Any fleet manager with a spreadsheet can tell you that tires are important to the bottom line. Not only do they provide the requisite barrier between load and road, but they account for what's general...
Any fleet manager with a spreadsheet can tell you that tires are important to the bottom line. Not only do they provide the requisite barrier between load and road, but they account for what’s generally seen as the Number 3 operating cost behind fuel and employees.
Sometimes the understanding doesn’t go much deeper than that. Myths and misconceptions continue to direct purchasing habits and maintenance procedures; common mistakes lead to the point at which the rubber meets the road … and shreds into little bits.
Want to maximize the life of your tires and trim operating costs? Consider these key facts and tips we’ve assembled with the help of industry experts.
1. Retreading does not lead to ‘gators
One of the most effective ways to reduce overall tire expenses is to adopt a retreading program, yet some fleet managers continue to embrace the myth that any alligator – road debris in the form of a shredded tire – is a retread gone awry.
The debris itself can dispel the myth. Strands of wire sticking out of the rubber have come from a casing’s radial belts. You won’t find them in a tread.
“If they’re having problems with in-route tire failures, more than likely they have a problem with tire inflation,” says Don Schauer, Bandag’s manager of fleet communications.
If your fleet clings to the idea that retreads aren’t worthwhile, consider this: The casing on a $500 tire can be worth more than $100 on its own, says Michelin’s Ralph Beaveridge, and the retread could cost half as much as its brand-new counterpart. The resulting retread may not match the life of a new tire, “but you’ll certainly get much more than three-quarters of it,” he says.
2. Clubs don’t measure pressure. Gauges do.
Drivers may thump tire sidewalls to identify flats, but the practice won’t identify tires that have lost 20% of their air pressure, and that’s the point at which they should be pulled from service. “In my experience, 80 psi sounds pretty darn similar to 100 psi,” says Greg Cressman, deputy director of technical services at Yokohama Tires.
What’s the big deal? An under-inflated tire will be exposed to greater deflection (the flexing of the sidewalls), and will generate heat that can prematurely age the rubber, Bridgestone notes.
To compound matters, linehaul truck tires will lose 9% to 16% of their tread life if they’re underinflated by a mere 10%, according to the Technology and Maintenance Council of the American Trucking Associations.
The costs don’t end there. The same air loss will trim fuel efficiency by about 0.5%. That may not sound like much, but it can equate to more than $100 per truck every year.
The only accurate measurement of tire inflation is to put a gauge to a valve stem.
“It’s a time-consuming thing to do. It also tends to be lower on the scale of things that can be done on a PM schedule,” Cressman says, “but it pays the biggest dividends.”
3. Match dual wheels – and their tire pressures
Even if you’re ensuring tires are properly matched on dual wheel assemblies, your efforts are wasted if they aren’t inflated to the same level. That’s a common problem when you consider that inside tires are usually more neglected than their easy-to-reach counterparts, Cressman says. “The dual with the extra air is going to carry a disproportionate level of the load, and the other one is skipping along and [generating] irregular wear.”
4. Calibrate gauges every week
But keep in mind that a $20 gauge needs to be calibrated in the name of accuracy.
How far off can the reading be? “That depends how many times you drop it,” says Goodyear technical marketing manager Al Cohn, who recommends checking against a master gauge once a week.
5. Protect your valve stems
Valve stems can be jammed open by everything from yard debris to ice. One of the cheapest ways to protect them is to spec’ good valve caps, Bridgestone literature notes. “Quality metal valve caps are a must. Caps are the primary seal against valve leaks, and also keep dirt and water out of the mechanism.”
“Ultimately, the best air seal is given by a standard metal valve with a grommet that’s in good shape,” Cressman agrees. But he says an even better choice is a flow-through valve stem that offers easy access for an air gauge.
6. Never underestimate the personal touch
As important as equipment can be, one of the best indicators of irregular wear continues to be the human touch.
“Uneven or cupping or some type of alignment wear or toe in or toe out condition, you can feel that with your hands,” Cohn says. “I call it fingertip diagnostics.” If treads are rounding out on the outside edges of both steer tires, for example, the vehicle may be facing a toe-in situation.
7. Conduct alignment checks when installing tires
A set of steer tires can cost more than $800, and will tend to outpace the wear on a drive tire by a rate of two to one, so it makes sense to protect the investment by checking for alignment problems at the time they’re installed, Cressman says. At the very least, put vehicles on the alignment rack once a year.
8. Reconsider the value of a good tire tech
Tire technicians are often seen as the entry-level jobs at most maintenance facilities. The problem is, once they’re trained and truly understand tires, they move on to other disciplines. “You want to hire somebody who really has some tire knowledge, who cares about the tires and is going to do the job right,” Schauer says.
It’s particularly important to find experts that understand the wide proliferation of new tire designs, he adds, referring to the growth in application-specific treads since the mid-1990s. “You may be happy with the product you’re running now, but with the new application-specific products, you might see some dramatic improvement if you move to one of them.”
“One of the most common errors made today is that tractors or trailers are ordered and sold to customers with a tire that does not necessarily meet the customer’s needs,” warns Brian Riddell, regional fleet manager for Bridgestone-Firestone. That may reduce the cost of an initial order but the savings can evaporate when the tires are subjected to forces that cause irregular or premature wear.
9. Expand the size of your test fleets
The success of any tire evaluation effort is going to be measured by the size of your test fleet. The Technology and Maintenance Council (TMC) suggests that 30 types of any tire should be available at the end of the test.
You should also pay close attention to the standards that you’re measuring. Beaveridge suggests ranking the importance of various attributes when you’re comparing any tires. Start with a simple pass or fail based on traction needs. Then track costs by kilometer or any other measure used by your fleet.
Once you have a test fleet established, it’s important to remove as many variables as possible, says Matt Schnedler, Bandag’s product evaluation manager. Each tire should be exposed to a similar weight and a similar route, as well as similar engine torque.
If comparing tread life, put one brand of tires on the left front and right rear position, and the same size of the other brand in the opposite positions, he adds. Then do the reverse on the next truck. This eliminates variables associated with the driver.
If you’re looking to measure such things as fuel efficiency or reports about traction, however, the entire axle should be equipped with the same tire.
10. Let your tests run long enough …
Keep in mind that some tire treads include more than one rubber compound, each of which will scrub away at a different rate. “I wouldn’t even look at the data until they’re 50% worn to make projections [on when they would need to be pulled],” Schnedler says.
11. . . . but not too long
Some fleets will pull drive tires once treads reach 10/32, and move them to the trailer, Beaveridge says. Others will run them to a 4/32 depth before pulling the tires for retreading. In general, tires should be pulled well before their tread depths reach out-of-service limits if you want to protect casings.
“If you take it all the way down, you risk some stone drilling and punctures,” Cohn says.
12. Ask specific questions when comparing traction
Traction issues are probably the most difficult to measure because you’re limited to anecdotal feedback from drivers. But be sure to track as many aspects as possible to determine any differences. What were they carrying? What were weather conditions like?
13. Be honest about worst-case loads
When spec’ing tires, it’s also important to be honest about the heaviest weights the tires will need to carry, Cohn says. “You can’t have a tire that handles just 70% of your loads.”
Fleets also need to offer in-depth route information to their suppliers, Cressman adds. As application-specific tires become more refined, they’re also devoted to a narrower range of uses. Even if you’re traveling beyond a 300-km radius, premium steer tires may not be suitable because the equipment is devoted to an LTL operation that has multiple stops.
It’s simply a matter of giving your tires the attention they deserve.