|Posted by macmillersgarage on April 6, 2009 at 1:19 PM|
The following is a short piece I wrote for a tech forum. It is about wire wheels used on dirt track and Indy cars into the 50s, but, maybe, it will be of interest to some of the "technoids" here ........
WIRE WHEEL TECH
The next time you encounter a vintage racing car with wire wheels,
look at them with a little bit of respect.
Wire wheels are very interesting and there is a lot more to the way they work than most people think.
There were three brands of wheels that were common in US oval racing in the 20s, 30s, 40s and, even, into the 50s. The low buck option was the stock Ford, welded spoke wheels made by Kelsey-Hayes. These were a bolt on wheel..........Another brand that I have run across is the Buffalo wire wheel. They were used on 30s and 40s "big cars" They used real threaded spokes and appeared to be a quality wheel......... The "top of the line" wire wheels were the Dayton Wire Wheels made in Dayton, Ohio. This company is still in business. They were used on the Indy Cars in the 30s, 40s and into the 50s.
Most of the good wire wheels were built on the, Euro origin, Rudge-Whitworth metric splined hub. Why? I'm not sure, unless it was from the influence of the pre WW1 euro participation at Indy. It was always a mystery to me how the most basic part of the most American type of racing used a euro metric standard component....??? Even into the 50s, some of the first magnesium wheels were built to fit on the Rudge metric splined hubs.
Many of the Rudge hubs were made in the U.S. by American manufacturers under license from Rudge-Whitworth.
There was a lot of more dynamics in a wire wheel than most people realize.
Wire wheels have a radial, lateral and vertical spring rate and can, totally, change the handing and feel of the car depending on spoke count, length and tension.
Ted Horn used his wire wheels for suspension tuning by having wheels with different spoke tensions and/or lace patterns for different race tracks and track conditions.
With today's totally rigid wheels the lateral spring rate is done with different tire side wall construction and pressures.
In the early 20s, Tommy Milton, Harry Hartz and Ira Vail had Millers that were sponsored by DiSteel. DiSteel made steel disc wheels.
They used their sponsor's wheels during the Indy 500, but found the ride very harsh compared to the softer spring effect of the wire wheels.
Another interesting effect of the early solid disc wheels or wire wheels with aero wheel covers was that when the drivers turned the front wheels into a corner, the air would catch them, like a sail, and cause the car to oversteer into the corner. For that reason the more common setup was to use the disc wheels in the rear with the wire wheels in front.
The most common sizes of wire wheels were 15", 16", 18" and, even, 20" diameter.
I have noticed that there were hardly any migets that used wire wheels.... apparently, there was nothing available in that size (12"diam).
Some of the Euro brands of wire wheels that, probably, saw action in U.S, racing would have been Dunlop, Borranni and Campagnolo.....
I'm sure some of the other esteemed historians of this list can come up with more detailed information than I have and I welcome them to add to this and, also, correct any misconceptions that I may have
Generally, the more flexible the the wheel is in lateral, radial and vertical load, the softer and more forgiving the ride.
Better handling characteristics, such as acceleration, braking and steering, require a stiffer wheel construction.
factors effecting wire wheel dynamics and characteristics
radial angle of attachment
lateral angle of attachment
lace pattern- radial or cross lace