Peterbilt 567SFFA For ‘Formula’ States

May 26, 2015

Weight laws in some “bridge-formula” states favor trucks with set-forward front axles, which is why Peterbilt Motors added the SFFA configuration to its Model 567. The vocational vehicle came out two years ago with a set-back front axle that’s generally more usable in “axle-weight” states. The 567, which features a wider, roomier aluminum cab and chassis improvements, is becoming popular with customers, so the narrow-cab 365 and 367 will eventually be withdrawn as their sales wither.

If frame length and placement of rear axles remain the same, a forward-set steer axle on the 567 lengthens a wheelbase by 17.9 inches, adding legal payload. How much varies with the states, but it’s enough to make up for a sacrifice in turning ability and a harsher ride in most trucks. But Peterbilt engineers have minimized the usual maneuverability limits and all but eliminated a ride penalty. With a wheel cut of 43 to 45 degrees, this truck turned fairly well and rode very well. 

Test Set

  • Truck: 2015 Peterbilt 567SFFA (set-forward front axle),conventional-cab vocational chassis, 5/8x11-5/8-in. frame rails w/ aluminum crossmembers, BBC 115 inches, GVWrating 80,000 lb.
  • Engine: 12.9-liter (788-cu-in.) Paccar MX-13; 500 hp @ 1,700 rpm; 1,850 lb-ft. @ 1,100 rpm, w/ engine brake
  • Transmission: Allison 4700 RDS-P 7-speed automatic w/ 2nd Reverse
  • Steer axle: 20,000-lb. Dana Spicer D-2000F w/ Sheppard HD94 dual hydraulic power, on taperleafs, w/ Bendix air disc brakes
  • Lift axle: 13,500-lb. Watson & Chalin SL1190SSR self-steering, w/ Bendix 16.5 x 7-in. S-cam drum brakes
  • Rear tandem: 46,000-lb. Dana Spicer D46-170 w/ 4.10 gearing, on Peterbilt Air Trac air suspension, w/ Bendix air disc brakes
  • Wheelbase: 243 inches
  • Tires & wheels: Bridgestone 425/65R22.5 M860 front, 11R22.5 M799 rear, on Alcoa Dura-Bright polished aluminum discs
  • ABS: Bendix 6-channel w/ Electronic Stability Program
  • Fuel capacity: 100 gallons
  • Body: East Genesis 17.5-ft., 22-yd. polished aluminum dump

Peterbilt’s marketing department is sending this sharp metallic red truck with its East polished-aluminum dump body on demonstration visits to dealers around the country. With help from company spokesman Derek Smith, I caught up with it at Peterbilt of Cincinnati in Sharonville, Ohio, a northern suburb along the I-275 beltline. Smith was flying up from headquarters in Denton, Texas, and until he arrived I chatted with salesman Lyle Monroe about the axle layout.

Rears included tandem drivers and one liftable, steerable “pusher” axle ahead of the tandem. This is called a “tri-axe” in neighboring Indiana, and it was the usual type used there until higher-capacity “quads”—tandems with two pushers—were authorized, Monroe said. The tri-axe is also allowed in Kentucky, just across the Ohio River; in Pennsylvania, to the east; and elsewhere, though they usually have beefier wheels and tires to gain maximum weight-carrying ability. Ohio is a bridge-formula state where multi-axle dumps with two, three and even four pushers are the rule. A tri-axe is not usually seen here.

“So I was kinda conservative with the load I put in there,” Monroe said. “You’ve got 12 tons of sand. That should give you a good feel for how it handles.” He was right, as 24,000 pounds in the box settled down the suspensions and yielded a realistic riding experience. It also taxed the powertrain enough for me to appreciate its strength and smoothness. We posed this truck next to a current 567 to shoot a few photos that show the difference in steer-axle positions, then Smith and I climbed in the new one and we prepared to trundle off.

But first I remarked that the steps outside the cab were set up just right: an even one-two-three climb up and into the cab. Earlier, when moving the vehicle for the picture-taking, I barely had a chance to look around inside before I got a whiff of the pleasant aroma given off by the soft leather coverings on the seats, which can be heated in cold temps or to soothe backaches—not your usual fare in a work truck. But this was built for show as well as work, and its appearances had included the Mid-America show in Louisville in March.

