Fleets Need Stricter Tire Maintenance Routines as Highway Conditions Worsen, Makers Say

This story appears in the June 30 print edition of Transport Topics.

With the federal and state governments hard-pressed to keep roadways in good shape, extra attention to tires during and between hauls is essential to maximizing their life span, manufacturers said.

Truck owners, carriers and their maintenance shops also need to emphasize that vigilance with their drivers, tire makers added.

Proper inflation, balance and alignment, mounting, cargo weight, load distribution and axle positioning are key considerations, they said, adding that an encounter with a pothole or a curb can cause serious, multifaceted damage.

“The potholes and damaged pavement may require you to remove tires more often so you do not have a damaged tire running next to a good tire, thereby risking losing both tires when the damaged one fails,” said John Hull, national sales manager for manufacturer Aeolus Tires USA. “Worse yet is to have that failure occur on the road where replacement can be costly and downtime becomes a factor. The driver needs to be vigilant in taking a close look at his tires every time he is out of the truck to catch potential problems.

“Also, with potholes there is always the potential for wheel and suspension damage including front-end alignment that can cost tire life if not inspected and repaired promptly. Frequent tire inspections will also detect wear characteristics that might cause you to consider a different type of tire,” Hull said.

He added, “Some basics never change with regard to maximizing tire life and safety; they just become even more critical when dealing with deteriorating roads and an aging infrastructure. Rule No. 1 is to look at your tires more often when operating on today’s roads.”

Robert Braswell, technical director of American Trucking Associations’ Technology & Maintenance Council, told Transport Topics that when a tire suddenly hits a road hazard or a pothole that damages it, that condition is called “an impact break and/or radial split.”

“An impact break is a break in the sidewall and/or tread (crown) through the casing, causing immediate air loss. This condition will usually deteriorate quickly to a run-flat appearance,” he said, adding that overinflation will aggravate the problem.

“A radial split is also the result of a severe impact,” Braswell said. “It’s a vertical break through the inner liner and perhaps the sidewall, occurring between two body ply cords, that does not break the cords. Radial splits in the inner liner usually produce a bubble or split in the sidewall but not always. External sidewall splits always result in a split in the inner liner.”

He added, “If it occurs, typically the tire must be scrapped.”

Braswell also said, “Fleet managers should review driving, vehicle operation and inflation maintenance procedures” when such incidents occur.

Life would be ideal if trucks could travel exclusively on major highways, said Todd England, executive vice president of Salt Lake City-based C.R. England, a refrigerated carrier that ranks No. 19 on the Transport Topics Top 100 list of the largest U.S. and Canadian for-hire carriers.

Highways are maintained better than are side roads and urban streets, England said. Tires suffer more damage from turning during city driving — “sidewalls hitting curbs, that sort of thing” — than during highway trips, he added.

Al Cohn, director of new market development and engineering support for Pressure Systems International, supported England’s observation.

Key factors in tire life include tire make and model, driver habits, road surface composition, road terrain, travel speed and load weight, Cohn said.

New drivers tend to be hardest on tires; their often abrupt braking and turning can speed tire wear by 35%, so driver training is important, he added.

On a 100-point scale for grading tire wear — where the higher the number, the more tire-friendly the road surface is — asphalt gets a rating of 100, concrete gets a 95, gravel 65 and dirt 50, Cohn said. Roads that are flat rate a 100, those that are “slightly hilly” get a 95, “hilly and slightly curvy” roads get a 75 and mountainous roads get a 50, he added.

The rating system also measures speed’s effect on tire wear.

Speed “generates heat. It is a tire’s worst enemy,” Cohn said, adding: The wear rating is 100 for a tire traveling 50 miles per hour, 85 for 60 mph, 75 for 70 mph and 60 for 80 mph.

Tire balance also can go out of whack on poorly maintained roads.

Roger Bertrand, business development manager at Counteract Balancing Beads Inc., which makes beads used to help maintain tire balance, pointed to the importance of understanding wheel-end and drive-line vibrations that could indicate that a tire is out of balance.

“Any tire on a vehicle can cause vibrations throughout the vehicle if out of balance. The speed at which the vibration occurs will determine if the vibration is caused by a wheel-end vibration or drive-line vibration,” he said. “Drive-line vibrations usually start at a lower speed and worsen with acceleration. Wheel-end vibrations, typically begin over 50 mph and subside 5 to 10 mph later. This range is dependent on the natural rebound frequency of the suspension, coupled with the tire’s diameter and the out-of-balance wheel assembly creating a resonance.”

Besides over-the-road risks, failure to educate personnel to tire-life issues can be costly, company representatives said.

“There is turnover in the tire shop. You’ve got to make sure you get that basic training down again,” said Guy Walenga, director of engineering for commercial products and technologies at Bridgestone Americas Tire Operations. “A $400 tire times 18 is going to have a very big impact on the bottom line.”

