PROPER AIR PRESSURE
Under-inflated tires are one of the biggest causes of excess fuel usage in the world. The American Automobile Agency has stated that operating a vehicle with underinflated tires can result in a 25-percent reduction in fuel economy. Ouch.
TIRE CONSTRUCTION
The lower the rolling resistance, the less effort from your engine, the better the gas mileage. This is why passenger tires offer better gas mileage and longer tread life than SUV/Light Truck tires and winter tires, whose heavier tread patterns are designed with maximum traction in mind.