The MGC was primarily fitted with 72-spoke wire wheels on 15-inch 5J rims, these were far more common than disc wheels, particularly on export cars. The standard finish was painted aluminium, with optional chrome plating available from the factory. Wire wheels are available today in painted, chrome, and bolt-on chrome specifications, covering both restoration to original specification and modern alternatives. The 72-spoke count is specific to the MGC and MGB 15-inch and 14-inch wheels respectively, they are a heavier-duty construction than the 60-spoke wheels found on earlier MG models.
Wire Wheel Identification, 15-Inch MGC Specification
All MGC wire wheels are 15-inch 5J rims, larger than the 14-inch rims used on the contemporary MGB. This is because the MGC's Girling 11-inch front brake discs require a larger wheel diameter for clearance, MGB 14-inch wheels cannot be fitted to the MGC for this reason. The 5J rim width was the standard fitment, providing the correct tyre bead seating for 165HR15 tyres. Wire wheels are centre-lock, secured to splined hubs by a single octagonal knock-off nut or two-eared spinner that is tightened by mallet.
The left-hand side of the car uses right-hand thread spinners (tightened clockwise), and the right-hand side uses left-hand thread (tightened anti-clockwise), this ensures that the rotation of the wheel tends to tighten rather than loosen the spinner during driving.
Wire Wheel Maintenance
Wire wheels should be inspected regularly for loose or broken spokes, and retrued by a specialist if the wheel develops a wobble or hop. A loose spoke is easily identified by running a screwdriver handle or similar tool around the spokes while the wheel is off the ground, a dull or rattling note indicates a loose spoke, while a tight spoke produces a clear ring. Loose spokes should be tightened promptly, as the load that the loose spoke is not carrying is redistributed to adjacent spokes, accelerating their fatigue and potentially causing a cascade of failures. Corrosion at the spoke nipples, where the spoke passes through the rim, is common on wheels that have not been regularly maintained, and corroded nipples can seize, making spoke adjustment impossible without specialist equipment.