Seeing a Lexus with its rear tires steeply cambered by an overladen trunk, John Scott, a Wisconsin car enthusiast, had a brilliant idea. Now his concept for negatively cambered tires may literally reinvent the wheel.
Scott's idea — he calls it the Camber Tire, which he submitted for patent approval in 1998 and which was approved in 1999 — is a tire built with an outer sidewall that's slightly taller than the inside sidewall. That results in a continuing decrease in the diameter across the tread surface and allows for compensation for a negatively cambered alignment setting to the wheel. When mounted on a vehicle with independent negatively cambered suspension or negatively cambered non-driven axles, his research indicates that the Camber Tire can deliver substantially improved handling, ride quality, tread wear and fuel economy.
Better yet, it provides all these benefits for cars with independent suspension or non-driven solid axles with no additional add-on equipment — just a new set of tires and an alignment including properly setting the suspension camber.
Scott's physics look sound. We all know that standard tires aren't square to the road when a car's body leans into turns. A negatively cambered tire's shape allows it to maintain contact on those curves.
The phenomenon of negative camber is something racers have used for a long time to achieve higher cornering speeds. Even NASCAR drivers — despite knowing how we feel about NASCAR, we're willing to give them begrudging respect on this point — use the concept on oval tracks (where every turn is to the left). Teams will angle the right side tires in at the top and the left side tires out at the top to give maximum surface contact to all four tires in the turns.
But the tires aren't just for the track. Automobile's Don Sherman, wrote for the New York Times that he drove a Lancer GSR equipped with Scott's tires and found the CamberTire-equipped Mitsubishi
"demonstrated shorter stopping distances, higher cornering speeds and a markedly improved ride. The tires' breakaway at the ragged edge of adhesion was more progressive and predictable than the Mitsubishi's original-equipment Yokohama radials."
Here's a detailed look at the results of Automobile's tests:
That's all well and good, but there are some problem with altered camber tires. One issue racers have had with futzing with the camber is increased tread wear on patches of the tire with higher contact time with the road. Scott's Camber Tire beats the problem because its tread runs flat. He claims his prototype, in high-mileage tests, are able to maintain normal tire tread life because of that design
So, are Scott's tires the future? He's betting on it — and positive reaction from outlets like Automobile and even car guys like Jay Leno, can't hurt. Although his claim to have "reinvented the wheel" may be a bit of hyperbole, he did recently receive passing grades from the Department of Transportation (DOT) for durability and speed ratings. Scott's next step is to take the concept from niche performance tires — where he's currently focusing his efforts — into more conventional sizes. If he succeeds in bringing this straight-from-the-track tire technology to the masses then maybe he really has "reinvented the wheel."