Weight Transfer Calculator (Braking & Acceleration Load Transfer)
Calculate longitudinal weight transfer under braking or acceleration — ΔW = W × a × h ÷ L — and the resulting front and rear axle loads from vehicle weight, CG height, wheelbase and g-force.
How it works
ΔW = W × a × h ÷ L · W = vehicle weight, a = deceleration or acceleration in g, h = centre-of-gravity height, L = wheelbase · braking: front = static front + ΔW, rear = static rear − ΔW · accelerating: the reverse
When a car brakes, inertia acting at the centre of gravity — which sits above the road — tries to pitch the body forward, and the front tyres take extra load while the rear tyres are unloaded. The amount transferred depends only on the deceleration and on the ratio of CG height to wheelbase; springs and dampers change how quickly it happens, not how much. This is why front brakes do most of the stopping, why a car squats when accelerating, and why tall, short vehicles pitch more.
Worked example
A 1,500 kg car with 55% of its weight on the front axle, a CG 0.55 m high and a 2.7 m wheelbase brakes at 0.8 g: ΔW = 1,500 × 0.8 × 0.55 ÷ 2.7 = 244 kg. The front axle load rises from 825 kg to 1,069 kg (71.3% of the weight) and the rear drops from 675 kg to 431 kg.
Sources: Weight transfer — longitudinal load transfer · Milliken & Milliken, Race Car Vehicle Dynamics (SAE International, 1995)
Frequently asked questions
How do you calculate weight transfer under braking?
Multiply the vehicle weight by the deceleration in g and by the CG height, then divide by the wheelbase. Use the same unit for height and wheelbase; the answer comes out in the weight unit.
Do stiffer springs reduce weight transfer?
Not the total amount in a steady stop — that is set by weight, deceleration, CG height and wheelbase. Stiffer springs reduce body pitch and change how fast the load moves, which affects grip during transitions.
Why do front brakes do most of the work?
Because braking moves load forward, the front tyres can produce more friction. In a 0.8 g stop a typical car carries about 70% of its weight on the front axle, so brake systems are biased 60–75% to the front.
How can I reduce weight transfer?
Lower the centre of gravity or lengthen the wheelbase. Race cars are built low and long for this reason; on a road car, keeping heavy cargo low helps.
Related calculators
This calculator is for educational purposes. Double-check important results before acting on them.