Navistar Power On a Phoenix Chassis

May 31, 2012

Navistar International has one of the widest product lineups in the business, including heavy severe-service conventional-cab models that can carry rear-discharge concrete mixer bodies. A few years ago, executives took the company deeper into concrete by buying Continental Mixer, then decided to enter the specialized front-discharge market with a new partner, Indiana Phoenix.

Navistar International has one of the widest product lineups in the business, including heavy severe-service conventional-cab models that can carry rear-discharge concrete mixer bodies. A few years ago, executives took the company deeper into concrete by buying Continental Mixer, then decided to enter the specialized front-discharge market with a new partner, Indiana Phoenix.

Continental Front Discharge Specifications

  • Truck: Continental Front Discharge mixer, chassis and cab by Indiana Phoenix, 6 x 8 w/ front-driving axle and single pusher lift axle, GVW 80,000 lb. (but legally less due to state limits)
  • Engine: Navistar MaxxForce 13, 12.4 liters (758 cubic inches), two-stage turbocharged, intercooled and aftercooled, 430 hp @ 1,800 rpm, 1,550 lb.-ft. @ 1,000 rpm
  • Transmission: Allison 4500RDS, 6-speed automatic
  • Front driving axle: 23,000-lb. Meritor MX23 w/ 5.38 ratio, on taperleafs
  • Transfer case: Cushman single-speed
  • Rear tandem: 46,000-lb. Meritor 46-160 w/ locking diffs and 5.38 ratio, on Hendrickson Primaax mechanical
  • Wheelbase: 185 inches
  • Lift axle & suspension: 20,000-lb. Hendrickson HLM/E non-steering pusher
  • Brakes: Meritor S-cam w/ Meritor Wabco ABS
  • Tires & wheels: 445/65R22.5 Goodyear G178L on aluminum discs
  • Body: 11-yard Continental Front Discharge

The result is this copper-colored truck displayed at trade shows and recently made available for a drive by yours truly. It’s the first of its kind, but the three parties hope that many more will follow. To be sure, only about 8,000 new trucks like this sell in a good year, and the last one predated the Great Recession. Right now the market is stagnant, with mostly glider-kitted models selling, but history says things will revive. 

The truck is branded as a Continental and will be sold by select distributors who are also International truck dealers. They’ll provide service support for the entire vehicle, simplifying life for operators. Basically, this is a Phoenix with another name and engine, and Indiana Phoenix has long experience with such vehicles. 

For now all the parties are getting accustomed to the new venture, which includes verifying various aspects of the truck’s performance. That includes making sure the MaxxForce 13 engine can be cooled in this rear-mounted position, which requires a large radiator and effective fan-drive mechanism, and that the drum can mix and deliver the stiffest concrete batches conceivable.

Overseeing this is Continental’s Greg Vickers, a veteran of the truck and ready mix industries (including a stint at the National Ready Mixed Concrete Association), who said he has seen the engine thrashed on a dyno in the cooling tests and the drum laboring to deliver thick low-slump loads. The goal is official certification by the Truck Mixer Manufacturers Association to satisfy potential buyers. He has driven this truck more than a few miles and was ready with instructions when we met at the Phoenix factory early on a chilly but sunny spring morning.

“There’s a learning curve to driving these,” Vickers said, “but it’s not long—about 30 minutes. You have to get used to being in the middle of the lane, not like a conventional mixer truck where you’re off to one side.” OK, no problem, because I’d driven front-discharge mixers before. And I can add that sitting squarely in the middle of the truck is advantageous because there’s no blind side. With plenty of glass in the Panavision cab, I could easily see in all directions.

My learning curve involved figuring out the most graceful way to get into the cab. The chassis is high, so I had to climb two steps up and move left onto a platform adjacent to the cab. The cab is roomy but sits low, so it’s something like squeezing into a sports car. Vickers suggested backing in, but I found that crouching down and moving sideways into the cab, carefully placing my feet as I went, worked for me.

Once in the seat, everything fell easily to hand. The steering wheel was well placed, and gauges and switches were on a small instrument panel directly in front of me. Well labeled toggle switches included a few that operated the transfer case and lockout for the interaxle differential; because I stayed on pavement, I left those alone and was content with sending power to the tandem only. The heater and air conditioning controls were down in one corner, with slider levers for temperature and a rotary switch for the fan. Outside temps were in the low 40s, but there was plenty of heat available, though I had a little trouble finding a comfortable setting.

A joystick to the right operated the drum and chute. Vickers showed me which way to move it for different functions. A driver can swing the chute left or right and extend it with an optional hydraulic foldover chute, after getting out and hanging extensions onto the main section. The stick had a smooth feel, and soon I felt like my hand was directly linked to the rig’s hydraulic system. A slump meter is among the gauges on the panel, and a lever on the floor to the left of the seat allows the driver to add water to the mix in the drum.

At a job site, the driver moves the truck right up to the pour point, sets up the chute, then positions it exactly where the contractor’s crew wants it. He uses a foot pedal or the joystick to send out the concrete at the rate the crew wants. He repositions the chute with the joystick and by moving the truck forward and backward. That’s fairly easy with the Allison automatic transmission, whose push-button selector was also to the right. Early front-discharge mixers had manual transmissions with clutch pedals, and drivers had their hands and feet full trying to do everything.

Front-discharge, rear-engine mixers are common in certain markets but rare or absent in many others. Contractors like them because the trucks roll right up to the work area, pour concrete fast and, because the driver controls the chute, they eliminate one man from a crew. Pours usually go fast, and a truck can sometimes deliver an extra load per day. But they’re expensive—about a quarter-million dollars for this one—and cost more to operate and maintain than conventional, rear-discharge mixer trucks. Once introduced to a market, though, contractors see what they can do and demand more, so front-discharge machines tend to multiply.

So, how’s it on the road? Nicer than you might think if you’ve never driven one, and better than I recall from previous drives of this truck type. The MaxxForce 13 engine was powerful and, being more than 30 feet to the rear, was very quiet. In that respect it’s like driving a rear-engine bus or motor home; you can hear the engine enough to judge what it’s doing, but it’s faint and the cab is pleasantly quiet. The engine’s 430 horses—compared to the usual 350 or 375 horsepower in this application—move the truck at a fast clip and will be plenty strong enough to propel the truck and nine or more yards of concrete.

Out on the highway, the engine spun at about 1,600 rpm at 60 mph, just about right for a vocational application and typical of a six-speed Allison automatic. While accelerating, revs rose to 1,700 or 1,800 and fell down when the transmission smoothly upshifted and its torque converter locked or unlocked. With no load in the drum, acceleration was more than enough to keep up with traffic. And the truck turned sharper than I expected, even with the 445-series tires and the hefty front driving axle. With the windows cranked up, there was little wind noise—surprising, given the cab’s square edges and all the mixer appendages hanging nearby. At 50 mph the cab began vibrating; I could feel it in the steering wheel but not in the air suspended seat. Vickers said the vibes come from the block-treaded wide-single tires. Some operators use smoother steer-axle tires with duals on the tandem to eliminate this.

To sum up, users of this special truck type now have something more to consider if they go to market for all-new equipment. That might not be for a while, but whenever it comes, buyers might be pleased with what they see in this Navistar-Continental-Phoenix product.