Federal Researchers Confirm Claims Single Wide Tires Boost Fuel Economy
By Dan Leone, Staff Reporter
This story appears in the April 13 print edition of Transport Topics. Click here to subscribe today.
Federal researchers said they have confirmed manufacturers’ claims that single wide tires can boost a truck’s fuel economy, but one tire expert said they may not be suitable for every fleet.
The researchers’ findings, part of the Department of Energy’s Class 8 Heavy Truck Duty Cycle Project, found that using single wide tires on a truck’s drive and trailer axles can improve fuel efficiency 6% to 10%, compared with standard dual configurations.
For example, the heavier a truck’s payload, the greater the benefit from the switch to single wides, said Bill Knee, group leader for the transportation technology group at DOE’s Oak Ridge National Laboratory, Oak Ridge, Tenn.
“As we went from low to high weight, the marginal difference between the duals and the singles increased,” Knee said. “What that suggested to us was that you’ll get more of a marginal benefit the more weight you carry.”
While single wide tires offer better fuel economy at high payloads, compared with duals, Knee noted that increasing the weight of a load drives overall fuel efficiency down.
Oak Ridge published the report containing the data on single wide tires late last month. The 383-page document details research dating back to 2006.
Single wide tires were not originally slated to be part of DOE’s research, but Knee told Transport Topics, “When Michelin heard we were doing this . . . they said, ‘Can we piggyback on your test?’”
Oak Ridge testers agreed, and Michelin provided single wide tires to be fitted on six trucks and 10 trailers provided by Schrader Trucking Co., a regional truckload carrier in Jefferson City, Tenn.
Michelin, in a statement, said the agency’s report “confirms what our engineers and designers have said since we launched the Michelin X One nine years ago.”
Meanwhile, a representative of the Tire Industry Association, Bowie, Md., said the fleets that could benefit most from single wide configurations would see the biggest payback, not from better fuel economy but from a lighter truck.
“I don’t think that the fleets that are choosing those tires are doing it for the fuel,” Kevin Rohlwing, the tire group’s senior vice president of training, told TT in an April 3 interview. Single wide configurations “seem to be best suited for applications that are weight-conscious,” such as fuel or bulk hauling.
Replacing duals with single wide tires removes about 1,200 pounds from a truck-trailer combination’s total weight, Rohlwing said.
“The fleets looking at these super-wide tires are the ones that can see the gains from adding these extra 1,200 pounds of cargo,” Rohlwing said.
However, a fleet hauling consumer goods — which typically “cube out” before they “weigh out” — is less likely to benefit from single wide tires, better fuel economy notwithstanding, Rohl-wing told TT.
“Whatever fuel mileage gains are made by [single wides] are going to be offset by additional tire costs,” Rohlwing said.
Rohlwing also estimated that single wide tires cost “probably twice as much” as standard truck tires.
“The retreadability of [single wide] tires isn’t the same as the retreadability of standard tires,” Rohlwing said. Fleets “can get 500,000 miles out of a casing, and it has yet to be seen if those super wides can get that same type of mileage out of their casing.”
