These are the 3.8" Canyon AT Tires for use on the Traxxas Summit Truck RTR FEATURES: Aggressive, angular lugs Soft foam insets let the rubber conform to surfaces for maximum grip INCLUDES: Two 3.8" Canyon AT Tires with Foam Inserts REQUIRES: Installation on the vehicle SPECS: Outer Diameter: 180mm (7") Inner Diameter: 95mm (3.7") Width: 101mm (4")