From 1972 there were two different Pirelli Cinturato radial tyre sizes factory-fitted to new cars, depending on whether the car was a roadster,(155/80x14) or a GT,(165/80x14).The original tyres for the majority of MG B's were 165HR14 Pirelli Cinturato. With the 1974.5 arrival of the rubber bumper cars the factory-fitted tyre size was simplified to 165/80x14 for all cars, irrespective of whether the car was a roadster or a GT, and also irrespective of the wheel type (wire or RoStyle). Later on during the rubber bumper production period, alloy wheels were introduced on several different limited edition models - with the final 1,000 LE models being the last cars to leave the factory with alloy wheels. The factory built V8s were fitted with full profile 175HR14 tyres.