Medium and light truck tires are more crucial to the North American vehicle industry than ever, according to two speakers at the Clemson Tire Industry Conference at Hilton Head.
New wide-base single truck tires, designed to replace tandem tires on tractor-trailers, carry the same loads as the traditional tandem arrangements on 85 to 87 percent of the tread width, according to Guy Walenga, engineering manager-commercial products at Bridgestone/Firestone.
These tires offer numerous benefits to commercial truck fleets, Mr. Walenga said at the March 20-22 conference. They are easy to retrofit on trucks with tandem wheels; offer easier tire pressure maintenance because there is only one valve per axle end and no inside dual position; and offer lower rolling resistance for better fuel economy, as well as reduced irregular wear and lower tire costs.
They meet the inch width limitation laws in every state, Mr. Walenga said, and also allow the use of new compounds, belt packages and bead designs for greater performance, durability and retreadability.
Nevertheless, both state legislators and long-haul truckers are leery of the new product, according to Mr. Walenga. The former group thinks erroneously that wide-base tires are more damaging to roads than tandem tires, with the upshot that many states have banned wide-base tires.
``Wide-base tires make up a little less than 5 percent of the market,'' he said. ``Sixty to 65 percent of them are flotation or construction tires, with the other 40 percent in regional or line-haul applications, mostly tanker fleets. Yet wide-base tires are blamed for every rut in the road.''
Driver perception also has hampered acceptance of wide-base tires. ``If a tire on a dual wheel blows, you still have one on that axle,'' Mr. Walenga said. ``If a wide-base tire blows, it's not a dangerous situation, but you can't limp into the next truck stop. They'll have to bring a tire out to you.''
Also, wide-base tires are heavy and difficult to handle manually. ``Do NOT use a steel wheel with a wide-base tire,'' Mr. Walenga advised. A wide-base tire's ride feels unstable to truckers used to dual wheels, but Mr. Walenga said that perception was erroneous, and that studies have shown wide-base tires to be very stable.
Meanwhile, the sport-utility vehicle boom has made truck drivers out of most American drivers, noted Guy Edington, managing director of the Kumho Technical Center in Akron.
Light truck sales-including SUVS, pickups, minivans, full-size vans and crossover vehicles-surpassed car sales in North America in the late 1990s, and by 2000 more than 7.5 million light trucks were sold there, as opposed to 6.8 million cars, Mr. Edington said. This compares with 1980, when cars outsold light trucks four to one.
Although light trucks are almost as old as the U.S. auto industry and have been around in some form since 1917, he noted, it wasn't till the 1980s that average car buyers were drawn to light trucks. ``In the '80s, a top-of-the-line pickup was priced thousands less than the coupes and sedans of that era,'' he said. ``Price, quality and a spacious cab attracted those tired of downsizing.''
The Chrysler minivan, introduced in 1984, ``showed us that cup holders were now more important than horsepower,'' Mr. Edington said. Minivans were more stylish than station wagons and appealed greatly to women, who-with greater responsibility for chauffeuring the family than before-played a greater role in the choice of vehicle.
He believes these events in turn paved the way for the SUV revolution of the '90s. ``We need four-wheel drive, safety and security, the ability to go off-road, and be surrounded by luxury while we're doing it,'' he said.
Even the threat of higher gas prices apparently hasn't stemmed the SUV tide. Mr. Edington quoted the research of AutoPacific, an auto industry marketing and product consulting firm, as showing that gas would have to top $2.58 a gallon before SUV drivers would consider changing their driving habits, and $2.85 a gallon before they would consider changing vehicles.
``One of the dirty little secrets about SUVs is that their gas mileage isn't good, but drivers don't care,'' he said. What this means for the tire market is probably not much, as long as LT tires offer a good ride, good mileage and respectable handling, he added. With the push for higher corporate average fuel economy, however, LT tires will have to improve their rolling resistance.
He noted that a Senate bill to increase CAFE 50 percent by 2014 failed to pass. ``But increased CAFE will happen, and soon,'' he said. ``Our country can't afford to keep going the way it's going.''
Rim diameters will continue to increase, Mr. Edington said, and run-flat tires probably will become original equipment on SUVs. ``Light trucks and SUVs need extended mobility,'' he added.