In the U.S. Environmental Protection Agency’s SmartWayTransport Partnership’s specifications for Class 8 combination vehicles,lighter-weight tractor and trailer components are recommended as potential fuelsaving options. Reducing 3,000 lbs. from a heavy-duty vehicle, EPA notes, couldsave between 200 and 500 gallons of fuel each year.
“Truck fuel consumption increases with the weight of thevehicle,” EPA SmartWay programliterature states. “Heavier trucks require more fuel to accelerate and to climbhills and every ten percent drop in truck weight reduces fuel use between fiveand ten percent. Using aluminum and other lightweight components whereappropriate can reduce empty weight, improve fuel efficiency, and reducegreenhouse gas emissions.”
Most truck manufacturers, EPA goes on to note, offerlightweight models that are 1,000 or more lbs. lighter than comparableversions. Lighter-weight models combine different weight-saving wheel-endoptions that may include aluminum wheels. SmartWay specs also include arecommendation for using optional low rolling resistance wide base single tiresmounted on aluminum wheels.
Wide base wheels
In turn, wheel manufacturers are offering aluminum wheels in22.5×14-in. sizes to help bring additional weight and fuel savings to fleets.Alcoa notes that some fleets have experienced savings of 3% to 7% with widebase wheel and tire combinations. Estimates from Accuride include 2.5 % fuelsavings per tractor and 5% per combination vehicle.
Wide base wheel and tire 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 theamount of drag created by tires as the vehicle runs down the highway. Part ofrolling resistance comes from the flexing and un-flexing of the tire as itrolls into and out of contact with the pavement.
Actual weight savings with wide base aluminum wheels vary bymanufacturer. Alcoa’s 14-in. wide base aluminum wheels, according to thecompany, can save 318 lbs. per axle or 1,272 lbs. per combination when used inplace of dual wheels on drive and trailer positions. The wheels, which weighonly 68 lbs. each, are load rated up to 12,800 lbs.
Accuride DupleX-One wide-base 22.5×14-in. aluminum wheels,the company notes, reduce fuel expense or increase payload capacity when usedin place of traditional dual wheel sets on tandem-axle tractors and trailers.Developed in conjunction with Michelin, the forged aluminum wheels can save 120lbs. per axle.
Lower costs
Additional benefits of wide base single tires and wheels,the manufacturers also point out, include reduced maintenance costs. Thoseexpenses are lower, they say, because there are only four wheels per tandemcompared to eight. In addition, without an inner wheel, inflation and visualinspection becomes much easier and more effective. Wide base aluminum wheelsalso tend to help keep brake packages running cooler and therefore lastinglonger.
Adding it all up, when it comes to using larger wide basesingle wheels in place of traditional dual tire assemblies, bigger may bebetter in terms of spec’ing for improved fuel efficiency.
For information about wide base aluminum wheels:
Accuride:www.accuridewheels.com
Alcoa:www.alcoawheels.com
Webb Wheel Products said it has designed Vortex drums tomeet the demand for a lighter weight grey iron drum with better performancefeatures and a lower cost than current lightweight drums available for heavytrucks and trailers. Benefits are:
• Thermal advantage: The Webb Vortex drum runs cooler anddissipates heat faster than steel-shelled light weight brake drums.
• Weight advantage: 12 lbs. per wheel end advantage overstandard grey iron drums
• Performance advantage: Vortex drums run cooler than thecompetition and exceed all FMVSS121 requirements for brake torque, brake powerand brake recovery. Every drum isprecision balanced and rated at 23,000 lbs. GVW.
• Maintenance advantage: Because Vortex runs cooler, brakesare more effective and last longer resulting in more uptime and lessmaintenance costs, the company says.
• Cost advantage: $200.00 savings per tandem axle vs. steelshelled drums.
For more information:www.webbwheel.com/vortex
The use of wide base single tires on drive and trailer axlesby fleets is growing. Among the products available for on-highway Class 8vehicles include the following offerings:
Bridgestone Greatec wide base radials are available in driveand trailer tread designs in a 445/50R22.5 size, equivalent in overall diameterto regular low-profile radials for 22.5-in. wheels. Maximum load capacity ofeach Greatec radial is 10,200 lbs. at 120 PSI, and the tires may be used at amaximum sustained speed of 75 MPH.
Depending on the types of tires and wheels converted,according to Bridgestone, Greatec radials could reduce overall vehicle weightby 600 to 1,200 or more lbs. In addition to directly converting lower vehicleweight into payload, Bridgestone says that Greatec radials could also providefuel economy advantages, saving approximately two to five percent on vehiclefuel consumption by comparison to conventional, non-fuel-efficient dual tireassemblies. Actual fuel savings will vary, depending on vehicle configuration,how many axles are converted, what tires were used previously and otherfactors.
For information, visit www.trucktires.com
