Endurance racing (motorsport) these classes continued to embrace the endurance format. Multiple drivers per car was an early adaptation as the rigors of endurance racing quickly overcome the abilities of most racing drivers to compete solo, although solo attempts on 24 hour races like Le Mans would continue into the 1950s. The various endurance formats were appealing to manufacturers, not only as alternatives to the expense of Grand Prix racing, but also because of its increased relevance to road going models. In automobile endurance racing, three events have come to form a Triple Crown. They are considered three of the most challenging endurance
Endurance racing (motorsport) side, but the two were soon separated. The most notable motorcycle endurance race was the Bol d'Or, first run on the circuit of Vaujours, near Paris in 1922. Only one rider was permitted per bike and there was no stopping other than for refuelling. Motorcycle endurance racing began to expand after the second World War as new races began to emerge, among them the 24 Hour Race in Warsage, Belgium in 1951, the 24 Hours of Montjuïc in Barcelona in 1957, 24 hours in Monza, Italy in 1959, and the Thruxton 500 mile endurance race at Thruxton, Hampshire, England in