Automakers looking to boost the gas mileage of their vehicles are increasingly reinventing the wheel. Low rolling resistance tires, once an oddity found only on a few hybrid vehicles, are beginning to appear as standard equipment on many cars.
The Detroit News explains, "Tires, by their elastic nature, absorb energy in a process called flexing. When the engine spins the wheel, the tire flexes and turns that motion into heat." That's lost energy that could be used to move the car forward. Tires built from stiffer materials, however, flex less. That means they convert the engine's energy into motion more efficiently.
Autoblog reports, "The high-pressure rubber can return fuel economy improvements of 1-2 mpg in most instances, giving automakers that use them a leg up on the competition when comparing EPA data." There are drawbacks to the tires. The Detroit News points out, "Stiffer tires don't absorb energy as well as conventional tires and can add a few feet to braking distance." With some larger vehicles, that can be a serious concern. Autoblog notes, "Consumer Reports gave the [Ford] Escape a lower rating because it had such poor stop times" with its low resistance tires.
Cost is another concern. According to Kicking Tires, "Michelin estimates that its low-rolling-resistance tires can save drivers 68 gallons of gas over a lifetime of regular use. At $4 per gallon, that's just over $270." But the Detroit News found that "A search for low rolling resistance tires for the Ford Escape hybrid ranged in price from $150 to $260 per tire -- higher than a conventional one." For many drivers, that $270 savings won't offset the additional cost of four tires.
We can recommend a few more cost-effective ways to reduce your gas consumption.
For automakers buying the tires by the thousands, however, the cost is less of a concern. And in an era when fuel efficiency is one of the most important considerations in many car buyers' decisions, a car that can boast a mileage rating one or two mpg above the competition has an important market advantage.