Suppliers Helping to Spare the Spare

6 October 1998

Suppliers Helping to Spare the Spare PNGV suppliers are pumping up a new tire program that may help the American car companies and their federal partners develop technologies enabling the design of midsize "supercars" with up to 80 mpg, while giving customers the security and peace of mind of "run flat" tire technology.

Run flat tire technology enables drivers to continue operating their vehicles safely after losing the air in their tires, even at highway speeds for 50-150 miles.

"The new tires would provide customers the security of not having to stop on the side of the road to change the tire," said Dick Swiatek, a representative from the PNGV systems analysis and vehicle engineering technical teams. "Additionally, they decrease the curb weight of the vehicle by eliminating the spare tire/wheel, the jack, spare cover, etc., which contributes nearly 50 pounds to a vehicle's weight. This weight reduction would improve fuel economy and help lower vehicle emissions."

Furthermore, the approximately three cubic feet of space made available by eliminating the spare tire and wheel, the jack, and the cover would provide much-needed packaging space for PNGV advanced technology vehicles, which typically contain additional components such as power controllers, batteries and other components that gobble up luggage space. For all of these reasons, run flat tires are especially attractive for PNGV researchers.

However, the road to PNGV-compatible run flat tires has a few potholes that need to be fixed.

PNGV technical goals have stated that high-efficiency, low-rolling-resistance tires are necessary to meet the up-to-80-mpg fuel efficiency goal. However, some run flat tires pose a special dilemma for researchers because they have somewhat higher rolling resistance. Also, run flat tires weigh more than standard tires, thus decreasing overall vehicle efficiency. It remains to be seen whether the tradeoff in overall vehicle weight and space savings is worth the increase in rolling resistance.

Compounding the challenge, highly-efficient tires require high tire pressures, which can affect comfort, noise, stability, ride and handling. Furthermore, run flat tires are more costly. All of these issues must be addressed in order for efficient run flat tires to become viable PNGV technologies.

The solution to these dilemmas will come from suppliers who produce run flat tires for conventional vehicles. Two such companies are Goodyear Tire and Rubber Co. of Akron, Ohio, and Michelin of Greenville, S.C., both of which have different approaches to achieving the goals. Other suppliers may join the PNGV research efforts in the future.

In spite of the challenges, PNGV engineers remain excited about the program.

According to Swiatek, "This technology is an example of the many tradeoffs that must be evaluated by the vehicle manufacturers and component suppliers in bringing the PNGV supercar to market. The improved security and increased fuel efficiency must not compromise customer expectations of comfort, ride, noise, handling and cost."