The 10-hour Petit Le Mans was the final round of the IMSA WeatherTech Sportscar series, which saw the GTP prototype class contested by BMW, Acura, Porsche and Cadillac. The latter two also competed in the FIA World Endurance Championship, running dual programmes with the same teams, Porsche Penske Motorsport and Chip Ganassi Racing.
While Cadillac won the IMSA title, it was hardly clear cut. Each of the manufacturers had at least one car in contention for the titles going into the final race and, while that might look like a success for the Balance of Performance system, it was in fact a series of mishaps that led to this close-run conclusion.
Key among the challenges faced by the teams were learning their new cars, getting to grips with the hybrid technology and, above everything, switching on the new Michelin tyres without warming blankets. This latter point is nothing new in the series, but the LMDh cars are heavier than the previous-spec DPi cars, have less downforce and are highly sensitive to ride height changes. There are also reduced set-up tools available to the teams as the cars must run in a certain lift / drag performance window in all conditions, which has made setting up these sensitive cars rather more tricky than their predecessors.
Series supplier, Michelin, introduced the same tyre to the WEC and IMSA series this year, and also cut the allocation of tyres by 30 per cent for the top class, aiming to encourage double stinting for the prototypes during all endurance races. However, as the majority of cars were not designed when Michelin would normally be going through its development loops, the French manufacturer had to rely on educated guesswork for some of the tyre settings.
The LMDh cars are heavier than the older DPi versions, have less downforce and are highly sensitive to ride height changes
Each of the teams had new cars and new technology to learn at the start of the year. Much of the development and testing of the standard hybrid system, consisting
