Bridgestone Battlecross X40 Motorcycle Tire Bridgestone X40 Convex "Castle Block" (rear tire) is a raised block in the center of the lug for enhanced traction in acceleration and braking. Asymmetric Block Pattern (front tire) with optimized block placement achieves stable grip during braking and cornering Features The edges of the convex blocks catch the track surface and achieve high grip on a wide range of terrains Provides high contact pressure against the track surface to enhance traction Cooling fins (rear) improve heat dissipation for consistent performance over race distances Wider terrain applications and higher level of grip than previous M403/ M404 combination