Updated casing design improves lateral stability in corners compared with earlier Michelin trials tires. Compatible with low air-pressure settings; recommended pressures for trials use: 6 psi front. Redesigned bead area increases sidewall rigidity to reduce tire movement on rim, even at very low air pressure. Maximized Contact Patch casing for better grip on loose surfaces and when cornering. More flexible tread area for better grip on obstacles and rocks M-rated for speeds up to 81 mph.Trial X Light rear is more than a pound lighter than its predecessor, reducing unsprung weight, for improved suspension response and maneuverability. Compatible with low air-pressure settings; recommended pressures for trials use: 5 psi rear. Redesigned bead area increases sidewall rigidity to reduce tire movement on rim, even at very low air pressure. Maximized Contact Patch casing for better grip on loose surfaces and when cornering. More flexible tread area for better grip on obstacles and rocks M-rated for speeds up to 81 mph.