A fuel cell stack includes a first sub-stack, a second sub-stack, and a third sub-stack disposed in the flow direction of an oxidizing gas. The force is increased as a function of a measured variable which can be the number of revolutions of a feed roller on which the gripping surface is defined. The second pulley is spaced apart from the first intermediate pulley to align with the driven pulley and accommodate the oversized tire. Each of the absorption chambers is connected to a respective one of the storage containers.