Carmakers expand fuel-saving tires to mainstream models

Cars like Honda's Civic Hybrid and Toyota's Prius have long been known to use harder-than-normal tires as part of the overall package to improve fuel efficiency. Now U.S. carmakers, especially those in Detroit, are looking to the simple technology to improve fuel economy performance of a wide range of vehicles in the face of consumer demand and impending CAFE standards.

Both General Motors and Ford Motor Co. will be employing the low rolling resistance tires in 2009 model cars. The entire Ford compact SUV line, for example, will be using the technology, reports The Detroit News. Expected improvements are in the 1-2mpg range in highway driving, depending on the vehicle and the previously specified factory tire. The gains aren't enormous, but as Scott Miller, GM's vehicle performance manager for full-size hybrid trucks said, "Every bit helps."

The low-resistance tires work by flexing less as they roll, meaning less energy is absorbed by the tire's carcass as heat and more is transmitted directly to the road as forward motion. Downsides of the tires include higher cost and somewhat reduced grip thanks in part to the different compound and in part to slightly higher tire pressures, though wet performance is claimed to still be 'solid'. GM doesn't recommend taking the tires offroad, however.