Evolution of the "Circuit des 24 Heures"
The 24 Hours circuit has evolved since the first 24 Hours of Le Mans in 1923, with changes that have been mostly to improve safety. A total of 14 different track layouts have been used during the 79 races. However, the overall layout remains identical to the original track. This year the circuit has been modified at Arnage.
The very first Grand Prix of the Automobile Club de France in 1906 was raced on a triangular circuit of 102.85km that stretched from Le Mans, eastward to Saint-Calais and La Ferte-Bernard, but for the first 24 hours in 1923 the ACO significantly shortened and relocated the route to bring it back to 17.262 kilometers with a loop into the southern suburbs of Le Mans with a hairpin at Pontlieue. For security reasons, the circuit's northern tip was shortened in 1928, reducing the course to 16.240 km. The tip was trimmed again two years later, reducing the length to 13.492 km. Although there have been subsequent changes over time, the 24 Hours circuit settled to a length of between 13 and 14 km.
The circuit then remained unchanged for over twenty years, until 1955 and the tragic accident which has caused many fatalities among spectators. Adjustments to the pit area were necessary, and the Dunlop curve was changed, shortening the circuit by 31 metres. The new facilities had enhanced safety, but the speeds reached in the late 60s, a result of the Ford-Ferrari duel, had never been higher. The decision was made to build a chicane (Ford chicane) before the pit straight, which lengthened the track by 8 metres. It was on this track that record the distance covered in 24 hours was set by Helmut Marko and Gijs Van Lennep in 1971, a record that stood until 2010.
A renovation of infrastructure was undertaken in the early 1970s. The old road via Maison Blanche (White House) was abandoned and a new portion of 3 km, which was created between Arnage and the Ford chicane, extending the circuit to 13.640 km. In 1979, the construction of the bypass south-east of Le Mans led to the modification of Tertre Rouge (13.626 km), and the appearance of a roundabout in 1986 modified Mulsanne corner (13.528).
The following year, it was the turn of the Dunlop curve to undergo a facelift at the request of the FIM (Federation Internationale de la Moto). The Mulsanne Straight was resurfaced and two chicanes were built in 1990 (13.600 km). The Dunlop curve was again reworked in 1997 for the same reasons (13.605 km).
The portion of the permanent circuit between the Dunlop curve and Tertre Rouge is enriched with a quick left-right at the request of motorcyclists in 2002. They are also behind the latest change of the curve Dunlop in 2006, the radius of which was tightened to reduce speeds. Despite the overhaul of the turn, the length of the track was not affected. The work was undertaken at the same time as the village modernization and expansion of the paddock.
The latest development dates back to 2007 with the opening of the angle of Tertre Rouge and expansion of the run-off zone, bringing the circuit to 13.629 km. With the development of the Arnage corner for safety reasons, the circuit will change again this year. With evolving standards, always towards greater safety, 24 Hours circuit will remain in an ongoing state of revision.
Dave Davies
Photo: LE MANS (SARTHE, FRANCE), CIRCUIT OF THE 24 HOURS, LE MANS 24 HOURS, APRIL 24TH 2011, TEST DAY.