Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

Test Drive: Oshkosh S-Series Mixer

Precise concrete placement is a traditional feature for this front-discharge mixer, but relatively new is natural gas power.

Tom Berg
Tom BergFormer Senior Contributing Editor
Read Tom's Posts
September 22, 2014
Test Drive: Oshkosh S-Series Mixer

The front-facing barrel and chute on this Oshkosh S-Series allow the driver to place the concrete right where the crew wants it, and front-driving axle helps get it through sand and mud. Here the chute is stowed for travel, with its extensions flipped up.

5 min to read


The front-facing barrel and chute on this Oshkosh S-Series allow the driver to place the concrete right where the crew wants it, and front-driving axle helps get it through sand and mud. Here the chute is stowed for travel, with its extensions flipped up.

In business, time is money, and that’s especially true in concrete hauling and placement. Concrete is perishable: A chemical reaction begins almost as soon as cement is added to aggregates and water, and the batch starts to set. Barrels on mixer trucks therefore get warm, but the rotating motion and the baffles inside keep concrete in a slurry while thoroughly combining the ingredients. Drivers must hurry to work sites and pour the concrete quickly, and exactly where contractors want it.

Ad Loading...

The fastest way to do the hauling and pouring is with a front-discharge mixer, say those who make and sell them. An example is this S-Series, made by Oshkosh Truck Corp. in eastern Wisconsin, where I went to drive it. With a powerful engine and automatic transmission, it accelerates fast and runs down the road smartly. The truck rolls right up to where the concrete is needed and its driver operates the front-facing chute with in-cab controls, moving it exactly to where the crew wants the concrete poured and at just the right rate.

Depending on the job, the contractor can eliminate one worker from his crew, so many request this type of truck for deliveries. They tend to proliferate where they’re introduced, though in some areas producers are sticking with less costly rear-discharge mixers on conventional truck chassis.

Ad Loading...

Like any truck, the S has been greatly improved over the years. The one I drove for this story has a roomy, comfortable cab, good leg room, modern suspended pedals, and a few gauges that tell the driver all he needs to know.

To the right of the steering wheel are handy controls to operate the drum and chute. Greg Steffens, a project engineer, knelt on the fender to my left and showed me how to use them. A lever activates a pair of hydraulic cylinders that unfold the chute, which is long enough for close-in pours. The driver has to get out to hang extensions if the chute needs to reach farther, and of course to clean it out and stow the extras afterwards. Climbing into and out of the cab takes some bending and crab-walking, but gets easy with practice, Steffens said.

A joystick moves the chute left or right and up or down. Push buttons speed or slow the drum to regulate the pour rate. An Allison automatic transmission is standard in the S Series, as it is in all modern front-discharge mixers. The driver punches D or R and feathers the accelerator and brake as required while moving the chute.

When the pour is done, the chute is parked at an angle to the right. It’s important that it not be swung too far or it would extend beyond legal width limits and might collide with trees, poles and other things that line a street. So a rubber bungee cord hangs down from the top of the chute as a marker, Steffens explained. When the right side of the chute touches it, the truck doesn’t exceed 8 feet wide — low-tech but effective.

This truck had the latest in power: a Cummins Westport ISX12 G natural gas engine. Natural gas is not new for Oshkosh and its McNeilus subsidiary over in Minnesota, which between them have built more than 8,000 such trucks since 2008. But this four-axle chassis was the first with two large vertical compressed natural gas tanks mounted to the left- and right-front of the rear engine compartment, instead of four smaller tanks stacked horizontally ahead of the hood. The new configuration saves about 500 pounds and allows easier access to the engine and transmission.

Ad Loading...

There was no concrete in the drum so I couldn’t practice pouring — or placing — it. However, the truck was very drivable, so I released the parking brakes, punched D and off I went. With the gas engine out back, the quietness is almost eerie. I couldn’t hear it idle, and its working growl faded away as road speed increased. Cummins Westport G engines are spark-ignited; a diesel’s compression ignition is more efficient, but produces that characteristic pounding sound. At highway speeds the chassis produced some muted mechanical whirring and tire whine, as well as the slight sound of air rushing past the mirrors and the cab’s front corners. The ride was smooth, even with a stiff front suspension and the blocky 445-series tires.

Acceleration was brisk as I departed and headed for nearby Wisconsin 26, a wide two-laner, and turned south, immediately encountering some memories. As a TV newsman many years before, I sometimes barreled north on this highway in a company car at up to 100 mph to get news film to the station in Green Bay in time for the 6 o’clock broadcast. This day I cruised at 55 to 65 mph, where the Cummins spun at 1,600 to 1,800 rpm — not wound out, but far faster than today’s low-revving diesels in road tractors.

This was the highest-rated ISX12 G, and with 400 horses, it had plenty of go-power. If it was consuming fuel at a fair rate, so what? Natural gas is much cheaper than diesel, so savings will help pay off the premium price for the natural gas fuel system.

