These are the 31mm D Compound Vintage Performance Tires from HPI. FEATURES: Must be used with 31mm Narrow Vintage Wheel Series Rubber construction D compound INCLUDES: Two Vintage Performance Tires Two foam inserts REQUIRES: Installation on wheels SPECS: Outer Diameter: 65mm (2.6") Inner Diameter: 41.75mm (1.6") Width: 26mm (1") lmm 01.26.10 ir/jxs