On the Road

When it comes to tires, things are changing fast and furiously. Here's a look at some of the legislation and design trends that could affect your fleet in the not-so-distant future.

By 2003, your trucks and trailers could be equipped with a new piece of technology known as a tire-pressure warning system. The purpose of this device is to warn drivers when their tires are “significantly” under-inflated. Right now, however, we don't know how it will work or how much you'll have to pay for it — and pay for it you will.

Last fall, Congress passed the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act, which mandates new safety standards for tires, as well as more stringent reporting of safety-related tire defects. This legislation also contains a section that requires air pressure warning devices on all medium- and heavy-duty truck tires, as well as trailers.

During a recent TMC presentation, Guy Walenga, engineering manager for Bridgestone/Firestone Tire Sales, explained that Section 13 of the TREAD Act requires NHTSA to have a tire-pressure warning system rule in effect two years after it begins the rulemaking process.

Congress is pushing to have the process start this year, perhaps as early as June or July, which means that by the summer of 2003 fleets may have to comply. As Walenga points out, they'd have to have something in place and functioning that doesn't even exist today.

Part of the problem is that TREAD doesn't define “significant under-inflation.” Truck tire makers consider a unit under-inflated when its air pressure is 20% below the recommended level. Will the government agree? No one knows.

And that's not all that's up in the air. Will the system use gauges, lights or buzzers to warn drivers? Will the trailer's warning system be connected to the tractor, hard-wired through the seven-pin connector, or will it use radio signals beamed from special tags placed in the tires?

Fortunately for trucking, said Walenga, NHTSA wants more time to look for cost-effective options. The concept of tire pressure warning systems has been around for awhile, he pointed out, and their use as standard equipment has a lot of support from trucking. But no one thinks it's a good idea to push them out the door because the government thinks it's time.

Larry Strawhorn, vp-engineering for the American Trucking Assns., added that he doesn't expect the rulemaking process to be accomplished in two years. “The starting gun has been fired, but we're a long, long way from the checkered flag.”

Michelin North America thinks the future of the over-the-road linehaul business rides on a single tire, rather than on the dual tire setup common to trailer axles and rear tractor axles.

According to Michael Hurley, market analyst for Michelin's longhaul tire products, most tire failures on tractor-trailers happen on the inner dual tire — the one most drivers and technicians find hard to check. Also, the axle support required for dual tires can mask under-inflation in some cases.

These issues are what drew Michelin to the concept of a linehaul single. Drivers only need to check four rear-axle tractor tires instead of eight. In addition, testing by Michelin showed that fuel efficiency improved by 5% when fleets used four tires rather than eight on trailer axles and rear tractor axles. (See Nuts & Bolts item on page 59 for more information on Michelin's X-One.)

Putting microchips in truck tires isn't a new concept; in fact, tire makers have been experimenting with them since the late 1980s. Yet, according to Al Cohn, manager of technology and training for Goodyear Tire & Rubber Co., although the cost of this technology is no longer sky-high, it is still not affordable for on-highway fleets.

“We actually made this technology commercially available for earthmover tires last October,” Cohn says, “but it remains very expensive. We've evaluated its potential for the over-the-road truck market for some time; it does work, but the issues of cost and durability are still concerns.”

For its 40.00R57 off-road tires — designed for 240-ton mining trucks — Goodyear attaches what it calls an “intelligent” transponder to the inner liner of all six of the vehicle's tires. The 3-in.-diameter, 1.3-in.-thick sensor measures tire cavity temperature every three minutes and transmits the data to a receiver in the truck cab. Sensors can be programmed with tire identification and truck numbers, enabling operators to see which tires are getting hot and adjust routes accordingly.

The same type of system is being contemplated for truck tires, says Cohn. But when it comes to these chips, tires on trucks bring more complications. “For a $50,000 off-road tire, you can afford $1,000 worth of sensor technology to help maximize your investment,” he says. “For an OTR truck tire, however, our research shows that fleets would be willing to pay $3 to $4 for a chip. But materials alone cost more than double that, not to mention labor and design costs.”

Durability is another issue. “A truck tire can be retreaded four or five times in its lifetime. Can a tire chip survive the high-heat retreading process? Can it also survive the high load and wear and tear of the operating environment?”

Goodyear and other tire makers continue to work on tire chip technology because of its huge tire management benefits. “If we can get cost and durability issues solved, this product would be a big winner for fleets — especially for checking tire air pressure,” Cohn says. He pointed out that while it takes about 20-25 minutes to check the air pressure on all 18 tires of a typical tractor-trailer, tire chips could reduce this task to about 5 seconds.

The extensive information provided by tire sensors can allow fleets to make better business decisions. “You'd have an easy and fast way to identify your tires, check their temperature and casing wear, and even record revolutions per mile,” he says. “From a tire management perspective, that data is very valuable.”

While chips for truck tires may be relegated to the research lab for now, Cohn thinks that could change quickly. “Microchips are like personal computers: Every six months, a new one comes out that is twice as fast and costs half as much,” he explains. “At some point soon, we'll get the technology we need to make truck-tire chips cost-effective and reliable.”

For more information on all commercial tire suppliers, go to “Tire Resources” at www.fleetowner.com.