Note that there are two different parts for MGA spare wheel clamps.

H7336 Clamp is the black part in the pictures above and to the right. It is used for all 1500 roadster, 1500 Coupe, and 1600 roadster. These cars have the spare wheel pushed forward through the apperture in the rear bulkhead to stop partly above the battery cover. The tire hold-down clamp with large wing nut is then located to right of center in the boot space. This more common clamp is 8-inches long with a welded heal plate and round hole for the securing stud.

The spare wheel clamp for the MGA 1600 Coupe (the rusty one in the pictures bove) is slightly shorter than the one for the roadster, has a slotted hole and no heal plate.The MGA1600 Coupe part can be made from the more common part by cutting off the tail and relocating the hole (weld and cut), or elongating the hole upward.

The standard roadster (and 1500 Coupe) spare wheel clamp overall length is 8-inches. The hole is 1-3/8 inches from the tail end. The wing nut and threaded stud have 7/16-20-UNF thread. A road wheel lug nut will screw onto the stud.

Felt tire pads I bought from Moss Motors are 4-1/4" x 1-3/4" x 3/4" (2-pieces per car). No reason to believe they are wrong (yet). Apparently the original position is left to right just forward of the step in the boot floor, as shown on a prior page. Last time I installed new boot carpet I put the pads front to back on top of the ridges in the lower floor, and they seem to work okay there as well. This may even work better if you are stowing a 165-80-15 size tire.

With restoration work on my car I found that the diamond shape reinforcement plate under the boot floor was badly rusted where it was never painted between the layers of sheet metal. The boot floor itself was not significantly rusted, so I ground away the entire plate, For a replacement I installed a rectangular plate and soldered it to the boot floor, so no more gap between the layers and no more rust.

There are two pieces of sheet bent to form a "U" shape bracket in the middle to hold the pivot pin. These are spot welded through the boot floor to a stiffener plate underneath. A split pin passes through one of the brackets (they both have the hole) to secure the pivot pin. The pin secures an eye bolt that the clamp fits onto, which is in turn secured by a wing nut. The welded heal plate of the clamp sits directly on the boot floor.
 

Click for larger printable drawing in PDF format.
Print on ANSI B-size paper (17x11 inches) for full scale.
The 8-inch long part with turned up heal is for all roadsters and the 1500 Coupe.
The 1600 Coupe uses the shorter clamp without turned up heal.

Find more information on the 1600 Coupe spare wheel stowage in article CP-130

Or you can buy one from a Morris Minor (for cheap), and make short work of modifying that to work for MGA. See below. www.morrisminorspares.com
This tip compliments of John Hopwood


Tire clamp from Morris Minor, above and below.

On January 10, 2024, James T in York, UK wrote:
"I've obtained a Morris Minor Spare wheel clamp from Ebay for 6 (the new MGA equivalent is 60!). I have attempted to modify it into an MGA one. ... The description says 8" long" (for all roadsters and the 1500 Coupe). It will be shorter for the 1600 Coupe.

Good going, James. You make that look easy.