For the past 25 years, I have conducted an annual operating cost survey and a separate fleet maintenance survey. And, each year, industry data shows that the No. 1 root cause of unscheduled truck maintenance expense is the consequences of overloading. This is a chronic problem for fleets and there are several factors causing it. A key reason is that companies seek to lower acquisition costs by selecting lower-GVW trucks. Although this strategy saves money on the front end, the inevitable overloading increases operating costs on the back end. The second reason for spec’ing lower-GVW trucks is to avoid DOT regulations, which require drivers to have a commercial driver’s license (CDL) to operate vehicles greater than 26,001-pounds GVW. With the ongoing shortage of drivers, those with CDLs are difficult to find, and when found, are expensive to hire. The easy way to circumvent this problem is to spec a truck with a lower GVW rating beneath the CDL threshold.
Determining the correct vehicle size for the intended payload often requires a judgment call as to how much over-capacity to build into the payload capacity of the vehicle when spec’ing its requirements. Spec’ing the truck to the minimum necessary payload rating (by basing it on an average load or looking at only today’s business needs instead of trying to anticipate future needs) means the vehicle will be operating at peak capacity most of the time, which may compromise safety and the length of its service life. Spec’ing for an average payload means that the vehicle will sometimes be overloaded, resulting in greater than normal wear-and-tear, higher maintenance costs, and reduced fuel economy.
One of the best ways to determine if your vehicles are being overloaded is to go into the field and assess vehicle usage while performing a fleet application. There are several ways to determine overloading: a sagging rear-end, irregular tire wear, premature brake wear, and loose unresponsive suspension and steering. Drivers can be requesting the wrong vehicle for the application and all the while the fleet manager thinks everything is fine. Overloading creates an unsafe vehicle and increases liability exposure in the event of an accident. Consider the following:
- Emergency handling capability of an overloaded vehicle is reduced, which may result in an accident.
- Braking distance increases, which can cause drivers to misjudge stopping distances.
- Tire failure rates are higher because tires run hotter.
- Plus, roadside weight checks (if applicable) could result in overloading fines and possible vehicle impoundment until the problem is corrected.
It is also advisable to avoid modifying a vehicle to accommodate a heavier payload, such as changing tire sizes, adding spring kits, air shocks, heavy-duty brakes, and anti-sway kits. When you modify a vehicle, you can create an unsafe situation by changing the integrity of the vehicle. In addition, this may affect the new-vehicle warranty and increase liability exposure if there is an accident.
An overloaded truck is costly to maintain and operate. When a truck is overloaded, the truck’s operating performance will be strained, accelerating wear-and-tear on brakes and other components. For instance, tire failure rates are higher because tires run hotter due to the increased load.
Another prevalent problem is axle overloading. Even though a vehicle’s payload is within OEM limits, the vehicle may still be overloaded on one of its axles. It is possible that a front or rear axle is overloaded with only a portion of the maximum payload on the truck. Load distribution is the key to avoiding axle overloading. This can cause premature wear-and-tear on tires and suspension components. It also affects vehicle driving characteristics.
Overloading also increases operating expenses. There’s a direct correlation between vehicle weight and fuel consumption. Every pound of extra weight requires an engine to work harder, increasing fuel consumption. For instance, an extra 100 lbs. in vehicle weight can reduce mpg up to 2%. In addition, every pound deleted from curb weight is converted into revenue-generating payload.
Not only is an overloaded truck in violation of numerous state and federal regulations, it is unsafe to operate. As statistics show, year-after-year, overloaded trucks are one of the leading causes of truck-related accidents. The reason is that payloads that are overweight or unbalanced increase the likelihood a driver may lose control of the vehicle.
You can solve the problem of overloading on the front-end by spec'ing the appropriate GVW truck to fulfill the fleet application or on the back-end by ensuring employees operate the vehicles within the OEM's payload parameter.
Let me know what you think.