Calculators · Towing and loads

Axle load, centre of gravity and weight transfer calculator

Where a load sits matters as much as how heavy it is. A load behind the rear axle adds more than its own weight to that axle and lifts weight off the front, which affects steering, braking and axle ratings. These calculators show how a load changes each axle’s weight, locate a vehicle’s centre of gravity from axle weights, and estimate how much weight moves between axles under braking or acceleration.

Axle loads after adding a load

Splits a load between the axles by lever principle, using its distance behind the front axle. A distance greater than the wheelbase means the load is behind the rear axle, which unloads the front axle — a negative front change.

Results
New front axle weight—Compare with the front gross axle weight rating.
New rear axle weight—Compare with the rear gross axle weight rating.
Front share of total—%Front axle weight as a percentage of the total.

Formula
rear added = load × position / wheelbase
front added = load − rear added

Centre of gravity from axle weights

Locates the centre of gravity along the vehicle from the weight on each axle, measured on scales. Its position explains a vehicle’s balance: nearer the front means more understeer and better traction for front-wheel drive.

Results
Centre of gravity behind front axle—Horizontal distance from the front axle centre.
Weight distribution (front)—%Share of total weight on the front axle.

Formula
x = wheelbase × rear / (front + rear)

Weight transfer under braking or acceleration

When a vehicle brakes, weight moves onto the front axle; when it accelerates, onto the rear. The amount depends on deceleration, centre-of-gravity height and wheelbase — tall vehicles with short wheelbases transfer the most.

Results
Weight transferred—Load moved from one axle to the other, expressed as mass.
Load transferred—The same transfer as a force.

Formula
ΔW = m × a × h / wheelbase

Worked example: loading a van

  1. A van with a 3.0 m wheelbase weighs 1,000 kg front and 800 kg rear.
  2. A 500 kg load 2.4 m behind the front axle adds 500 × 2.4 / 3.0 = 400 kg to the rear and 100 kg to the front.
  3. A 300 kg load hung 4.0 m behind the front axle — 1 m behind the rear — adds 400 kg to the rear and removes 100 kg from the front.
  4. Braking a 1,500 kg car at 0.8 g with a 550 mm centre of gravity moves about 244 kg onto the front axle.

Typical front weight distribution

LayoutFront share
Front-engine, front-wheel driveabout 58 – 64%
Front-engine, rear-wheel driveabout 50 – 55%
Mid-engine sports carabout 40 – 45%
Rear-engineabout 38 – 42%
Empty pickup truckabout 55 – 60%

Related

About these results

Results are theoretical estimates from standard engineering formulas. Real-world figures depend on conditions these formulas do not capture. Always follow the manufacturer's specifications for maintenance, loading and safety decisions.