• Reducing the weight of a vehicle can improve its mileage, but carriers should be sure that any modifications can still support the work a vehicle is meant to do.

Another option to improve fuel mileage is to reduce the weight of the vehicle. There are several spec’ing options that can accomplish this, including:

• Lightweight frame and body materials. When spec’ing the vehicle, carriers should assess the use of lightweight frame and body materials (aluminum, plastic, fiberglass, composite materials, etc.). Most manufacturers offer vehicle models that use lightweight materials to lower the vehicle weight. When considering this option, carriers should consider if the lightweight model vehicle is going to be strong enough to do the job the vehicle is designated for.
• Vehicle size. Another consideration with the frame and body is size. Drivers and fleet managers may want big vehicles (whether it is a bus or a truck), but they need to consider if a smaller vehicle would make more sense. The more the vehicle weighs, the lower the fuel mileage.
• Lightweight axle components. The main axle component that can be lightened up (besides the axles themselves) is the wheel assembly. This can be lightened by using aluminum rims rather than steel, or by switching to a “super single” configuration in place of duals. Super singles have several advantages when it comes to fuel mileage (improved rolling resistance, lighter), but come with the disadvantage that one low tire can stop the vehicle.
• Fuel capacity. The more fuel the vehicle carries, the more weight it is carrying. Excessive amounts of fuel (there are truck-tractors built that can carry 400 gallons of fuel) do nothing other than add unnecessary weight to the vehicle. Correct spec’ing normally calls for the vehicle to carry a maximum of one workday’s worth of fuel.