Equipment Type

T880 Mixer Focuses on Engine, Axles

A new spec for Stoneway Concrete cuts weight, adds payload and revenue

June 22, 2016

The silver-gray T880 mixer chassis sure looked familiar as it sat near the entrance to Kenworth’s plant in Chillicothe, Ohio, on a cloudy May day. That was because “it’s a carbon copy of a Stoneway truck,” said Kurt Swihart, KW’s marketing director, one of the people on hand to greet me. He referenced a similar vehicle I had seen and ridden in out in Seattle last fall, during a sneak peek at the new Paccar MX-11 diesel. Sure enough, I said, although I’ve since looked at photos I had shot back then, and see that the medium-blue trim on the truck here doesn’t match the bright-red accents that Stoneway Concrete uses on its new fleet of T880s.

Still, the mechanical components are the same, including the McNeilus 11.5-yard barrel, the chassis’ 256-inch wheelbase, three steerable and liftable “pusher” axles, and the swing-down “booster” axle bringing up the rear. They work well with the T880’s set-back steer axle, which can shoulder up to 20,000 pounds. The booster tends to push weight forward, onto the steer and pusher axles, but also carries up to 13,000 pounds of its own and lengthens the truck’s legal “bridge” by about 15 feet. Thus, in Federal Bridge states like Washington it can legally gross up to 80,000 pounds and carry up to 12 cubic yards, a yard more than older trucks that can gross 76,000. That means one of the new trucks can earn an average of $315 more revenue per day, and fewer short loads need to go out to finish a pouring job, according to Ralph Lo Priore, director of fleet assets and processes.

Test Set

Truck: 2016 Kenworth T880 “Bridge Mixer,” conventional daycab, BBC 116.5 inches, GVW 80,000 lb.

Engine: Paccar MX-11, 10.8 liters (660 cu. in.); 430 hp @ 1,700 rpm; 1,550 lb.-ft. @ 1,000 rpm; w/ engine brake

Transmission: Allison 4700RDS, 7-speed, w/ 7.63 1st gear and double overdrive

Front axle: 20,000-lb. Meritor MFS20, on 20,000-lb. taperleafs

Drive axles: 46,000-lb. Meritor 46-164EH w/ 4.56 ratio, on 46,000-lb. Hendrickson HMX460

Brakes: Bendix ADB22X air discs, w/ Bendix ABS & traction control

Tires & wheels: Front, Bridgestone 425/65R22.5 M854; rear, Bridgestone 11R22.5 M853, on Alcoa polished aluminum discs

Auxiliary axles: Three Watson & Chalin 10,000-lb. steerable and liftable pushers, one 13,000-lb. Hendrickson swing-down steerable booster

Fuel & DEF tanks: 75-gal. single aluminum & 11-gal. plastic

Body: McNeilus 11.5-cu.-yd. Bridgemaster concrete mixer

The heart of the spec is the 10.8-liter MX-11 diesel, a lighter-weight alternative to the Cummins ISX12 and Paccar MX-13 diesels also offered, by about 400 pounds. Stoneway, a division of Gary Merlino Construction, is a launch customer for the MX-11. Lo Priore liked its promise of good reliability and longevity (its B10 life is projected at 1 million miles, meaning 90 percent of them should still be running at that point with no major repairs), and easy-to-service features. The 430-horsepower rating he chose provides a good power-to-weight ratio for the heavy loads, and a self-shifting transmission greatly reduces drivers’ workloads.

Stoneway tried out two prototype seven-axle T880s with this engine last fall and found the setup worked well, so followed with an order for nine more. The transmission in the truck I rode in back then was an Eaton LL-type UltraShift Plus automated manual gearbox. Driver Dan Leenhouts, my chauffeur for the ride, preferred the UltraShift over traditional manual transmissions, but said an Allison torque-converter automatic “is better for what we do.” That’s what Lo Priore went with for the nine subsequent trucks.

The same Allison is what the demo truck in Ohio had: specifically, a 7-speed 4700RDS (for rough duty series). Most heavy Allisons are 6-speeds, with a 1st gear ratio of 3.51. The 4700’s extra gear is a 7.63 for 1st. From there the ratios are the same, including two overdrive top gears. This turned out to be the nicest heavy-truck automatic I’ve driven lately. It transmitted the engine’s power with no sense of slushiness and was extremely smooth-shifting. Because the truck was empty, the starting gear was 2nd, and the engine cruised at a reasonable 1,400 rpm at 60 mph, with a 4.56 to 1 axle ratio. That was actually a tad slower than the indicated 1,420 rpm at 60 mph that I saw in a T880 dump truck with an automated 11-speed and a “faster” 3.91 axle ratio. Go figure.

The T880 itself is a pleasurable machine to drive, with a ride more comfortable than one would expect from the stiff springs necessary to tote the many pounds expected of it. Excellent visibility all around makes a driving job safer, and the cab feels spacious compared to the older, narrower cab still used on the T800 and W900 series. I drove this mixer over nearby freeways and onto Chillicothe’s streets, testing the truck’s behavior over bumps and its ability to negotiate 90-degree turns. All good. Kenworth’s Swihart rode along, and we talked about the truck’s performance—as a cargo hauler and driver pleaser, and on sales charts.

In the four years since it was introduced, the T880 has risen in popularity among vocational-truck operators to where it now takes 80 percent of the orders that used to go to the venerable T800. That begs the question: How much longer will the “T8” be around?

“As long as enough customers want it,” said Swihart. “There are some who still prefer that rugged cab—though the new cab is every bit as strong—and the truck’s more traditional looks. But they will be fewer as more operators see what the T880 offers and we extend its specifications to more applications.”

We also talked about setback versus forward-set steer axles and which is needed for which state’s weight laws. There are still places where a “bridge truck” means an axle-forward configuration to achieve the maximum-possible wheelbase and allowable weight. California is one of those states where authorities historically have mistrusted lift axles, calling them “cheaters” because wise-guy truckers would reduce suspension pressure to save wear on tires (and never mind that more wear would go to drive- and steer-axles still firmly on the pavement). More important, spreading out weight over widely spaced axles is relatively easy on pavement sections and bridge spans. So from Kenworth, the California bridge truck is the W900S with its set-forward axle and T800-like sloped hood.

When will the newer cab be put on the W900S, and for that matter, the traditionally styled W900 highway conventional? “That’s a good question,” Swihart said. “Would the newer, more modern cab look appropriate on a W900? Would customers of that style of truck like it?” Then why not build a T880 with a set-forward steer axle, like Peterbilt’s Model 567, which comes with a forward-set or rear-set steer axle? “That is what Peterbilt does,” he said, “and we could do that with the T880. But that would run counter to Kenworth’s designation practice,” with T meaning setback and W meaning set-forward. “That will take some more thought.”

By the way, driver Dan Leedhouts liked the new Kenworth T880 so much that he decided to postpone his planned retirement after many years with Stoneway and work for two more years. Fleet executives call that “retention.” And it’s pretty strong testimony, because during my ride last fall Leedhouts talked a lot about his hobby, fishing. He and friends hang out lures and lines in Washington’s rivers and offshore, in Puget Sound and the Pacific, whenever they can. He knows a lot about the creatures: For example, do you know what happens to the bodies of salmon after they swim upriver and spawn? It ain’t pretty. Anyway, with more months of work on the horizon, he’ll have to put up the “Gone Fishin’” sign and hang out one that says, “Still Drivin’.”

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