These Duratrax^® ASCEND front and rear tires are Class 1 (4.19" outer diameter) size for maximum scale appearance, with a 1.9" inner tire/outer wheel diameter. Made from super-soft C3 compound rubber with an aggressive tread that bites into loose or muddy surfaces, these tires provide exceptional gripping power for climbing over slippery rocks and getting past the toughest obstacles. Sold in pairs with foam inserts included.