The science is simple—the air pressure in a tire is what carries the load, explained John Ramaika, regional fleet manager at Double Coin. Therefore, an underinflated tire requires more energy, meaning more fuel to roll. “The simplest and most neglected maintenance item which will impact tire performance and fuel economy is proper inflation,” he said.
The math is simple as well—there is a rule of thumb that 10% underinflation will cost about 1% in fuel economy, related Jim Garrett, long haul product category manager at Michelin North America. “Tires are designed for a specific amount of deformation for traction and stability and underinflated tires have more deformation,” he said. “The energy used to deform the tire comes from somewhere– ultimately it comes from the fuel tank.”
It’s easy to see how effective tire pressure management can help lower fuel costs.
“Tire maintenance and good policies and procedures contribute greatly to fuel economy because proper air pressure allows tires to perform at their maximum design levels,” said Tom Clauer, Yokohama Tire’s senior manager of commercial product planning. “Air pressure is the single most important component of any fleet maintenance practice as underinflated tires have a direct correlation to increased fuel consumption.
“Every fleet should set, maintain and enforce a strict policy concerning air pressure and it should be checked cold and daily,” Clauer added. “Drivers are the point of the spear for this and each time that equipment is in the shop for any service or maintenance, air pressure should be checked and adjusted. They should also take note of any irregular wear, which is usually an indication of a deeper issue, including the possibility of improper air pressure.”
Greg Kidd, application engineer at Bridgestone Americas Tire Operations, U.S. and Canada, said the manufacturer encourages drivers and fleet managers to be proactive about tire management.
“As a routine part of a pre-trip inspection, fleets should check all tire inflation pressures,” Kidd advised. “During normal operating conditions, tire inflation pressure can increase 15% to 20%. Therefore, it is recommended to evaluate tire pressures before driving begins when the tire is cold to ensure a more accurate pressure check. Bridgestone also recommends replacing the valve stem seal, core and steel threaded flow-through cap every time a tire is mounted.
“There is no significant difference in proper maintenance practices between the steer, drive and trailer tires,” Kidd continued. “ However, it is important to keep the tractor and the trailer axles aligned. That will ensure the tires are rolling straight down the road, which will maximize tire life as well as fuel efficiency.”
Michelin’s Jim Garrett said fleets should invest in new valve stems every time a tire is replaced, digital tire gauges for maintenance personnel, pressure stickers on the vehicle for each wheel position, and driver and maintenance personnel training, which the company offers on request.
“Training is also available through your trucking association, your local tire dealer and suppliers of any specialty equipment you might purchase,” Garrett added. “We also recommend becoming familiar with the service manual provided by the tire manufacturer.”
At Yokohama, according to Tom Clauer, classroom training can be accessed through associations and onsite training can be conducted by a tire manufacturer representative and/or engineering staff. The company also offers a commercial video training series.
ATA’s Technology and Maintenance Council is an excellent resource for fleets, noted John Ramaika at Double Coin. For example, he pointed to the TMC Radial Tire Conditions Analysis Guide for a comprehensive review of tire conditions covering probable causes and recommended actions.
Bridgestone’s Greg Kidd went on to point out that there are several options available for tire maintenance training, including on-site courses for fleets or sessions at the Bridgestone Texas Proving Grounds facility. TMC, he added, offers manuals such as Tire and Wheel Maintenance Basics for Drivers.
“While it would be difficult to quantify exact fuel savings from proper inspection and service procedures,” Kidd said, “one of the most effective ways to accomplish this is by working closely with a tire manufacturer to create a comprehensive tire management program.”
“Many of today’s trucks have sophisticated on-board monitoring systems that can be used to measure fuel economy,” said Jim Garrett at Michelin. “The data can provide an understanding of variables such as routes and drivers and can take time to collect, but many fleets are getting good at this and clearly recognize the quick payback in improved tire maintenance.”