Simply put, a truck requires energy to move along and overcome resistance — mechanical, air and rolling — to forward motion. The truck’s engine converts the energy stored in fuelinto mechanical energy used to drive the truck. Some of this work energy is lost in the engine, drivetrain, accessories, wheel bearings, and so on, through mechanical resistance.

Air resistance is caused by the movement of a truck through the air. The greater the speed of the truck and the less aerodynamic its shape, the greater the air resistance. Environmental factors, such as wind and weather, also impact “aerodynamic drag.”

Rolling resistance is caused by the interaction of the tires and the road surface. The amount of rolling resistance depends on the weight and speed of the truck, type of road surface and the design, tread pattern, inflation pressure and condition of the truck’s tires.

There are a variety of factors that impact fuel economy because of their influence on resistance. These include:

Vehicle: The more aerodynamically sleek the design, the less the air resistance. Consider using aerodynamic treatments such as chassis and roof fairings, cab extenders, aerodynamic mirrors and moving equipment out of the air stream.
Operation and application: Loads, speed, routes, traffic, terrain, road surfaces, empty miles and weather all affect fuel consumption. Consider using software programs to assist with boosting fuel economy, as well as productivity and efficiency, through improved inbound/outbound planning, computerized mapping and route optimization, detailed driving directions, and so forth. Telematics can be used to provide driver and vehicle utilization and productivity data. Digital fuel consumption gauges can be used to provide the driver with real-time feedback on fuel economy.

Maintenance practices: The better a truck is maintained, the more efficiently it will operate. That translates into improved fuel mileage and more uptime.

Tires: Tire selection impacts a vehicle’s overall fuel performance, and therefore, should be application specific. Tread depth and design, construction, size, inflation pressure and condition each have an effect on rolling resistance. It is always advisable to consult with a truck tire specialist before making tire purchases, whether new or retreaded tires.

The single most critical factor for getting the most out of tires is to maintain proper inflation pressure for a given tire size and load. Because an improperly inflated tire doesn’t roll as smoothly or as easily as it was designed to, rolling resistance and wear is increased and fuel economy is adversely impacted, as is handling, traction, braking and load carrying capability.

Drivers: No matter how advanced fuel-saving devices may be, they will not achieve optimum results unless they are used with sensible driving practices. These include starting at the slowest engine speed that will move the load; using the minimum rpm, minimum power and fewest shifts necessary when accelerating; running the engine in its peak torque range; using cruise control; using an engine brake; minimizing idling; and accelerating or decelerating well in advance of a stop or a need to speed up.

Excessive vehicle speed has the biggest impact on reducing fuel mileage. Industry studies have found that for every one mile per hour increase in speed over 55 mph, there is a 2 percent loss in miles per gallon. At the same time, higher speeds also increase engine, vehicle and tire wear, leading to higher maintenance costs.

The ideal time to start saving fuel is at equipment acquisition. First, decide upon your fuel economy expectations and requirements for your vehicles. Next, review your current and previous equipment specs to see which have been effective in maximizing miles per gallon. Then, visit with vehicle and component manufacturers to go over this material and to learn about the latest advances and new products and components for fuel economy.

Knowing how to squeeze more miles from each tank of fuel will help reduce operating costs and improve your profitability.

 Driver skills

 Speed

 Electronic vs. mechanical engines

 Rib tires in every wheel position

 Idling time

 Roof fairing vs. flat roof

David Kolman is a veteran truck communicator, keynote speaker and long-haul trucker. Commissioned as an Honorary Colonel on the Kentucky governor’s staff for his work promoting traffic safety, he actively participates in trade associations and reports news and information about the trucking industry for broadcasting and print media.

DaimlerChrysler and Freightliner Market Development have teamed to offer MileMinder, a used-truck contract maintenance program with a guaranteed cost-per-mile agreement. The maintenance package includes all mechanical repairs, preventive maintenance, tire repairs and replacement and roadside services. The program, available for leased or purchased vehicles financed through DaimlerChrysler Services Truck Finance, is offered through participating SelecTrucks Centers and Freightliner, Sterling and Western Star dealers.

Hendrickson has introduced its HTB rear air suspension, “a premium, improved-riding alternative to industry standard suspensions” for Class 8 trucks. A low-maintenance, lightweight, non-torque reactive suspension, it is said to be the lightest suspension in its class at 570 pounds including axle brackets, which saves up to 257 pounds of weight over industry-standard 40,000-pound suspensions.

Peterbilt is making detailed truck schematics and parts lists available through the Internet with its TruckCare Web ECAT (electronic catalog). Replacing the CD-ROM version, Web ECAT cross references a truck’s original chassis record with the PACCAR Parts catalog. Users can search and identify parts by keyword, part number and interactive visual diagrams. Additionally, wiring and air piping diagrams, as well as alternate part selections if the original part is no longer produced, are available.

Roadranger has a new four-disk CD set that neatly packages more than 400 Dana and Eaton product and service documents, providing a comprehensive Roadranger product library. The CD set includes such key information as driver training, lubrication tips, troubleshooting guidelines, illustrated parts lists and warranty information. Components and systems that are featured include axles, brakes, clutches, driveshafts, trailer suspensions, tire management products, manual and automated transmissions, service tools and collision warning systems.