Wide-Base Wheel Retrofits Can Save Money But Can Raise Maintenance Woes, Fleets Say

This story appears in the May 6 print edition of Transport Topics.

While wide-base wheels offer weight and fuel savings, especially when spec’d for a new truck, fleets need to be aware of the higher costs when retrofitting them and of the potential for maintenance problems if the job isn’t done right, suppliers and carrier executives warned.

Not only is converting existing equipment more expensive than buying new vehicles with wide-base wheels and tires, retrofitting them onto axles designed for dual wheels can lead to serious bearing and wheel problems, suppliers said.

Wheel manufacturers acknowledged the potential for problems and said carriers must be careful when retrofitting.

“Retrofitting works for some fleets but not all fleets,” said Brandon Uzarek, a field engineer for wheel manufacturer Accuride Corp.

Changing to a wide-base tire spec’d on a factory order “is almost cost neutral or [incurs] a very small upcharge,” said Jeff Robinson, senior vice president of maintenance for Tulsa, Okla.-based Melton Truck Lines. “Making changes and having them completed at the factory level is always the preferred way.”

Purchasing wide-base wheels and tires to replace duals on in-service trucks would have been “costly” for the fleet when it converted, compared to “just ordering [tractors] that way from the factory,” Robinson said.

Robinson cited a number of business and operational factors that he said argued against retrofitting. They include the cost of the original sets of duals and rims that already have been paid for; paying “a retail price” for four wide rims and four wide tires rather than getting them as original equipment; the truck’s downtime for retrofitting; and potential warranty implications.

“Today’s cost to buy a single aluminum wide-base wheel is approximately $900 per wheel; [that’s] $3,600 just for the wheels,” Robinson said. “Tires are anywhere from $950 to $1,200, depending on brand, so on the low side, $3,800, not including taxes and other charges. So to retrofit a current truck from dual to wide base would easily cost $7,500 or more.”

Then there is the risk of creating maintenance problems. Depending how it’s done, retrofitting a truck with wide-base wheels can change where and how loads fall on wheel ends, and that has implications for bearing wear and maintenance, some fleets and manufacturers said.

“I talked with people that have made the mistake of retrofitting because they see this [potential for] weight savings,” said Steve Dickson, vice president of maintenance for John Christner Trucking, headquartered in Sapulpa, Okla. “They think they can [put wide-base wheels on] a truck that’s got the standard bearing configuration for dual tires — and they come up having wheel-end failures,” such as bearing problems.

One key point, wheel and bearing manufacturers said, is using wheels with the correct offset, the distance from its hub mounting surface to the centerline of the wheel. Offsets can be zero, 1.13 inches or 2 inches, according to TireRack.com.

Wide-base single tires usually are mounted on a wheel with a 2-inch offset, which means the middle of the tread footprint on the wide single tire is approximately 2 inches farther outboard than the midpoint of a set of duals, said Mark Stangl, global product manager for automotive and heavy-duty aftermarket at bearing manufacturer The Timken Co., based in Canton, Ohio.

The 2-inch offset “affects the entire wheel-end system” on which the wide-base tires are mounted and “presents a series of challenges that make proper maintenance a priority,” Stangl said in an e-mail.

Dan Humphrey, manager of commercial vehicle aftermarket sales for Timken, added, “The load and the stress on the bearings are significantly [increased] by a 2-inch offset. That drives a reduction in bearing life.”

Other manufacturers had similar observations and recommendations, according to their products and field experiences.

Fleets “have got to be mindful of the different offsets for wide-base wheels,” said Dave Walters, manager of fleet service and warranty for Alcoa Wheel and Transportation Products. “With the bigger offsets [OEMs] are derating axles,” meaning the axles would be able to carry less weight.

“When retrofitting to wide-base wheels, one must first consult their axle manufacturer, [which] will be able to tell them if a 2-inch or ‘zero’ offset is needed for the axles application. A 0.5-inch offset is acceptable by all axle manufacturers in a ‘zero’ offset application. This will ensure that the loading point determined by the offset will not burn up the bearings in the wheel end, said Accuride’s Uzarek.

Meritor Heavy Vehicle Systems, based in Troy, Mich., advised in its technical literature that using wide-base single tires with offset wheels “may require more frequent inspections to detect any unforeseen axle or wheel-end conditions, depending on the severity of the vocation, as well as more frequent replacement of wheel-end components [bearings and seals], and axle and wheel-end lubrication.”

But that doesn’t mean existing equipment can’t be retrofitted, as long as it’s done properly. Spec’ing tractors with zero-offset wide-base wheels can help fleets reduce wheel-end issues and save money, wheel suppliers said.

Wheel manufacturers said that before replacing dual wheels with wide-base ones, longer wheel-mounting studs may be needed.

Uzarek said that when retrofitting from duals to an aluminum wide-base wheel, “you may have to increase the length of the studs because of the [greater] disk thickness” of the aluminum unit. He said aluminum “is a weaker material, therefore, in order to get the same strength as you would get in a steel [wheel, manufacturers] have to make that disk thicker.”

In addition to the weight and other savings of wide-base wheels, they can be beneficial to the brakes, suppliers said.

