Three distinct types of road wheel were fitted to MGA cars across the model's production run from 1955 to 1962, and identifying the correct type for the variant and chassis is fundamental to ordering not just the wheel itself but also the associated hubs, knock-ons, spinners and hub caps. The three types are the bolt-on steel disc wheel fitted as standard to pushrod cars, the Dunlop 48-spoke wire wheel available as an optional extra on pushrod cars, and the centre-lock Dunlop disc wheel fitted exclusively to Twin Cam and De Luxe models. Each type has its own production changes and variant-specific details, and each has implications for the hub, half-shaft and brake hardware carried elsewhere in the MGA specification.
Bolt-On Steel Disc Wheels, Pushrod Cars
The standard road wheel on pushrod MGAs (1500, 1600 and 1600 Mk II) was a bolt-on steel disc wheel made by Dunlop, size 4J x 15, with four-stud fixing and twelve round ventilation holes, painted aluminium. Two production-change points affect the wheel specification.
From 1500 car/chassis 52070, the wheels were strengthened and made more crack-resistant by a modification adjacent to the brake adjuster holes, without change to the part number. From 1500 car/chassis 63577, a lighter but stronger revised wheel was introduced with altered construction, the wheel centre gauge increased from 10 SWG to 9 SWG, the rim thickness decreased from 13 SWG to 14 SWG, and the ventilation holes became more oval in section. Weight reduced from almost 17 lbs to 15 lbs.
The later wheels also had increased curvature at the centre section to give sufficient clearance for the disc brake calipers on the 1600 and 1600 Mk II, and were used through to the end of production in 1962. These later wheels were factory-recommended as replacements for earlier cars. The disc wheels were fitted with plain hub caps lacking the MG badge, except possibly on some very early cars according to 1955 factory photographs and brochures. Two hub cap types were produced, chrome-plated 22 SWG EN2A mild steel, and 26 SWG EN60 stainless steel, identical in appearance but differing in material.
Chrome-plated Ace rimbellishers were available as an optional factory extra, but were discontinued at car/chassis 63576 and do not fit the later-type wheel introduced from chassis 63577.
Wire Wheels, Pushrod Cars
Dunlop 48-spoke wire wheels, size 4J x 15, with steel rims and centre-lock fixing, were available as optional equipment on pushrod MGAs. The wire wheel construction uses 16 long outer spokes and 32 short inner spokes. The wheels were painted aluminium, chrome-plated wire wheels do not appear to have been available as original factory equipment. The knock-ons that secure the wire wheel to the hub were changed twice during 1500 production.
The original type carried the MG badge at the centre, together with the wording "right (off) side" or "left (near) side" and "undo" with a directional arrow. At 1500 car/chassis 40857, the knock-ons were modified to a more curved section across the centre. At 1500 car/chassis 48730, the MG badge was deleted, giving a third pattern.
From October 1958, around 1500 car/chassis 57500, octagonal spinners were introduced on cars for the German market, and were subsequently also fitted for the Swiss market. Octagonal spinners never carried the MG badge. A 60-spoke wire wheel, size 4½ x 15, with either steel or aluminium rims, was listed as part of the MGA racing and competition equipment. This was not available as original factory-fitted equipment, but was supplied through the BMC competitions parts channel.
For modern fitment, MGOC Spares supplies the 5.5x15" silver wire wheel with a 185/65/15 tyre (part W002/820X4) as the current wire wheel offering, shared with the MGB and suitable for MGA fitment. The W002/820X4 requires the 60-degree 7/16 UNF chrome tapered wheel nut W630A when fitted to an MGA; sixteen W630A are required for a full set of four wheels, and are ordered separately from the wheel itself.
Centre-Lock Disc Wheels, Twin Cam and De Luxe
The Twin Cam and De Luxe use a centre-lock Dunlop disc wheel that is unique to these models and not interchangeable with any pushrod MGA item. The wheels feature 15 ventilation holes, steel construction, and peg drive to the hubs, distinct from the splined-hub centre-lock fixing used on pushrod wire wheels. Neither the wheel hubs nor the knock-ons of the Twin Cam and De Luxe are interchangeable with those of a pushrod MGA, and the Twin Cam knock-ons have a coarser thread than those found on pushrod cars. The Twin Cam knock-ons were modified at Twin Cam car/chassis 1826, with the material changing from steel to bronze.
Twin Cams supplied to the German market were fitted with octagonal spinners from Twin Cam car/chassis 708 in place of the standard knock-ons.