Once you’ve made the investment in low-rolling –resistance tires, it would be a shame to negate the fuel economy benefits by letting the tire pressure slip. Testing done recently by Pressure systems International, manufacturers of the Meritor Tire Inflation System by PSI, show that a 20-psi drop in tire pressure can increase fuel consumption by about 2 percent per wheel position.
“What we saw in the lab test indicates that lowering rolling resistance does improve fuel economy,” says Al Cohn, director of new market development and engineering support at PSI. “For line-haul operations, a god rule of thumb is each 10 percent improvement in lab wheel rolling resistance is roughly equal to 2 percent improvement in fuel economy in the real world.”
Other factors that contribute to increased rolling resistance, and thus an increase in fuel consumption, include payload weight, ambient and pavement temperature (the lower the better), pavement surface conditions (the harder the better), and vehicle speed.
