Cooper Discoverer CTS Touring Radial Tire - 235/60R18 107H Tire only Coupled Silica tread compound delivers superior wet traction without sacrificing tread wear. 5 rib all-season tread design provides excellent stability, traction and treadwear. Stepped circumferential grooves resist hydroplaning and provide added grip on loose surfaces. An optimized polymer matrix allows the compound to remain pliable at lower temperatures while contributing to lower rolling resistance which can increase gas mileage