Each 797 wheel is attached to the axle using 47 nuts that are torqued to 2,300 lb·ft (3,118 N·m).[17] A size 55/80R63 radial tire was developed by Michelin in conjunction with Caterpillar specifically for the first generation 797.[18] The Caterpillar 797B and 797F run on the largest tire in the world, the 4.028 m (13.22 ft) tall, 5,300 kg (11,680 lb) Michelin 59/80R63 XDR.[19] Six tires are required per truck at a cost in 2009 of approximately USD $42,500 per tire.