I turned right on a county road and followed it west and north a ways. I stopped and backed into a deserted intersection to reverse course and return the way I came. Maneuvering was easy and the view out the cab’s windows and through its mirrors was fine, so I never used this truck’s rear-view camera with its mini TV screen above the windshield.

I meandered along other roads and onto city streets, and at one point did a couple of circles on a gravel parking lot. The wide tires limit wheel cut and make the turning circle a bit big, but it seemed to corner better than a conventional with a forward-set steer axle and wide tires. With Sheppard power steering, the truck didn’t require much effort to turn, even while crawling.

Ad Loading...

Upon my return, I parked it in front of the building. Recent rain had muddied a section of the back lot, where a line of new mixer and military trucks awaited transport to customers. I was tempted to jump back into the S and put its front-driving axle and lockable differentials on the rear tandem to a test, but didn’t have the heart to get the shiny white rig dirty. Besides, I’ve seen them move through mud and know they’re up to it. That’s part of what makes this a seriously mobile and productive truck.

Subscribe to Our Newsletter

More Fuel Smarts

A GP Transco tractor-trailer crosses a bridge over a river, with trailer side skirts visible beneath the white trailer.
Fuel Smarts•by Deborah Lockridge•October 27, 2026

How GP Transco Builds Fuel Savings a Fraction at a Time

Aerodynamic specs, solar panels, and driver incentives help GP Transco turn small efficiency gains into savings it can reinvest in its people.

Read More →
Man on large stage with American Trucking Associations logo in the background and large screen displays of distillate stocks.
Fuel Smarts•by Deborah Lockridge•October 20, 2026

Trucking’s Diesel Squeeze Isn’t Letting Up

With diesel topping $6 a gallon nationally, ATA's Bob Costello explains why fleets should prepare for continued pressure at the pump.

Read More →
Computer rendering showing airflow around a trailer’s tandem wheels equipped with FlowBelow AeroSlider fairings and wheel covers.
Fuel Smarts•by Deborah Lockridge•October 18, 2026

FlowBelow Redesigns Trailer AeroSlider to Cut Fuel Use

The lighter trailer aerodynamic system installs in less than 45 minutes, according to the company, with potential payback in under a year depending on fuel prices and trailer mileage.

Read More →
Ad Loading...
Illustration with oil wells, dollar bills, and a diesel fuel pump
Fuel Smarts•by Deborah Lockridge•October 14, 2026

Why Diesel Price Relief Efforts May Fall Short

Diesel prices have eased from September’s record high, but doubts about additional Russian supply and limits on dyed-diesel tax relief mean trucking fleets still face expensive fuel. And prices could go higher.

Read More →
Video thumbnail with text: Fuel -- small gains, big savings.
Fuel Smarts•October 12, 2026

Why Small Fuel Savings Matter in Trucking

Can better fuel economy help pay for driver raises? In this podcast, GP Transco explains how small efficiency gains create room to reinvest in its people.

Read More →
Youtube thumbnail showing two people with a truck and the word "fuel" behind them, the HDT Talks Trucking logo, and the words "Small Gains. Big Savings."
Fuel Smarts•by Deborah Lockridge•October 12, 2026

How GP Transco Cuts Trucking Fuel Costs, a Tenth of a Gallon at a Time

What’s another tenth of a mile per gallon worth? GP Transco shares how equipment upgrades and driver coaching turn small gains into meaningful fuel savings.

Read More →
Ad Loading...
Photo of electric OrangeEV terminal tractor with a Lazer Logistics trailer
Equipment•by Staff•October 6, 2026

Electric Yard Tractors Move Beyond Pilots

Operating-cost savings have overtaken sustainability goals as the leading reason surveyed fleets are adopting battery-electric terminal tractors, according to new NACFE research.

Read More →
Illustration of map with GPS markers overlaid with Geotab fleet card and a fuel pump nozzle
Fuel Smarts•by Staff•October 2, 2026

Geotab Links Fleet Card to Vehicle Data

The new card combines fuel discounts with telematics-based purchase controls. Geotab’s analysis also points to potential savings from choosing lower-priced fuel stops.

Read More →
White Tesla Semi electric truck on display on a show floor
Equipment•by Staff•September 30, 2026

Fleet Economics Shape Electric Truck Outlook

ACT Research expects costs, charging infrastructure, and technology improvements to drive zero-emission commercial vehicle adoption as federal regulations and incentives retreat.

Read More →
Ad Loading...
Male truck driver in flannel shirt by truck using his smartphone
Fuel Smarts•by News/Media Release•September 23, 2026

Wex Adds Cardless Fuel Payments for Over-the-Road Customers

A new fuel card feature for Wex customers offers convenience and security.

Read More →