Study says 6×2 axles average 2.5 percent better fuel mileage
In collaboration with the Carbon War Room initiative, the North American Council for Freight Efficiency announced results of a study of existing literature on, as well as new track tests of, 6×2 tractor axle configurations and fuel efficiency versus that achieved with more common 6×4 set-ups. Tests examined and performed showed a range of increased efficiency, from as little as 1.6 percent to as much as 4.6 percent — NACFE concluded an average 2.5 percent could be expected for many fleets with a conversion to a 6×2 configuration.
Kevin Rutherford, writing as part of the Dollars and Sense column in Overdrive in April last year, noted he rarely recommended conversion to 6x2s to owner-operators given the long payback time with a cited 5 percent boost in fuel mileage. The NACFE report, however, notes that owners “can be confident that they will enjoy about a 2.5% reduction in fuel use, and payback on investment in about 20 months, by adopting currently available 6×2 axle technologies.”
The 6×2 “confidence report” in NACFE’s Trucking Efficiency series follows reports on speed limiting technologies for fleets and wide-single tires — in the latter case, 3 to 6 percent greater fuel efficiency was cited as a reliable estimate for operations where singles were a possibility.
Report authors hoped results would “catalyze significant new interest in the 6×2 axle technology as a way to increase fuel efficiency and obtain other benefits.”
Some particulars of the analysis and tests in the 6×2 report can be found in the chart below. Download the summary report via this link.