The MGB left Abingdon on steel wheels as standard equipment throughout its production run, with wire wheels offered as a factory option and remaining one of the most distinctive and desirable specifications today. Until 1969, the standard wheel was a simple four-stud disc with 12 oval ventilation holes, painted Aluminium with a very plain bright hubcap bearing no logo or embossing. Ace Mercury full-width louvred aluminium wheel discs were offered as factory-fitted optional equipment from 1963 to 1965, featuring an octagonal centre piece with an embossed MG logo picked out in red, and were offered until 1967 or possibly 1969.
MGC Wheel Specification
The MGC uses a larger 15-inch wheel rather than the MGB's 14-inch fitment, in a 5J steel disc and 72-spoke wire format. The larger diameter was necessary to clear the 11-inch Girling brake discs, and the 5-inch width provided the correct tyre bead seating for the 165HR15 radials specified by the factory. Because the MGC's brakes and geometry are specific to the model, original equipment specification wheels are manufactured to the correct dimensional tolerances to ensure proper fitment to the hub, correct alignment with brake components, and correct clearance within the wheel arches. A wheel that does not meet the correct offset or width can cause brake clearance issues, tyre fouling, or altered steering geometry, so the MGC's wheels are not interchangeable with the MGB's.
Rostyle Wheels
Rostyle wheels replaced disc wheels from September 1969 on the GHN5 and GHD5 series, from car number 187170. These had a quartered design with four prominent dividing spokes and two rectangular ventilation holes in each quarter circle, painted a combination of silver and black with a small hubcap bearing a black and silver MG logo. Chrome-plated Rostyle wheels were also available, becoming available in the home market on 1972 models, and were discontinued in June 1976. The painted Rostyle wheel continued to end of production, with an altered paint finish on 1977 and later models.
An important distinction exists between the two Rostyle specifications. Late rubber bumper cars from September 1976 received a wider offset wheel to counteract the increased body roll from the raised ride height, resulting in a one-inch increase in track across the axle. The two wheels are not interchangeable. To identify which is fitted, remove the centre cap and lay the wheel face down, the wide offset late rubber bumper wheel lies flat, while the earlier narrow offset wheel rocks on its protruding centre.
Both specifications are available on a like-for-like exchange or customer's own unit reconditioning basis.
Wire Wheels
Wire wheels are available in the original 4.5x14-inch centre lock specification in painted and chrome finishes, and in uprated 5.5x14-inch and 72-spoke 5.5x15-inch specifications for owners wanting a wider rim and more contemporary tyre fitment. Centre-lock 60-spoke wire wheels were normally painted Aluminium, with chrome-plated wire wheels becoming generally available in October 1965 and continuing to be offered until June 1971. Stronger 70-spoke wire wheels were quoted as competition equipment.
In September 1976, wire wheels were modified for improved tyre clearance to the wheelarches, and were fitted to 208 of the 421 home market LE Roadsters in 1980. A bolt-on chrome 5.5x14-inch wire wheel is also available. All wire wheels supplied are of an improved tubeless design, eliminating the need for inner tubes and rim bands.
Limited Edition Wheels
The final type of MGB wheel, in cast alloy with five spokes in a pentastar design, was found on the Limited Edition Roadsters of 1979 to 1980, and was fitted to 213 of the Roadster LE models. It was also optional on non-LE home market cars in 1979 and 1980.