APPEALING to fleets in weight-sensitive operations, Freightliner introduced its new lightweight version of the Century Class S/T tractor. Available in the same 112- and 120-inch lengths as standard Century Class tractors, the new version of the S/T pares off an estimated 1,200 pounds while maintaining all the technological features of previous Century S/T tractors.
The new tractor starts life with a core of lightweight components such as its aluminum cab that are already standard for the Century S/T series. The next step is to select lightweight options in place of standard equipment. These options may include the Mercedes-Benz MBE4000 engine, a 12.8-liter six-cylinder with horsepower ratings from 350 to 435. A 470-hp version will be available soon. More weight saving is available by specifying an aluminum frame crossmember under the engine instead of the standard steel crossmember. Equipping the engine with a horizontal exhaust system also cuts weight, because a horizontal mounting uses fewer brackets and less tubing than a vertical exhaust system.
A lighter drive train is available for fleets that select Eaton's new Lightning transmission. The Lightning uses a single aluminum case in place of the traditional main case and auxiliary housing found around transmissions with cast iron cases. In addition, the new transmission is shorter than traditional gearboxes.
In some applications, fleets can select a single drive axle in place of the more common tandem drive without losing any weight capacity. Freightliner recommends its AirLiner Plus suspension in combination with an ArvinMeritor RS-23-161 drive axle with an aluminum axle carrier. This 23,000-lb capacity drive axle in combination with an ArvinMeritor TR 8000 tag axle carries the same load as most tandem drives.
Additional weight reduction at the drive axles can be achieved by specifying Michelin's new X-One XDA 445/50R22.5 wide base tires, which reduce wheel and tire requirements by half. The new single tires save 115 lb per wheel end for a total of 460 lb per tandem compared to a tandem with eight conventional tires. To achieve this weight saving, the tires must be mounted on Accuride's new aluminum disc wheels for single tires. In addition to saving weight, the new single tire system provides a larger tire footprint than that available with conventional tires and can result in almost 5% fuel economy improvement. The X-One has the same radius as standard 22.5 low profile tubeless radial tires and can be used on trailers as well as tractors. The tires were tested for 60 million miles prior to introduction and will be an exclusive offering by Freightliner, Sterling, and Western Star for 30 months.
Front end weight can be reduced by using a composite spring front suspension in place of the standard steel spring leaf-and-a-half suspension used by Freightliner. Hendrickson's SteerTek fabricated front axle offers a significant weight saving in comparison to a standard forged I-beam front axle. The SteerTek has the same 12,000-lb capacity as standard front axles.
Cutting tractor weight is a matter of nibbling off small amounts in most cases. For instance, a few pounds can be saved by specifying Bendix DRM air dryers with integral aluminum reservoirs in place of systems with steel reservoirs. Lighter fifthwheels such as Jost's lightweight integral angle-mounted versions are available as well.
For more information, visit www.freight linertrucks.com.
