Will we ever see run-flat truck tires?: 'Outside-the-box technology' would be needed to overcome weight, heat and other issues
Several tire manufacturers are reporting that run-flat tires are gaining traction at the passenger tire level. But how would run-flat technology translate to medium truck tires? Can it be done? And would you -- or could you -- sell a run-flat truck tire?
"Of course we would," says Jim McCurdy, co-owner of Maine Commercial Tire Inc. in Bangor, Maine. "Unscheduled down time to repair or replace damaged tires is a tremendous expense."
"The quick answer is yes," says Jim Fenn, executive vice president of sales and marketing for Durand, Wis.-based Bauer Built Inc. "If it creates a value to the user, it would sell."
"If someone produced a technological breakthrough that works, there would be some validity to it," says Pat Duininck, president of Royal Tire Inc. in St. Cloud, Minn.
Are run-flat truck tires a potential reality or merely a pipe dream?
"If it wasn't going to be something that would seriously impact a fleet's cost-per-mile and it was a proven product that was going to allow them to still retread their tires, I think (fleets) would accept it," says Guy Walenga, engineering manager, commercial products, Bridgestone Firestone North American Tire LLC (BFNT).
However, producing a tire with those specifications is a tall order.
Hot and heavy
A number of factors would impede the development of run-flat truck tires, say tire manufacturers.
"You deal with so many issues in commercial products that you don't deal with in consumer products -- primarily weight," says John Cooney, director of commercial sales for Yokohama Tire Corp.
"It's a lot different to hold up a 10,000-pound wheel position (with one tire) than to hold up a 2,000-pound car with four tires. There's not a lot you can do to a sidewall to beef it up enough to hold 10,000 pounds."
"On a truck tire, the possibility for a 17.5- or 19.5-inch (run-flat) might exist," says Walenga. "But if we're talking 22.5-inch low profile, that's a lot of rubber to stick to a sidewall."
More rubber leads to more heat build-up, according to Al Cohn, manager of strategic initiatives for Goodyear Tire & Rubber Co.'s commercial tire systems. "Anything you do like that, you're increasing the heat. If you add stuff to a tire and it runs hot, it's not going to last very long, and you'll have retreadability issues."
Adding material to truck tires also increases manufacturing costs due to extra curing time, he says.
Other factors would make sidewall-reinforced run-flat truck tires a tough sell, according to BFNT's Walenga.
"I think ride would be dramatically compromised." Truck manufacturers might be able to offset that effect by using air spring suspensions and shock absorbers, but "ride is critical.
"I don't think a (reinforced sidewall) would be helpful in terms of overall rolling resistance. The rolling resistance of run-flats is not as good as more traditional tires.
"When you talk about fuel economy issues, fleets already have their backs against the wall. The last thing a fleet is going to look at is a tire that will further reduce what the fleet is already losing."
A run-flat alternative would be to build a center support ring into the tire that the tread would rest upon in the event of air loss, says Walenga.
"But I don't know if that's physically possible because of the size of (a truck) tire."
Mounting such a tire would require putting one bead on and then reaching in and inserting the support piece, he explains.
"Doing that with four tires on a car is one thing. But if you're doing it with 18 tires, there's a big labor quotient."
Going the distance
Let's say a run-flat truck tire could be made. How would it actually work?
"Could you run it for five miles, 50 miles, 500 miles?" asks Bauer Built's Fenn. "If it only gets you to a truck stop, it's not worth much; you get there already dragging a flat. "But if it gets you to the nearest maintenance terminal, then the value goes way up due to the implied road cost savings."
Goodyear's Cohn also has questions about how far run-flats could carry a rig.
"Most applications are dual tires," he says. "Since you already have limp-home capability, there's not a whole lot of interest (in run-flats). If one drive tire or one trailer tire goes down, you can slowly go to the next truck stop or service spot and make it in. We don't advocate that, but it's possible.
"In line-haul -- where you're primarily on the interstate system -- you're always close to a service spot."
"Everybody has seen a truck going down the highway with one flat tire just flapping away," says Yokohama's Cooney. "Unless you quickly remedy that situation, you'll lose the other tire" if you are using run-flats.
"Run-flat technology would have to be something that would continue to carry all the weight of the original tire in order to prevent the other tire in that dual assembly from failing."
Perhaps the biggest question is whether fleets would be willing to pay for run-flat truck tires.
"My feeling is that the manufacturers would only provide run-flat capability with some significant premium," says Maine Commercial Tire's McCurdy. "And that would doom the concept from the start."
Cooney agrees. "As we've found out with fuel efficient technologies and smart chip technologies, fleets don't want to pay (for premium technology). If it's free, they'll do it."
Short-haul fleets working in the waste and construction industries would most likely be more receptive to the run-flat concept than their line-haul counterparts because they experience more tire punctures, says Cooney. But even then, he adds, there would be a great deal of reluctance to pay extra for the benefits that a run-flat might provide.
"There's so much technology to be wrung out of tires as they are," says BFNT's Walenga. "What does a run-flat do? You're only talking about getting the vehicle to operate after you've incurred a blow-out.
"If your tire is flat because you have a slow leak, that's a failure of maintenance. Trucking companies hire tire professionals to do maintenance. This is a group that has maintenance procedures.
"There's always going to be a road hazard," he continues. "You're going to pick up a nail and not know it's there, and 10 or 15 miles later the tire goes down. But how often does that happen?
"I think we're pretty far away from run-flat truck tires. We're looking at things we can do to improve the products that are controlled by regular maintenance."