Endurance racing stands out from other kinds of motorsport in that it tests not only the stamina and skill of the driver, but the sustained durability and reliability of the vehicle. Whether it's for 24 hours at Le Mans, 12 hours at Sebring, 10 hours at Petit Le Mans or 1,000 kilometers (621 miles) in the European races, these events prove not only which driving team reins supreme, but also which car can go the distance.
It's no wonder that auto manufactures take such pride in boasting about their wins at the great endurance races. However, auto manufacturers do not hold a monopoly on endurance racing vehicles -- far from it. Independent groups, known in the racing world as "privateers," also field fleet fleets on the circuit.
Endurance races usually take place on closed tracks with closed wheel cars (unlike formula cars, which have open wheels -- that is, wheels outside of the car body). The typical event involves teams of two to four drivers attempting to cover a set distance the fastest or to go the farthest in a specified time. Over the course of the race, the drivers must make pit stops to fuel and service the car, as well as to switch drivers, who each drive a "stint" lasting around an hour to 90 minutes. Because of the tactical importance of these switches, stints can be highly variable in length. Some races limit the stint length for safety reasons.
Several classes of car compete for endurance prizes. Some classes are populated by prototypes built to specifications set out for that race. The Le Mans Series (LMS) and American Le Mans series (ALMS) alone use two classes of prototype closed-wheel car. The first class, called Le Mans Prototype 1 (LMP1), is famously manufactured by Audi, Peugeot and Aston Martin. LMP2 cars are smaller, lighter and less powerful, but have potentially better power-to-weight ratios. Porsche, Acura and Mazda are known for their LMP2 prototypes.
In addition, three classes of sports cars, including Corvettes, Vipers, Saleens, Aston Martins, Porsches, Ferraris and BMW GTs, also compete at LMS and ALMS events. Races can also be limited to "spec cars" (in which all racers drive the same make of car, with the same chassis and engine) or touring cars (vehicles based not high-performance sports cars, but rather road cars).
Even in races that run such great distances and last so long, drivers and vehicles often achieve victory by a narrow margin. Many a 24-hour race has come down in the end to which team made the fewest mistakes.
Now that we have the basics down, let's take a trip around the circuit.