DETROIT (Mar. 6, 2000)—High-mileage prototypes from DaimlerChrysler A.G., Ford Motor Co. and General Motors Corp. unveiled recently rely in part on experimental high-pressure, low-rolling-resistance tires from Goodyear and Michelin to attain their 80-mpg targets.
The vehicles and tires have been developed over the past several years as part of the government-sponsored Partnership for a New Generation of Vehicles. The partnership began in 1993 with the goal of developing an extremely fuel-efficient four-door sedan.
The vehicles in question, the Dodge ESX3, Ford Prodigy and GM Precept hybrid diesel-electric hybrids, share the 80-mpg fuel economy, but the prototypes take radically different approaches to achieve their target.
For GM´s futuristic looking Precept, Michelin tweaked its Proxima range of rolling resistance optimized tires, delivering a light-weight version that offers offers a 10-percent reduction in rolling resistance vs. its previous best, which was seen on GM´s EV1 electric vehicle.
The weight and rolling resistance advantages did not come without compromises, however. The Proxima RR is designed to run at 50 psi and treadlife is estimated at about 15,000 miles; this latter figure is double that of earlier Proxima prototypes, a spokesman said.
Neither Michelin´s Proxima nor the Goodyear tire on the Prodigy offer run-flat capability.
Instead, GM offers a low-tire pressure warning system and the ability to inflate the tires using an on-board compressor that normally keeps the vehicle´s air springs properly inflated.
Michelin claims four P175/60R16 85T Extra Load Proxima RR tires and specially designed aluminum wheels from Hayes Lemmerz International Inc. weigh 45 percent less than a set of conventional tires and wheels.
The Dodge ESX3, on the other hand, uses Michelin´s PAX tire/wheel system, taking advantage of the system´s run-flat capability to eliminate the spare tire.
At the moment, cost is no object. GM, which admitted to spending $50 million on the program, says it has not determined the price tag of a mass-produced Precept. Likewise, Ford says it is too early to say what a Prodigy will cost in production.
Ford spent $58 million developing a similar car for the Department of Energy, which kicked in the same amount for the 50-50 contract.
Aaron Robinson, Crain News Service, contributed to this article.