Carr Bros. adds up fuel savings from revolution-optimizing mixer drum control

88 Carri 400

89 Carriia 400

For nearly a decade, the SMART Drum control system has demonstrated performance and potential in four areas or functions affecting a ready mixed producer’s bottom line: drum wear and service life; improved safety through vehicle stability; concrete quality as measured by mix consistency and stabilized heat of hydration, both due to optimized agitation; and, as the Carr Bros. study demonstrates, fuel economy attributable to controlled drum speeds and avoidance of unnecessary revolutions.
89 Carriib 400

With founding-family members at the helm since 1892, Cleveland-based Carr Bros. has demonstrated a capacity to adapt to the changing nature of the concrete business, including current efforts to reduce fuel consumption. The producer recently worked with Schwing America to identify prospective savings using the manufacturer’s SMART Drum technology. The electronic wireless control system nets longer drum life, higher quality concrete, improved safety conditions, and reduced fuel consumption when measured against standard mixer trucks.

“Fuel is an uncontrollable cost,” affirms Mike Carr, fifth-generation owner. “And when the price is high, diesel costs will eat my lunch. When diesel is under two dollars a gallon it’s great, but when it’s four dollars or over per gallon, it really hurts us.”

Removing all other variables by using two identical trucks, he and his team used the SMART Drum control as the independent variable to study precise fuel consumption. “Conditions were ideal,” notes Schwing Regional Sales Manager Andy Conway. “The only difference between the two trucks was the drum. The trucks were identical—same make, model, engine, transmission. Both mixers were mounted on the same chassis, going to the same job, traveling the same route, driven by seasoned drivers with more than 30 years of experience, and [had] minimal idle time on the job site.”

To compare the SMART Drum-equipped mixer against its control companion, both vehicles’ fuel tanks were topped off before traveling to the job site. The drivers were responsible for recording the number of yards of concrete loaded and unloaded, drum revolutions when leaving the plant and arriving at the job site, estimated travel speed and total miles.

“After the job was complete, one driver added 29 gallons of fuel while the other added 34 gallons,” says Schwing National Sales Manager Charlie Schumacher. “The study showed us that running SMART Drum in ideal conditions can save up to 14.7 percent of fuel consumed. Conservatively, we can say that businesses can save $4,000 to $5,000 per year for each truck using this technology.”

Adding fuel savings to a drum that already offers longer service life and higher quality concrete is a tremendous bonus, according to Carr. “The fuel savings is outstanding, and I hadn’t considered just how valuable the fuel costs would prove to be before we conducted the study,” he affirms. “The savings on drum wear and the higher quality concrete are valuable benefits for us, and adding the fuel savings creates the perfect trifecta.”


Designed and patented by Schwing America in 2007 and now in its third generation version, (Schwing Mixer Automatic Revolution Technology) SMART Drum uses wireless technology for prolonging drum life, maintaining concrete quality, and reducing fuel consumption.

“In all mixer drums, there is a direct relationship between engine and drum rpm,” Conway observes. “With SMART Drum, the system has a defined threshold, and once the vehicle reaches a certain speed, a hydraulic pump output goes into a constant flow and it doesn’t draw any more horsepower from the engine. This process puts 35–40 horsepower back into the engine, which generates the fuel savings and efficiencies.”

Maintaining the drum at lower constant speeds saves approximately 100,000 revolutions per year, which equates to huge dollar savings in drum wear and reduced fuel consumption. Lower drum speed provides a number of ancillary benefits, Schumacher affirms, noting, “The SMART Drum technology enhances the quality of the concrete. By not adding extra rotation to the mixer drum, the concrete is more consistent and the heat of hydration is constant, which makes the mixer deliver a higher quality product. By providing a constant center of gravity that does not shift on the truck even though the drum is spinning, the truck is therefore more stable, and ultimately safer.”


With just under 50 employees, Carr Bros. exhibits a family-owned feel and maintains solid business relationships with Schwing and the concrete and construction community throughout Ohio. Mike Carr envisions implementing additional SMART Drums as existing barrels on his 30-truck fleet begin to reach the end of their service life. “It can be a big hit to the overall budget when we wear out a drum,” he says. “The SMART [control] adds significantly longer life to the drum, which helps us out on the budget.”

Learning the results from the fuel study added yet another benefit to Schwing’s advanced drum technology. “Initially, the two most important benefits to me were the drum life and the quality of concrete,” notes Carr. “Now that we know the significant fuel savings the drum provides, all of these features provide a huge impact on our bottom line and compelling reasons to continue purchasing the advanced drum control systems.”

The SMART Drum control system and mixer truck series will be part of Schwing America’s 2016 World of Concrete exhibit fronting the Las Vegas Convention Center Central Hall, booth C5126.


With SMART Drum

Without SMART Drum

Percentage of Savings

Types of roads



Estimated speed of travel

50 mph

50 mph

Total miles traveled

25.5 per load

25.5 per load

Total number of loads



Average drum revs
per completed load cycle




Gallons of fuel used