Optional For Cobras American Racing Wheels

[Dan Case]

I responded to a wheel thread in another forum. I thought a version might be interesting to some folks in the Originality Forum.



Original 1960s wheels wise, American Racing published this advertisement. I have only seen it in old magazines twice. The wheels were made of a cast magnesium alloy.



Shelby American wise three versions are known, two “spline drive” versions used on works prepared street and race cars and one “pin drive” version was made for Ken Miles to use on CSX2431. Legend says that only two sets of pin drive wheels were made for Ken’s use, he used one set and they cracked because there just wasn’t enough strength around the pin holes, and the second set Ken didn’t use is said to have been obtained years later by a privateer Cobra racer.

Shelby American offered two similar “spline drive” mounting system design versions of these wheels for production street and race Cobras. They were a popular option. They were made with offsets appropriate for Cobras, clearance for their disc brake calipers, and extremely important clearance for steering arms/tie rod ends; both styles were sold on new cars. Both styles were offered in ½” width increments between at least 15X6 and 15X8.5 for Cobras. (American Racing offered 15X6.5 and up in their speed shop catalogs.) The 15X6 front wheels appear to be unique to Cobras and cleared the steering arms and their tie rod ends. (Most magnesium race wheels Shelby used on the front of Cobras required steering/steering arm modifications to get tie rod ends away from wheels.) A fairly common practice was to use 15X6 wheels in front and 15X7 wheels in the rear. If care was taken choosing tire sizes the owner might not have to enlarge the rear fenders for clearance.

The first version had a hidden splined steel adapter fixed to the wheel central hub with bolts threaded into blind holes in the magnesium. These wheels seemed to do okay with street and road racing use but had a problem develop during drag racing. People that have experienced the trouble first hand tell me that the threaded holes in the magnesium wallow out on rear wheels if used with drag racing. The holes enlarge, the adapters get loose, and the wheels get loose. The second design, often called the “drag wheel” design, and is so described in some old SAI parts lists, “bolt through” style adapter mounting. Now large bolts pass through the webs of the central wheel hub and magnesium wheel type lug nuts and washers clamp the wheel hub to fix the adapter in place. The second works Dragon Snake used them.

Front side of “road race” style 15X8.5 wheel.


Back side of “road race” style 15X8.5 wheel.


Front side of the “drag” race style 15X6 front wheel.


Back side of “drag” race style 15X6 front wheel.


I will mention that the American Racing Equipment spline drive magnesium wheels are not exactly light weight. An all steel 15X6 70 spoke (center laced) Dunlop painted wire wheel for a Cobra weighs in at an average of 23 pounds. The 15X6 drag style American Racing / Cobra wheel averages a little over 18 pounds I believe. The 15X6.5 six spoke Halibrand made pin drive wheels I weighed were around about 13-14 pounds if my memory is correct.

Other notes, early castings have hollow spokes and later ones have an extra rib added inside the rear of spokes.

For a while there was a vendor taking the modern aluminum American recreations of the curved spoke wheels being sold commercially and modifying them for Cobras. The wheels I looked at had been reworked by filling the standard bolt on lug holes, metal finishing to cosmetically hide that work had been done, the wheel remachined to used Cobra splined adapters, and Cobra style adapters added. Since the 1970s one shop has adapted not only American Racing five spoke wheels of several designs to original Cobras but several other brands of similar looking wheels.