Driving Peterbilt's 357HH
Features include a big hood thathouses a big power Cat, and a setback steer axle designed for decent turning ability.
Tom Berg
Senior Equipment Editor
Think "heavy haul" and what comes to mind? How about a piece of earth-moving machinery on a long lowboy, pulled by a hefty road tractor? That's what we have here, and that tractor is one of two recently announced iterations of Peterbilt's popular 357.
Formerly offered only with a forward-set steer axle best used in bridge-formula states, the vocationally oriented 357 can now be purchased with a setback axle for those states that allow high-axle loads on relatively short wheelbases. One is Texas, where I drove this 357 Heavy Haul tractor.
Earlier this year Peterbilt announced the axle-back 357 in two bumper-to-back-of-cab measurements – 115 and 119 inches. The 357HH has the longer BBC, and it is set up to pull weighty loads at sometimes low speeds. Among other things, that requires both a powerful engine and a large radiator to shrug off high heat without help from the ram-air effect present during highway cruising.
This vehicle has a 625-horsepower Caterpillar C15 that's cooled by a radiator with a 1,440-square-inch core, which is about 20 percent larger than radiators on other 357s. Its hood and nose are likewise wider, and seem to thrust ahead of the rear-set axle, making for a brutish look that tells everyone that this truck means business.
This was the first 357HH built and was at Rush Peterbilt on Houston's east side. So that's where I headed. Peterbilt spokesman Derek Smith had made the arrangements with the dealership and its next-door sister store, Rush Equipment, which sells John Deere construction products.
Our load was a Deere front loader/backhoe aboard a 53-foot-long by 102-inch-wide Fontaine tri-axle lowboy. The Deere weighed only about 14,000 pounds, so a short equipment trailer would have sufficed. But I had asked for a lowboy and that's what the crew provided. The trailer had a manual gooseneck, which locals call a "dropdeck" to distinguish it from one with a hydraulic gooseneck.
The tractor's setback steer axle provides more room for the front wheels to cut, so the turning circle is about 13 percent smaller than a regular 357, according to factory-provided numbers. But the trailer was still a chore to pull because of its sheer length and the absolute rear setting of its axles. Any sharp turn had to be taken wide to give the trailer room to follow.
Coming out of the dealership's driveway onto a freeway frontage road, I had to climb the opposite curb and move the tractor along the dirt and grass until the trailer's tridem cleared the fence, then swing the tractor back onto the pavement. For the rest of the trip I was careful where I went with this rig because I didn't want to find myself boxed in.
For the most part I stayed on freeways, driving a roundabout route west on Interstate 10 and north on State Route 45. Then I backtracked to I-610, which took us east and south to the dealership back near I-10. Lanes were narrow on older stretches of the freeways, providing maybe a foot on either side of the wide trailer. Traveling on these was a trifle tedious, because I had to constantly watch the trailer's position through the mirrors. Using the Peterbilt's winged nose ornament to sight along our lane's right edge helped here. Newer segments had wider lanes where I could relax.
With 625 horsepower and a light load, acceleration and cruising were both effortless. I never needed the transmission's Low gear and instead started out in first or second. I split the 18-speed's main gears mostly for fun and otherwise drove it like a nine-speed. The engine spun a bit over 1,600 rpm at 65 mph in top gear, so the tractor was as sufficiently long-legged as it was low-geared for starting out with heavy loads. The tranny was new-truck stiff but nonetheless shifted smoothly and with a nice, tight feel to the lever.
As we turned around at a road junction north of the city, I was reminded that while outboard-mounted exhaust stacks look neat and keep the rear deck clear for extra long loads, the one behind the driver's window blocks his view of what's happening with the trailer's left-rear corner during tight turns. But the big convex spot mirror was enough to watch the tridem's wheels to be sure they weren't running over something or somebody.
In right turns I could look over my shoulder and out the cab's big rear window, which gave me a clear view of the entire trailer. In sharp turns it was nice to know that I could aim the nimble Pete's nose far outside the circle needed by the trailer, then easily cut back in.
The 357HH will come standard with a tilting steering wheel, but this pre-production tractor didn't have it. The wheel was higher than I'd have set it but low enough to be comfortable. However, its thick rim and wide spokes blocked my view of several gauges and the warning light display. As I leaned forward I saw a steady red light labeled "Trailer ABS." The tractor's electronics had sensed that the 10-year-old trailer had no anti-lock braking system. That's nice to know because in a panic stop, especially on slippery pavement, the ABS-equipped tractor will stay in line but the trailer's tail may swing out as you jam on the binders.
That was not a problem on this day, unless high humidity makes pavement slick. Humidity and temperature were both in the 90s, giving the 357HH's air conditioner a good workout. It was up to the job, as was Smith, who occupied the solid-mount passenger seat and uttered no complaints about the ride. The tractor rode on two sets of air bags, one over the tandem and another at the cab's rear mounts, and my air-ride seat constituted a third level of cushioning as the tractor's front end hopped slightly over bowed concrete.
In summing up, Peterbilt's 357HH is a special tractor for specialized hauling that looks like a brute but behaves like a gentleman. It's one of the better ways to handle big and heavy loads.
