Ultra Low-Profile Single-Wide
Evan Lockridge
Contributing Editor
Single-wide truck tires seem to be doing something akin to the limbo dance - they keep getting lower and lower.
When low-profile single-wide tires were introduced about five years ago, they were touted as a new way to save on a truck's weight and, consequently, fuel consumption. Now there's a whole new generation of these tires that we'll call ultra low-profile single-wide tires.
There's not an official definition of an ultra low-profile single-wide, but in general, they are characterized by their aspect ratio. That is the ratio of the tire sidewall relative to the tread width, or the middle number you see in a tire size such as 425/65R22.5. In an ultra low-profile single-wide tire, that center number is smaller. In the North American market ultra low-profile single-wide tires essentially have a 50 or 55 aspect ratio.
The other thing that defines the new ultra low-profile single-wides has to do with the tire's architecture. In these tires you will find what's called a circumferential reinforcement ply in the crown, which is a casing ply that wraps around the tire perpendicular to the radial ply, stretching from the outside bead to the inside bead. This belt, along with the others in the tires, make these tires more stable on the road.
So what's the benefit of these ultra-lows over their slightly larger brothers?
"We are going to lower profile, because it tends, all things being equal, to be a more fuel-efficient product," says Guy Walenga, engineering manager with Bridgestone/Firestone. "It's simply an increase in benefits that you are already getting with a low-profile single-wide."
Because these ultra low-profile tires are smaller, that means less rolling resistance, which translates into better fuel economy.
"In our most conservative estimates, in converting the drive and trailer positions to wide-based tires, customers will experience a minimum of a 4% improvement in fuel economy," says Michael Burroughes, product manager for Michelin. "We have had customers report back as high as the 7% to 10% range."
The main reason for this savings is simple: weight - and less of it.
"One of these tires weighs about 70% of the weight of two duals," says Al Cohn, technical marketing manager for Goodyear. "Since the total weight of the tire and wheel is less, there is going to be less rolling resistance and the fuel economy is going to be better."
And there are other benefits.
"The tires are much more comfortable for the driver," said Burroughes. The features that offer more comfort also mean fewer flats. "It tends to be more absorbent over penetrating objects and they are less likely to penetrate the tread."
As with other single-wide tires, air pressure is easier to maintain and check, because you don't have to crawl under the truck or trailer to check the inside dual. Because the pressure is easier for drivers to check, tires are more likely to stay at the proper inflation.
The most likely candidates to benefit from ultra-low-profile tires are fleets that are grossing out before cubing out - hitting the truck's maximum payload capacity before you fill out the trailer. In this case, the weight savings of these new tires can translate to extra payload.
"This is the first tire technology that will increase revenue to the customer by allowing the customer to carry more payload," says Michelin's Burroughes. "The payback is phenomenally quick. Flying J and Pilot's payback on conversion was less than three months."
On a typical tractor-trailer, you could save 600 to 1,100 pounds, Walenga says. "It simply depends on what you are going from in terms of your tires and wheels and what you are going to."
For instance, if you are currently running dual steel wheels, your weight savings will be greater than if you are converting from dual aluminum wheels.
One factor slowing many fleets from converting to these tires is the investment in a new set of wheels for existing equipment, though a single-wide wheel costs less than two duals.
To help compensate, Michelin not only offers a satisfaction guarantee on these tires, including covering a portion of the cost of the wheel, but they also are offering financial incentives to get truck owners to convert.
Tire makers have also addressed concerns about their availability in the instance of roadside emergencies. All claim help is widely available through authorized dealers and at major truckstops, especially along the higher traffic corridors.
Another downside is mileage, although ultra low-profile tires are getting closer all the time to the traditional duals.
"On a drive axle you are generally not going to see the same removal miles you would on duals that you are replacing, but miles per 32nd rate of wear is pretty close," Walenga said, noting that the lower-profile tires have 4/32 to 6/32 less tread to begin with.
Tire makers are increasing their product offerings in the ultra low-profile single-wide tire lines to incorporate improvements in rubber compounds and tread design.
For instance, Goodyear is offering two entries into this field this year, one for trailers and one for the drive position. Michelin has introduced versions with different tread designs and different compounds for specific applications, such as regional highway applications.