Other interior appointments were likewise deluxe, with bright-metal trim around gauges and a nice grade of plastic in two-tone gray forming the various panels. I’ve got an older Lexus RX that looks like this inside. Usually I’d object to a light color adjacent to the windshield because it usually glares into the glass, but not on this truck, and after some initial clouds the day was sunny and bright.

Outward visibility was superb through the large side windows and windshield, and over the sloped hood, which bends downward toward its nose and gives a better “strike” view of the ground ahead, Peterbilt’s vocational segment manager, Charlie Cook, had said when the original 567 came out two years ago. The cab’s width is 82.7 inches, which I think is just about right for this kind of truck. The cab is about 8 inches more than the old but famously stout cab on the 367 and other earlier Petes, but this new one is also tight and quiet. There’s plenty of legroom, and the tilting-and-telescoping steering column combined with the highly adjustable Peterbilt-brand driver’s seat let me position myself for viewing, pedal pushing, and perching.

Monroe put an Ohio commercial license plate inside the winshield so we should have been legal in both of the surrounding states, but I decided to preclude any complications by staying within Ohio. He lent us a Rand McNally atlas, but I decided instead to be a smarty pants and use the map app on my smart phone; I picked a route that combined some freeway travel with state highways that took us on a moderately lengthy loop north and east of Cincy’s metro area. We did some urban and country running on flat and roller-coaster terrain, more than enough for me to appreciate the Paccar MX-13 diesel’s 500  horses and freedom from shifting presented by an Allison 4700 automatic transmission.

Right away I noticed that the truck turned in a respectable circle, not near as sharply as some highway tractors with setback front axles, but sharper than I’ve come to expect from a forward-set axle with four-and-a-quarter-size tires and wheels. Mounted forward, they’re part of a less maneuverable longer wheelbase; and being wide, they seldom have enough room to cut toward the frame rails, which they do no matter which way they’re swung. But on this truck they somehow did. I didn’t have to spin the steering wheel immediately upon starting into a 90-degree turn, as I have previously found necessary with such a setup, and only once had to use an opposing lane to complete a right-hand swing, and this was in an acute angle turn, maybe 80 or so degrees, at a rural intersection. 

The ride was smooth: smoother than a stiffly sprung dump truck with a 20,000-pound steer axle should be, especially given the relatively short leaf springs on which the axle is suspended. The tandem rears rode on a Peterbilt Air Leaf suspension. Overall ride was pretty good on the sometimes mildly bowed concrete of I-75 and 275, and really good on the uniformly smooth asphalt of the state routes that I happened to choose.

Handling through curves was almost crisp, thanks again to the suspensions, plus the Bridgestone tires and the stable Sheppard power steering. There was no leaning but no rough coaster-wagon sensation, either. Braking was strong and stable, thanks to disc brakes all around. At one point, while drifting down a short hill and braking for a 45-mph left-hand curve, I told Smith, “This is probably the nicest dump truck I’ve ever driven.”

But since saying that I went back and looked at the article I did almost two years ago, on the original 567 dumper with a set-forward front axle. I thought that one was swell, as well. In January, Peterbilt entered one of those in the American Truck Dealers’ annual Commercial Truck of the Year competition and…it got beat by a Kenworth T880 dumper (which uses the same basic cab, by the way). Why? Because that Pete had a more plain-Jane interior and a Cummins natural gas engine with 100 fewer horsepower, and therefore the truck wasn’t as pleasant to drive. For straight go-ability and strong feel, a good diesel like the MX-13 is hard to beat, which is why diesels are in a huge majority of Class 8 trucks.

Now with the forward-set front axle, the Pete 567 can serve more markets and more applications. How well drivers will like them depends on how they’re set up, for sure. But not everyone wants fanciness, and a more basic Peterbilt will please such folks with its comfort, reliability, durability and yes, the mystique that comes with that red oval badge.