Class 8 Roundup

It's All About Fuel.

July 2008, - Test Drives

by Tom Berg, Senior Contributing Editor - Also by this author

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Aerodynamic design, long considered an important factor in achieving good fuel economy, is getting more attention from buyers, even if there'll always be a market for traditionally styled trucks, says Peterbilt. Meanwhile, Freightliner and International have been skirmishing with conflicting claims of aero superiority, the former using results from wind tunnel testing and the latter touting numbers gotten in track and on-road testing of competing models. Both suggest that possible fuel savings could go right to prospective customers' bottom lines, though previous industry studies and much fleet experience has shown that factors such as drivers' habits and traffic conditions have greater effects on fuel economy. 

Safety is getting more emphasis from some manufacturers, which are promoting various electronic safety devices while preparing to offer others. Volvo, for instance, has made electronic stability control standard on VHD mixer chassis, while sister company Mack has made the Bendix-produced products optional. Meritor Wabco electronic stability products are offered by tractor and trailer builders, while Eaton's Vorad collision-warning device has long been optional on many highway trucks. Lifeguard Technologies' RollTek, which combines side-curtain air bags with a seat-and-seat-belt restraining system, is a new crash-protection option on Freightliner's Cascadia. 

Adaptive cruise control, which alters a vehicle's speed as radar sensors react to traffic conditions, is available from some builders, and there's at least one aftermarket product. Even more advanced is a "predictive cruise control," which uses GPS and topographic mapping to establish a truck's location and modulate its throttle based on terrain. For instance, the system will know when the truck is approaching a downgrade and reduce power before it begins rolling downhill. Daimler Trucks North America (Freightliner, Sterling and Western Star), which will offer it starting early next year, says it can improve fuel economy by 2.5 percent. 

Comfort and convenience items continue to proliferate, partly for driver appeal but also with the idea that comfortable and well-rested people are safer and more productive. Lighter-weight but effective air-ride suspensions, including several new types for steer axles, are being introduced. Kenworth and Peterbilt now offer a front air suspension; Freightliner, which has offered a Hendrickson front air suspension, says it's coming out with a proprietary one early next year. 

A new, more economical engine, the turbo-compounded Detroit Diesel DD15, has joined Freightliner's lineup and is the preferred power for its long-nose Cascadia, which is getting three more sleeper options, along with a new medium-nose, 112-inch-BBC version. The shorter Cascadia will likely be powered by the MBE 4000 plus an anticipated DD13. Freightliner still produces Columbia and Century S/T aero highway tractors and traditionally styled Classic and Classic XL tractors, built on Century chassis, along with the premium Coronado. Early in '09, some of those models will be available with "predictive cruise control" that can save at least 2 percent in fuel (see main story). The FLD-SD (for severe-duty) continues as a truck and tractor, boosted by orders from the U.S. Army, but will drop out of the civilian market by the end of 2009 and be replaced by a new Class 8 vocational model. The upcoming work truck won't be based on the current Business Class M2 and M2V (for vocational) models which include Class 8 versions. Freightliner emphasizes its proprietary Mercedes-Benz and Detroit engines, including the Series 60, but offers Caterpillar's C13 and C15 in many of its Class 8 models. 

2009 will likely be the last model year for General Motors-built GMC TopKick and Chevrolet Kodiak midrange conventionals (shown) and T-series tiltcabs, as the deal to sell the line to Navistar International has proceeded quickly and was expected to close by the end of June. But the products will continue and GM commercial truck dealers will still sell them, though they'll come from a Navistar factory. Baby 8 versions use cabs and noses from medium-duty Cs with heavy duty frames, axles, suspensions, brakes and other appropriate chassis parts, combined with midrange powertrains, including the only gasoline engine, the Vortec 8100 V-8, still available in a Class 8 truck. Caterpillar's C7 diesel is optional, but increasing numbers of C-series trucks and tractors get the Isuzu-made 6H, which remains the only engine available in the heavy T tiltcabs. Whether Navistar will keep the GM-designed Baby 8s after the deal is a good question, but so is "why not"? 

The retro-styled LoneStar tractor (shown) goes into production later this year, and claims fuel-saving aerodynamics as well as chrome appeal. LoneStar will be International's highest-priced on-highway model, followed by the premium 9900i and 9900ix, and then by the ProStar. The ProStar began coming off the line at Chatham, Ont., early this year to replace the 9200 and 9400. The 8600 medium-nose regional tractor is being replaced by a TranStar, to be built at the Garland, Texas, plant. The 5000i premium vocational vehicles now carry the PayStar name, and Cat- and Cummins-powered versions of the 7000 series severe-service trucks have taller hoods to house bigger radiators for EPA-'07 diesels. A 7000 cab-chassis forms the basis for armored trucks that Navistar Defense builds for the U.S. military. Baby 8 versions of the DuraStar 4000 use International MaxxForce midrange diesels. Big-bore engines will be Cat's C13 and C15 and Cummins ISM and ISX; Cummins' ISL will be the lightweight engine in certain heavy applications, and International's own MaxxForce DT and HT 570 and DT 466 will go in others. Later this year, MaxxForce heavy duty diesels developed with MAN of Germany will debut. 

Kenworth's best-selling highway model is the T660 (shown), which is also KW's most aerodynamic, following an extensive redesign of the venerable T600 more than a year ago. The wide-cab aero T2000 continues into 2009 with updates it got for the last model year. The W900 and T800 soldier on in both highway and vocational duties, though there are rumors of a T8 restyling, perhaps by 2010 (or perhaps not). A T800 using a Cummins Westport natural gas engine is aimed for use in the Los Angeles Basin. The C500 remains the prime extra-heavy duty off-road truck, and some export versions are built with the flat-nose cab from the old K-series cab-over-engine models. KW's heavy diesel offerings include Cummins ISL, ISM and ISX, and Cat C9, C13 and C15. Paccar will begin building its European-designed 11- and 13-liter diesels in Columbus, Miss., by late next year, for use in Kenworth and Peterbilt heavies. 

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