Lightweight Peterbilts Boost Bulk-Hauler Payloads

Sept. 28, 2010
Peterbilt truck Cummins ISM Engine


Cummins ISM, which scales about 800 pounds less than an ISX, is the single biggest weight saver. It's gutsy enough for running in mostly flat terrain.


Peterbilt-Heil combination takes on 54,600 pounds of cement at a plant near Coover Trucking's office at Humboldt, Kan. Model 365's traditional styling appeal to owner Dave Coover and his drivers. Tractor's lightweight specifications help a rig carry profitable payloads.

Specifications

Tractor: 2008 Peterbilt 365, conventional-cab w/36-inch sleeper, BBC 115 inches, w/many aluminum components, Holland fixed fifth wheel

Engine: 2007-spec Cummins ISM, 10.8 liters (660 cubic inches), 410-hp @ 2,100 rpm, 1,550 lbs.-ft. @ 1,200 rpm

Transmission: Eaton Fuller FRO15210C 10-speed

Front axle: 12,000-lb. Dana Spicer E1220I on 14,600-lb. Parabolic leafs

Rear axles: 40,000-lb. Dana Spicer DSP40 w/3.55 ratio, on Peterbilt Air-Leaf

Wheelbase: 216 inches

Brakes: Spicer S-cam w/Bendix ABS

Tires & wheels: Bridgestone R280 (front), M720FE (rear); 295/75R22.5 on Alcoa aluminum discs

Fuel tank: Single 120-gallon aluminum

Trailer: 1,040 cu-ft. Heil 1040 Cementer aluminum, pneumatic off-loading

Payload and reliability are everything for Dave Coover, owner of Coover Trucking, whose fleet of 14 tractors and pneumatic-tank trailers are kept busy hauling bulk cement for construction projects in Kansas and surrounding states. That's why he runs eight efficient, lightweight, late-model Peterbilt 365 tractors like the one shown here.

Looks are also important, partly for "driver acceptance," he said, and that's why he was attracted to the Model 365, a vocational type usually used as a dump and mixer chassis. It has a more boxy nose than aerodynamic models, and is arguably more practical because of its hood-mounted halogen headlights and detachable fenders that are easily repaired or replaced.

Coover and his drivers prefer the traditional look, and they've accepted the 365s after driving trucks like Kenworth's W900.

Driver David Huff is assigned to our subject tractor, an '08, which I took on a short test run for this article. He's 62 and has 20 years driving experience, the last four with Coover. He said he preferred a W9 he previously drove, but the 365 was OK, too. Coover said Huff is among his most conscientious drivers and washes the tractor and Heil pneumatic trailer several times a week.

This was a rainy day and most trucks were idle. Coover had Huff pick up a load that could go out later. He loaded up at a Monarch Cement plant across the road from Coover's office at Humboldt. The powdery product that poured into the 41.5-foot Heil tanker weighed 54,600 pounds, according to the plant's scale; with the rig's tare of 25,460, that put us at 80,060 pounds — slightly overweight because of me.

The tare included 14,500 pounds for the sleeper-cab tractor — probably closer to 15,000 with both of us aboard — which is about 3,000 pounds less than a typical over-the-road tractor. All of the savings go to payload, which adds about a nickel-a-mile in revenue. Coover collaborated on spec'ing with Ryan Saner, branch manager at Peterbilt PacLease of Springfield, Mo., who set up a lease of the eight Petes. Coover said he insisted on low weight and Saner looked over everything.

A 365 is basically light in weight, though by only a few pounds compared to a highway-type 386, Saner said. A "small-block" diesel — Cummins' 11-liter ISM — is the single greatest weight saver. It scales about 800 pounds less than a 15-liter ISX, a more common highway engine.

The "little" 410-horsepower Cummins pulled well on a run in the area. And the Fuller 10-speed Roadranger had just enough ratios for any situation, especially considering the flat highways of southeastern Kansas. I wasn't at my shifty best on this day, as I missed a few gear changes, mostly because I wasn't familiar with the tractor, and 60 or so miles wasn't enough to become so. The clutch pedal needed a strong leg to operate, which is typical of Peterbilts.

The Pete rode firmly, which is partly a function of the 14,600-pound springs over the 12,000-pound steer axle. Saner said Peterbilt insists on using the heavier springs with a forward-set steer axle for durability. Visibility over the sloped hood to the front and sides was very good; an extra convex mirror above the right fender was useful in checking traffic alongside.

The cab sits moderately high off the ground and it's a healthy climb up. The cab's interior features a rather complete set of gauges set off by woodgrain dashboard trim. Seats are cloth-covered and cool. The floor mat is no-nonsense rubber, and the overall impression says "work truck." That's echoed by beige exterior paint, which Coover chose because it doesn't show the cement that inevitably dusts the rig during loading and unloading.

Aside from the engine, the Pete's lightweight parts include aluminum cross members, hubs, wheels, tanks and boxes. A single exhaust stack weighs less than dual stacks, but it's smartly trimmed with chrome. A Holland fixed fifth wheel is lighter than a slider. Coover knows he could save about 800 pounds by going to wide-base single tires on the rig's two tandems, but "when one of those tires goes down, the truck goes down." So he stays with low-profile duals to ensure reliability.

A tractor carries a single aluminum fuel tank which holds up to 120 gallons — enough in this out-and-back operation. Diesel fuel weighs about 7.5 pounds per gallon, so carrying more would only reduce payload. Fleet fuel economy averages 5.8 to 5.9 miles per gallon in the cool spring months and in the low 6-mpg range in summer, Coover said. This is about the same as the Caterpillar C-12s and C13s in his older tractors.

To meet 2007 federal emissions regulations, the ISMs have variable-geometry turbochargers, exhaust-gas recirculation, and diesel particulate filters. These make the engines burn so cleanly that there's no exhaust odor and no visible smoke at all. The electronic controls and circuits that operate them and the components themselves are complex and not without problems, which has been the case with all modern diesels, Coover noted.

However, the full-service lease agreement means Coover doesn't have to worry about trying to maintain them. Some of his rigs make deliveries near Springfield and Joplin, where the Peterbilt-PacLease dealer has shops, and work can be done there. Saner said he checked out and authorized an independent shop close to Coover's operating base to do routine servicing and repairs.

So, here are some specs and a business arrangement that work here. How good are yours?

 

Specifications

Tractor: 2008 Peterbilt 365, conventional-cab w/36-inch sleeper, BBC 115 inches, w/many aluminum components, Holland fixed fifth wheel

Engine: 2007-spec Cummins ISM, 10.8 liters (660 cubic inches), 410-hp @ 2,100 rpm, 1,550 lbs.-ft. @ 1,200 rpm

Transmission: Eaton Fuller FRO15210C 10-speed

Front axle: 12,000-lb. Dana Spicer E1220I on 14,600-lb. Parabolic leafs

Rear axles: 40,000-lb. Dana Spicer DSP40 w/3.55 ratio, on Peterbilt Air-Leaf

Wheelbase: 216 inches

Brakes: Spicer S-cam w/Bendix ABS

Tires & wheels: Bridgestone R280 (front), M720FE (rear); 295/75R22.5 on Alcoa aluminum discs

Fuel tank: Single 120-gallon aluminum

Trailer: 1,040 cu-ft. Heil 1040 Cementer aluminum, pneumatic off-loading