Michelin, Dunlop and Continental supplied tyres for the race. In the Grand Prix's one major technical innovation, Michelin introduced the "jante amovible": a detachable rim with a tyre already affixed, which could be quickly swapped onto the car in the event of a puncture. Unlike in the Gordon Bennett races, only the driver and his riding mechanic were allowed to work on the car during the race, hence carrying the detachable rims could save time and confer a large advantage. The conventional method of changing a tyre, which involved slicing off the old tyre with a knife, and forcing the new tyre onto the rim, generally took around fifteen minutes; replacing Michelin's rims took less than four. The FIATs each used a full set, while the Renaults and two of the Clément-Bayards used them on the rear wheels of their cars. As carrying each rim added to the weight of the car over conventional wheels and tyres, some teams—such as Itala and Panhard—could not carry them without exceeding the weight limit.