Ever since racers discovered the quarter-turn fasteners invented by William Dzus and often used in aircraft panels, rodders who wanted convenience in attaching hood sides and other panels on their hot rods fell in love with them. They were cool and had that no-nonsense, go-fast connotation. Likewise, when attending dry lakes and Bonneville meets, guys with street rides were equally captivated with the spun-aluminum wheel covers produced by the late Dean Moon starting around 1950. Ever since, Moon discs have been a very popular choice of wheel treatment for rods with a traditional style. The racer look is achieved at considerably less expense than a set of four magnesium Halibrands.
Moon discs (there are other companies making aluminum disc wheel covers, but Moons are the defacto standard) appeal to a surprisingly wide audience. When you park somewhere, the number of people who comment on the Moons, especially people outside the hot rod community, will far outweigh the interest generated by billet wheels that cost 10 times more than those classic aluminum circles with the "sun ray" finish.
A complete setup for installing...
A complete setup for installing discs to steel wheels is available from Moooneyes with a deposit on the tool. Bonneville racer Harry Hoffman has his own tooling, the main item being a setup disc that has three equally spaced notches (Hoffman's 15-incher seen here) and dimpled holes for the buttons.
So what's the problem with Moon discs? It's a question of aesthetics in mounting them. Whether we're building a low-dollar traditional rod or a high-ender, most of us rodders feel bound by certain accepted fashion principles, written down a thousand years ago on two finned-aluminum tablets found in the desert around Muroc Dry Lake. With Moon discs, it's considered bad form to punch a hole in the discs for the tire valve stems to stick through; it interrupts the flow of the swirling finish. We must mention that Mooneyes still makes Moon discs with a ring of "snap on" clips on the back, and they offer a clean look when installed, but taking them on and off to check your tires will eventually chip paint from your rims. This style is available in diameters from 12 inches and up.
So what do you do about checking your tire pressure? You attach the disc to your steel wheels with screws around the edges, but every time you check your tire pressure, you have to remove the screws from all four of your Moons, lay the Moons down carefully where they won't get scratched, then put all the screws back in when you're through checking the air in the skins. If you're like most of us, where you placed the screws on your disc may vary slightly from wheel to wheel and you have to mark your discs (left-front, right-rear, etc.) and also make orientation marks so each disc lines up with the right spot on its designated wheel.
The steel wheel is marked...
The steel wheel is marked off with bits of tape to indicate the desired button locations on the rim. You want to avoid welding a tab over the wheel's valve stem. Here Hoffman is measuring the length of the tab from the center of the hole on the disc to the spot on the rim that has been ground bare for welding.
Bill Dzus' design uses a slot...
Bill Dzus' design uses a slot in the fastener that follows a curved path. When you turn the fastener it climbs downward onto the spring until the spring stops in a slot and the fastener and the two panels being joined are cinched up.
Using a bandsaw, Hoffman trims...
Using a bandsaw, Hoffman trims the tab to length, leaving a little extra so the wheel end of the tab can be ground to a curve matching the rim. In the foreground is the 598-inch big-block Ford for his latest Bonneville machine, a rear-engineed Modified roadster.
Hoffman holds down the center...
Hoffman holds down the center of the disc, while he tack-welds the tabs to the rim through the open cutouts in the disc. The tabs aren't fully welded until all three are tacked and you're certain the disc is centered on the wheel.
When the tab is the right...
When the tab is the right length (it should just meet the rim, but allow the disc to sit flat on the rim), the tab is secured to the mock-up disc with Cleco fasteners. There are various lengths of buttons, several spring depths, and mounting tabs are available in several lengths. We'll be using short tabs and the standard "500" buttons (0.500-inch long).
A master at TIG welding for...
A master at TIG welding for over 30 years, Harry made short work of finish-welding the three tabs to the wheel. You could also use MIG or a torch to do this.