Weight transfer calculator
See how much load moves between the tires when the car brakes, accelerates and corners, and what each corner carries. Enter your car or start from the example FSAE car.
The car
Accelerations
Standing still
Braking at 1.50 g
88 kg moves to the front
Accelerating at 0.80 g
47 kg moves to the rear
Turning left at 1.50 g
52 kg moves across the front, 61 kg across the rear
Loads are shown as what each corner would weigh on scales. Left and right are the driver's.
How it's worked out
- Braking and accelerating: transfer = m × a × h ÷ wheelbase, split evenly between the two wheels on each axle.
- Cornering: each axle moves m_axle × a × h ÷ track from the inside wheel to the outside wheel.
- m is the mass, a the acceleration, h the CG height.
What it leaves out
It's steady state, with a rigid body. Aerodynamic downforce and drag, the split of lateral transfer by roll stiffness and roll center height, and transfer during transients are left out. To see how roll center height is set, try the roll center calculator. The free Contact Patch cheat sheet has the weight transfer formulas on one page.
Questions
Can I change how much weight transfers?
Not the total, without changing the car. It depends only on the mass, the CG height, the acceleration and the wheelbase or track. Springs, bars and roll centers change how the lateral transfer splits between the front and the rear axle, and how fast it happens, which is how they change the balance.
Why does weight transfer matter?
A tire's grip grows more slowly than the load on it. Moving load from one tire to another loses some total grip on that axle, so the axle that takes more of the lateral transfer runs out of grip first. More at the front tends toward understeer; more at the rear, toward oversteer.
How do I find the CG height?
Weigh the car level, then weigh it again with one axle raised a known height. The change in the axle loads gives the CG height. A CAD model with every part's mass is a good first estimate.
How does this calculator split the lateral transfer?
It gives each axle its own share of the mass, at the full CG height. Real cars split it by roll stiffness and by roll center height, so treat the front and rear numbers as a starting point. The total across both axles is right either way.
Is my data saved or sent anywhere?
No. The numbers stay in your browser.
More free tools: Roll center calculator · Spring rate calculator