225 45 R18 Goodyear Efficient Grip ROF Tyres Runflat tyres The Efficient Grip RunOnFlat is Goodyear’s Grand Touring Summer tyre featuring temporary self-supporting run-flat mobility for a distance of 50 miles at up to 50 mph even after a puncture has allowed complete air pressure loss. Designed for Original Equipment use on many Audi BMW Infiniti Mercedes-Benz Mercedes-Maybach MINI and Rolls-Royce vehicles the Efficient Grip RunOnFlat is tuned to meet the requirements of some of the world s most prestigious vehicles. The Efficient Grip RunOnFlat utilizes optimized silica summer-only tread compound molded into an asymmetric design that is tuned to deliver a smooth quiet ride and responsive handling. The addition of silica in the tread compound provides enhanced wet traction while the four wide circumferential grooves evacuate water from beneath the contact patch to improve hydroplaning resistance. The internal construction of the Efficient Grip RunonFlat includes two wide steel belts with a spirally-wrapped polyamide reinforcement to add durability and high-speed capabilities. The tyre’s reinforced sidewalls are capable of temporarily supporting the weight of the vehicle even without any internal air pressure. The casing material and ply count differ from size to size based on the needs of each vehicle manufacturer but include single- or two-ply rayon cord or single-ply polyester cord.