In the U.S. Environmental Protection Agency’s SmartWay Transport Partnership’s specifications for Class 8 vehicles, lighter-weight tractor and trailer components are recommended as potential fuel saving options.
Reducing 3,000 lbs. from a heavy-duty vehicle, EPA notes, could save between 200 and 500 gallons of fuel each year.
“Truck fuel consumption increases with the weight of the vehicle,” EPA SmartWay program literature states. “Heavier trucks require more fuel to accelerate and to climb hills and every ten percent drop in truck weight reduces fuel use between five and ten percent. Using aluminum and other lightweight components where appropriate can reduce empty weight, improve fuel efficiency, and reduce greenhouse gas emissions.”
Most truck manufacturers, EPA goes on to note, offer lightweight models that are 1,000 lbs. or more lighter than comparable versions. Lighter-weight models combine different weight-saving wheel-end options that may include aluminum wheels. SmartWay specs also include a recommendation for using optional low rolling resistance wide base single tires mounted on aluminum wheels.
In turn, wheel manufacturers are offering aluminum wheels in 22.5x14-inch sizes to help bring additional weight and fuel savings to fleets. Alcoa notes that some fleets have experienced savings of 3% to 7% with super wide tire and wheel combinations. Estimates from Accuride include 2.5 % fuel savings per tractor and 5% per combination vehicle.
Super wide tire and wheel assemblies save fuel, in part, because they include only half as many flexing sidewalls as a set of duals. Tire rolling resistance, a major factor in a tire’s fuel efficiency, is the amount of drag created by tires as the vehicle runs down the highway. Part of rolling resistance comes from sidewall flexing as the tire rolls into and out of contact with the pavement.
Actual weight savings with super wide aluminum wheels vary by manufacturer. Alcoa’s 14-inch aluminum wheels, according to the company, can save 318 lbs. per axle or 1,272 lbs. per combination when used in place of dual wheels on drive and trailer positions. The wheels, which weigh only 68 lbs. each, are load rated up to 12,800 lbs.
Accuride DupleX-One 22.5x14-inch aluminum wheels, the company notes, reduce fuel expense or increase payload capacity when used in place of traditional dual wheel sets on tandem-axle tractors and trailers. Developed in conjunction with Michelin, the forged aluminum wheels can save 120 lbs. per axle.
Additional benefits of super wide tires and wheels, the manufacturers also point out, include reduced maintenance costs. Those expenses are lower, they say, because there are only four wheel positions per tandem compared to eight. In addition, without an inner tire/wheel, inflation and visual inspection becomes much easier and more effective. Super wide aluminum wheels also tend to help keep brake packages running cooler and, therefore, lasting longer.
Adding it all up, when it comes to using larger single tires and wheels in place of traditional dual tire assemblies, bigger may be better in terms of spec’ing for improved fuel efficiency.
The use of super wide single tires on drive and trailer axles by fleets is growing. As more and more of these tire/wheel products come on the market, there will be many claims of fuel efficiency, weight and cost gains for fleets. As the dealer, it will be up to you to help your fleet customer navigate these claims and products and choose the most effective for their unique needs.