Heavy Duty Trucking

SEP 2014

The Fleet Business Authority

Issue link: https://heavydutytrucking.epubxp.com/i/382090

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58 HDT • SEPTEMBER 2014 www.truckinginfo.com back, the quietness is almost eerie. I couldn't hear it idle, and its working growl faded away as road speed increased. Cummins Westport G engines are spark-ignited; a diesel's compression ignition is more efficient, but produces that characteristic pounding sound. At highway speeds the chassis produced some muted mechanical whirring and tire whine, as well as the slight sound of air rushing past the mirrors and the cab's front corners. The ride was smooth, even with a stiff front suspension and the blocky 445-series tires. Acceleration was brisk as I departed and headed for nearby Wisconsin 26, a wide two-laner, and turned south, immediately encountering some memories. As a TV newsman many years before, I sometimes barreled north on this highway in a company car at up to 100 mph to get news film to the station in Green Bay in time for the 6 o'clock broadcast. This day I cruised at 55 to 65 mph, where the Cummins spun at 1,600 to 1,800 rpm — not wound out, but far faster than today's low-revving diesels in road tractors. This was the highest-rated ISX12 G, and with 400 horses, it had plenty of go-power. If it was consuming fuel at a fair rate, so what? Natural gas is much cheaper than diesel, so savings will help pay off the premium price for the natural gas fuel system. I turned right on a county road and followed it west and north a ways. I stopped and backed into a deserted intersection to reverse course and return the way I came. Maneuvering was easy and the view out the cab's windows and through its mirrors was fine, so I never used this test drive Truck: Oshkosh S-series front-discharge, rear-engine, center-cab mixer chassis, tare 33,950 lbs., GVW 80,000 lbs. Engine: Cummins Westport ISX12 G, 11.9 liters (726.2 cu. in.), 400 hp @ 1,800 rpm (2,100 governed), 1,450 lb-ft. @ 1,200 rpm Transmission: Allison 4500 RDS (Rugged Duty Series) full automatic, 6-speed double-overdrive Front axle: 23,000-lb. Oshkosh 23K w/ 5.63 final-drive ratio and Sheppard XD 120 integrated hydraulic power steering, on taperleafs Transfer case: Oshkosh 21000 2-speed Lift axle: 25,000-lb. Watson & Chalin AL-2200 non-steering Tandem axles: 46,000-lb. Meritor RT-46-160 on 46,000-lb. w/ 5.63 ratio, on Hendrickson Primaax air-ride Wheelbase: 196 inches Tires & wheels: 445/65R22.5 Michelin X2L, on 22.5x13-in. Alcoa aluminum discs Brakes: 16.5x7-in. S-cam at all wheels Fuel tanks: Two 37.5-diesel-gallon-equivalent (75-DGE total) Type 4 CNG (polymer core w/ carbon fiber wrap) Body: 11-yd. McNeilus forward-facing drum w/ ZF P7300 trans- mission and Eaton hydraulics SPECIFICATIONS The rear-mounted Cummins Westport ISX12 G can't be heard by the driver at highway speeds. Its gas is stored in twin vertical Type 4 CNG tanks just ahead. These replace four horizontal tanks previously used, saving about 500 pounds and allowing easier access to the engine. Filler's on the left side. truck's rear-view camera with its mini TV screen above the windshield. I meandered along other roads and onto city streets, and at one point did a couple of circles on a gravel parking lot. The wide tires limit wheel cut and make the turning circle a bit big, but it seemed to corner better than a conven- tional with a forward-set steer axle and wide tires. With Sheppard power steering, the truck didn't require much effort to turn, even while crawling. Upon my return, I parked it in front of the building. Recent rain had muddied a section of the back lot, where a line of new mixer and military trucks awaited transport to customers. I was tempted to jump back into the S and put its front-driving axle and lockable differentials on the rear tandem to a test, but didn't have the heart to get the shiny white rig dirty. Besides, I've seen them move through mud and know they're up to it. That's part of what makes this a seriously mobile and productive truck. n

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