Cargo that rides high raises the center of gravity, which makes the vehicle easier to roll over in curves and on ramps even when its weight is within the legal limit. Keep the heaviest freight low and spread the weight evenly.
GVW counts everything on a single vehicle at once: the vehicle itself plus whatever load is on it. Weighing the empty vehicle or the cargo by itself gives only part of that total.
Dry bulk tanks carry their load high, and the contents can shift, so they tip over more easily on curves and in sudden maneuvers. Hanging meat is actually an unstable load with a high center of gravity, and overweight loads need special permits whatever the time of day.
The driver is responsible for the cargo no matter what it is, so the load and its tie-downs should be inspected again at intervals during the trip, including after every rest stop. This catches shifting freight or loosened securement before it causes a problem.
Each state sets maximum weights for vehicles, combinations, and axles, and drivers must keep their loads within them. A legal weight can still be too heavy for bad weather or mountain grades, and the driver is responsible for an overload even when someone else did the loading.
Tire load is the rating that tells you the most weight a tire can safely carry when it is inflated to the stated pressure, and it is marked on the tire's sidewall. Loading a tire beyond that rating can cause it to fail.
Tie-downs anchor the load to the vehicle so it cannot move, slide or fall off when you brake, turn or hit bumps. Use enough of them for the size and weight of the cargo.
A bridge formula ties the weight axles may carry to how far apart they are. When axles are bunched close together, their load presses on a short stretch of road or bridge, so the allowed maximum is lower, which protects bridges and pavement from overloading.
The basic guideline is one tie-down for every 10 feet of cargo length, and any load that can shift needs at least two, however short it is. Spacing them farther apart leaves parts of the load free to move.
Drive wheels need enough weight pressing them onto the road to grip; with too little, they can spin or slide, especially on wet, snowy, or icy pavement. Arrange the load so each axle carries its proper share.
Shifting too much weight toward the rear leaves the front axle under-loaded. The steering tires then press only lightly on the road, so they grip poorly and the driver may not be able to steer safely.
Weight piled on one side shifts the center of gravity toward that side, so the trailer can tip over more easily, especially on curves and ramps or during a quick lane change. Spreading the load evenly between the left and right keeps the vehicle stable.
Stops during a trip are the time to confirm that the load and its tie-downs have not shifted or loosened and to check whether any tires or brakes are running too hot. Both checks belong in a proper en route inspection.
Overloading the steering axle makes the wheel hard to turn and can damage the axle and its tires. Poor steering traction comes from having too little weight on that axle, not too much.
Excess weight makes a vehicle harder to steer, slower to stop, and harder to keep at a safe speed on hills. The legal weight limits are a different matter: they are fixed by law and stay the same no matter how a vehicle is loaded.
Weight spread evenly between the left and right sides and between the front and rear keeps a vehicle stable and easy to control. Too much weight up front can make steering hard, while too much at the back can leave the steering axle too light to steer safely.
Any load that might move needs no fewer than two tie-downs, even if it is small, and longer loads need more, with at least one for each 10 feet of cargo.
Covers keep loose cargo from blowing or spilling onto the road, where it could hurt people, and they also shield the load from the weather. Because spill protection is a safety matter, many states require it, so every statement listed is true.
Hanging meat and live animals can swing or shift toward the outside of a curve and push the vehicle toward a rollover, so take curves slowly and smoothly. Oversize loads always require special permits, and a liquid tank must never be filled completely because the liquid needs room to expand.
A load that is not tied down can slide, roll or fall from the vehicle, so tie-downs are used to lock it in position. Cargo should have enough of them for its size, and even a small item needs at least two.
GVW is what a single vehicle really weighs, counting the cargo, fuel, and people on board. The manufacturer's maximum rating is the GVWR, and a power unit weighed together with its trailers and their cargo gives the gross combination weight (GCW).
Tip Keep the two apart: GVW is the weight a scale reads right now, and GVWR is the upper limit the manufacturer allows.
Every question in this set has its own page with the correct answer and an explanation.
