Cooper Discoverer H/T All-Season Tire - 235/75R15 105S Tire only Solid center rib improves steering response while reducing noise. Four wide, notched circumferential grooves resistance to hydroplaning, while improving snow and soft-surface traction. High density zigzag sipes enhance wet traction and winter performance on snow and ice while maintaining tread element rigidity. Semi-closed shoulder design (exclusive notched: shoulder rib) increases the shoulder contact patch area to provide long, even wear and increased cornering performance while also reducing noise.