Product Information: Developed and tested at the Grand National Cross Country Series, the SI's race-proven tire construction delivers excellent traction and maximum durability in soft/intermediate conditions. Maxxcross SI is a go-to tire for our GNCC and WORCS pros Anti-flex knob bridges on side lugs offer solid straight-line stability and enhance grip for aggressive cornering Race-proven rubber compound delivers excellent traction and durability in soft/intermediate conditions on the motocross track or off-road