
In 2026, fourteen full-season entries compete across fourteen different teams, with additional Endurance Cup-only entries from Manthey Racing and others. The Pro-Am rule mandates at least one Bronze or Silver FIA-graded driver in every GTD car.
GTD cars run to GT3 technical regulations with additional IMSA data loggers and safety mandates.
Sprint rounds: Two hours and forty minutes, one to two pitstops for fuel and tyres. Full-season drivers only.
Michelin Endurance Cup events: Six-hour, twelve-hour, and twenty-four-hour races with mandatory driver changes and FIA-grade minimum driving time requirements.
The Pro-Am rule requires at least one Bronze or Silver-graded driver per GTD entry. A GTD Pro class — professional-only crews — runs simultaneously on the same grid. AM radio communication between driver and engineer is mandated throughout each race.