More knob equals more contact where you need it, offering better grip and handling in intermediate to hard pack terrain Constructed with a lightweight 2 ply+ breaker ply casing providing both high stability and flexibility Improved rubber compound for balancing both performance as well as durability An optimized knob spacing offers an increased contact patch with the ground Optimized for shredding through hard-packed trails or race tracks Not for highway service (NHS).. TIRE VX40 90/90-21