Truck Loading &
Center of Gravity Calculator
Ensure legal compliance and safety by calculating your truck's axle load distribution and Center of Gravity (CoG) in seconds.
Understanding Truck Loading & Axle Weights
Calculating the correct distribution of cargo weight is essential for any logistics operation. Whether you are running a single rigid truck or a large fleet, understanding how weight impacts your vehicle's Center of Gravity (CoG) and axle loads is key to safety and profitability.
Why is Axle Load Calculation Important?
- Avoiding Fines: Road authorities enforce strict weight limits per axle (e.g., 9000kg for a front steer axle). Exceeding these limits, even if the total truck weight is under the Gross Vehicle Mass (GVM), can result in significant fines.
- Steering & Handling: If the front axle is too light (due to too much weight at the rear), steering becomes vague and dangerous. If it's too heavy, steering becomes heavy and unresponsive.
- Vehicle Maintenance: Overloading specific axles causes rapid uneven tire wear, suspension failure, and can even crack the truck chassis over time.
What is Center of Gravity (CoG)?
The Center of Gravity is the single point where all the mass of the truck and its load can be considered to concentrate.
Types of CoG in Transport
- Longitudinal CoG: Positioned along the length of the truck. This determines the weight split between front and rear axles.
- Transverse CoG: Positioned side-to-side. This affects stability when cornering.
- Vertical CoG: The height of the load. A higher CoG increases the risk of rollover.
This calculator focuses primarily on the Longitudinal CoG to ensure your legal axle weight limits are respected.
How to Calculate Axle Load Distribution
The calculation is based on the principle of moments. Here is the simplified process used by our calculator:
- Determine Moments: For every item of cargo, we multiply its weight by its distance from the front axle. This gives the "moment" of that item.
- Sum Moments: We add up all the moments from the cargo and the empty truck body.
- Calculate Center: Divide the total moment by the total weight to find the new Center of Gravity.
- Split Weight: We use the position of this CoG relative to the wheelbase to determine how much weight rests on the front versus the rear axle.
Frequently Asked Questions
What happens if I overload the front axle?
Overloading the front axle can cause damage to steering components, front suspension, and tires. Crucially, it makes the truck heavier to steer and can lead to understeer in corners, which is a major safety hazard.
Does this calculator work for semi-trailers?
This specific tool is designed for strict rigid trucks (2-axle configurations). For semi-trailers, you need to calculate the Kingpin load and how it distributes onto the tractor unit's axles, which requires a more complex multi-unit calculation.
How do I find the center of gravity of my cargo?
For uniform objects (like a pallet of bricks), the CoG is usually in the geometric center. For irregular items (like a machine part), you may need to consult the manufacturer's technical drawings or use a crane scale to find the balance point.
What is the "Wheelbase"?
The wheelbase is the horizontal distance between the center of the front axle and the center of the rear axle. On multi-axle trucks (e.g., 6x4), it is typically measured to the center of the rear bogie (axle group), though regulations may vary.
Why is the tare weight split between axles?
An empty truck is not perfectly balanced. The engine, cab, and fuel tanks usually sit over the front axle, making it heavier when empty. Knowing the "tare" (empty) weight of each axle is the starting point for accurate loading calculations.
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