Alcoa’s Walters said that some models are designed with reduced wells to give more clearance over the brake drums, “one of the big benefits that’s overlooked with wide-base wheels.”

Because the brake drum is more exposed to air, it “definitely gets better cooling” compared to a set of duals,” Walters said.

Frank Bio, Volvo Trucks product manager, said the company follows “the rear-axle manufacturers’ requirements when it comes to the type of axle that accepts wide-base singles and the appropriate wheel offset.”

Jeff Cole, director of corporate communication for Dana Holding Corp., in Maumee, Ohio, said fleets need to take into account “their particular application, maintenance history, axle brand and wheel-end choices.”

Cole said carriers report “favorable” wheel-end performance and wheel-bearing life when operating Dana’s Spicer drive axles with wide-base tires in combination with Spicer LMS hub and nut systems spec’d on both original equipment and retrofits, where the fleet has followed the application guideline of both the OEM and Dana.

Erik Johnson, on-highway marketing manager for Kenworth Truck Co., said axle track, wheel offset and weight rating “all play into the wheel-end life.”

“For the most part, we will derate a rear tandem” from, for example, 40,000 pounds to 38,000 pounds, when it is spec’d on original equipment with wide-base singles, he said in an e-mail.

Johnson said there are dual-track axles that also work for wide-base singles, and Kenworth would recommend spec’ing such axles on a new truck “if a customer plans to retrofit from duals to [wide-base] singles and vice-versa.”

Melton Truck Lines phased wide-base wheels into its fleet by ordering them on new tractors over the past three to four years, said maintenance manager Robinson, adding that the carrier received about 400 tractors last year with the wide wheels and tires and has ordered about 250 more this year.

“Close to 100%” of the fleet’s 1,000 tractors now are equipped with wide wheels and tires, he said. “We’re having good luck with them.”

The single, wide-base wheels are made of aluminum, making them lighter than the steel rims commonly used in sets of duals.

“Being a flatbed fleet, we’re weight-sensitive,” Robinson said. “We save several hundred pounds going with the wide-base rather than the duals.”

Finding a tire tread that contributed the desired fuel savings and traction “took us a little while,” he added. “It’s working out well now.”

John Christner Trucking has 850 tractors and 1,100 temperature-controlled trailers. The carrier has spec’d wide-base wheels and tires on all new tractors since 2010, Dickson said.

“The wide base is a proven technology that improves mpg,” he said.

Single, wide-base tires on aluminum rims, mounted at the four drive positions on a Freightliner Cascadia’s tractor saves 400 pounds, Robinson said. “That’s a lot.”

While most fleets that use wide-base wheels are seeking weight savings and fuel economy, manufacturers said the fuel gains are more obtainable in certain vocations.

“That’s why you see it much more in linehaul operations rather than in city traffic,” with its stop-and-go driving and frequent turning, said Al Cohn, director of new market development and engineering support for San Antonio-based Pressure Systems International.

Trailers are less likely to be spec’d with wide-base wheels, manufacturers said, because payback comes slowly; tractors, usually in constant service, return the investment faster.

Craig Bennett, senior vice president, sales and marketing for Utility Trailer Manufacturing Co., based in City of Industry, Calif., said aluminum wide-base wheels amount to “10% to 11% of our build. So they’re not taking over the world, but with high fuel prices, they make a lot of sense.”

Many of the same potential concerns about wheel offsets and bearings apply in the case of trailers, Bennett said. The trailer maker recommends that a particular air-ride suspension be spec’d with single, wide-base wheels and tires because they allow a zero offset for the wheels, Bennett said.

“Having that wider axle track allows for the proper alignment of the wheel and wheel-end, to reduce bearing wear,” he said.

Wheel manufacturers said there definitely is a weight advantage of about 100 pounds per wheel-end to using wide-base wheels and tires.

Accuride, based in Evansville, Ind., makes a wide-base aluminum rim that weighs 59 pounds, Uzarek said. Alcoa Wheel makes a wide-base aluminum rim that weighs 58 pounds, said Walters, the fleet service manager.

Either rim, with a wide-base tire weighing about 220 pounds, adds up to a unit that weighs about 280 pounds, manufacturers said.

In contrast, one standard-size steel rim weighs close to 70 pounds, and its tire weighs about 110 to 120 pounds, the manufacturers said. That means one set of duals can tip the scales at about 380 pounds — or about 100 pounds more than one aluminum wide-base wheel with a tire.

But there is a significantly higher cost at the retail level than buying the units as original equipment.

Peggy Fisher, president of tire monitoring systems maker TireStamp Inc., based in Rochester Hills, Mich., said, “A wide-base tire runs around $1,150, and an aluminum wheel is around $400. These prices are retail and what a smaller fleet would pay. Large fleets get volume pricing, which would be discounted from these prices.”

Brian Thomas of Alcoa Wheel’s marketing communications office said, “While our retail distributors set final pricing, a typical Alcoa aluminum 14-inch wide-base wheel will retail for around $400 to $425 [per wheel] for a standard finish option. Same wheel with our proprietary Dura-Bright and/or Dura-Flange surface options will increase [the price] slightly. Distributors may extend some minimal volume discounts or even discounts with purchasing wheels and tires together, but that’s up to them.”