Important: We strongly recommend that the chains be fitted to the tire prior to actual use to ensure proper fit. Tire sizes may vary because of age, manufacturer, tread or type. Shur Grip Z meets SAE Class “S” clearance requirements (15.00mm). Once the chains have been installed, drive a short distance. If you hear any contact of the chain to any vehicle part, remove chains immediately. Vehicle manufacturers’ determine the clearance requirements based on the original (OEM) tires provided with the vehicle.