Walenga also said that even a sound roadway isn’t necessarily problem-free. Regional variations in materials and surface design affect tire wear. The crushed shells used in road surfacing in Florida are abrasive; Southern highways have a higher crown than those in the North. That higher crown causes “unique tire wear,” he said.

“To extend the life of tires, fleets should always have a good written maintenance policy in place to specify the maintenance practices they want followed,” said Paul Crehan, director of product marketing for Michelin Truck Tires. “This policy should be specific to their vehicles, equipment, geography, distance they travel, loads they carry, time on the road and other pertinent factors. It should also cover the specifics of new replacement tires entering their fleet as well as a retreading policy.

“Establish a training program for the operators to ensure they are properly trained,” he continued. “Training for those who handle tires is crucial. An untrained person can destroy good equipment without the proper training. In fact, [the U.S. Occupational Safety and Health Administration requires] anyone that touches a tire to have basic training. Several sources offer formal tire-handling training, including tire manufacturers such as Michelin, and the Tire Industry Association.”

Then there’s the inflation problem.

Walenga said improper inflation can deteriorate the casing to the point where a tire might not be retreadable. Optimum pressure varies with a tire’s size, and all tire makers can provide guidance charts, he said.

Overinflation is not necessarily harmful, Walenga and Hull said.

“Air leaks out of a tire, not in, so you want to err on the side of over-inflation,” Walenga said. “Most linehaul fleets run 85 to 95 psi [pounds per square inch] on drives. On your steer axle, there’s not a lot of room for error. There should be no more than a 5-psi variance between tires in dual (applications), because they must turn and go the same distance at the same time.”

“By running a tire constantly underinflated by 20%, its tread life will be reduced by 30%, while 40% underinflation will reduce the tire life by 50% — not to mention factors like irregular wear, higher thermal and mechanical fatigue of the casing, lower retreadability and even premature failure,” said William Estupinan, vice president of Technical Service for Giti Tire USA, which markets and sells GT Radial commercial tires in North America.

“Underinflated tires lead to increased flexing, increased heat buildup, faster wearing, increased fuel consumption — 10 psi = 1% mpg — poor feeling on the road [and] loss of traction in turns. Overinflated tires can also be an issue when encountering shoddy road conditions, including reduced shock absorption, suspension wear and vulnerability to cutting and impacts,” Estupinan said in an e-mail.

He added, “In addition to a proper air pressure maintenance program, periodic rotation also extends tire life by preventing, or at least reducing, irregular wear — [such as] camber, river wear, toe-in the front axle; heel and toe, step-down in the drive axle.”

For monitoring tire pressure, “I recommend dial-type gauges, sometimes described as a master gauge, as the most accurate type of gauge, but a large metal dual foot truck tire gauge is generally accurate enough for everyday use. It is important to check your metal gauge every few months against a ‘master gauge’ as it will over time get less accurate due to wear and tear,” he said.

Michelin’s Crehan said pressure readings should be taken while the tire is cold and the pressures adjusted to match the loads they are carrying. Load and inflation pressure charts should be checked to determine what that pressure should be, he said.

“With the onset of cold weather, tire pressures will drop and it is imperative to set the tire pressure prior to operating the vehicle at the onset of the trip while the tires are at ambient temperature. The ideal time to check tire pressures is during the pre-trip inspection prior to departure. Driving, even for a short distance, causes tires to heat up and pressure to increase,” he said.

“Pressure in the tire will change with changes in ambient temperature. It is a 10-2 ratio. For a change in ambient temperature of 10 degrees Fahrenheit the pressure will change 2 psi. This is really not enough for the driver to be concerned,” he said.

Vehicle alignment and in-wheel seating of tires also are extremely important, Walenga said. Axles should be perpendicular to a vehicle’s center line, he said, and tires should be seated concentrically.

“Always air it up in the safety cage, eyeball that the GG ring [cosmetic rings on the lower sidewall above the rim that provides a guide for checking concentric bead seating] is equidistant from the wheel rim, then turn it around and look at the other side for the same thing,” he said.

Walenga also said when mounting a tire, always put in a new valve core because a used core will never seal as well, he said, and make sure that valves on inner tires can be accessed through hand holes in the outer tires.

“Proper truck maintenance is also very important to the overall tire performance and wear of a tire,” said Cooper Tire & Rubber Co. in an e-mail.

Cooper said rotating tires as needed, regularly checking alignment and replacing worn suspension components can help prevent irregular tire wear.

Fleets also are working with manufacturers to find the right tire for their applications.

Dan Fogleman, spokesman for Tyson Foods Inc., based in Springdale, Arkansas, and ranked No 11 on the Transport Topics  list of the largest U.S. and Canadian private carriers, said, “We’ve been working with tire manufacturers and are actually seeing improved performance in recent months. . . . [T]he primary benefits are being derived from improved design.”

Double Coin Tires, Goodyear Commercial Truck Tires, Yokohama Tire Corp. and Pressure Pro declined to comment for this article.