Glossary
Corner Weights and Cross Weight Explained: How to Scale a Race Car
Corner weights are the static loads on each of the four tyres, measured on scales with the driver and race fuel load on board. The key derived figure is cross weight, the sum of the right-front and left-rear weights as a percentage of total weight. Circuit cars aim for 50% cross weight so the car behaves the same in left and right corners; oval cars deliberately run more.
| Discipline | Cross weight | Left side % | Notes |
|---|---|---|---|
| Circuit (symmetrical) | 50% | ~50% | Any offset makes the car turn differently each way |
| Speedway sedan (dirt) | 52–58% | 52–58% | Extra left and cross weight helps it turn left |
| Asphalt oval | 50–54% | 54–58% | Lower cross than dirt; left-side weight is key |
| Karting | 50% | ~50% | Set by seat position; no spring adjusters |
How to corner weight a car
Put the car on four calibrated scales on a levelled pad, with the driver seated, race fuel on board, tyre pressures set and anti-roll bars disconnected so they do not preload the suspension. Bounce each corner and roll the car to settle it. Read all four pads and calculate front %, left % and cross %.
To raise cross weight, raise the spring perch on the right-front or left-rear (or lower the left-front or right-rear). Each adjustment moves the diagonal; use small turns and re-settle the car between measurements. Ride height will change slightly, so finish by checking it again.
Why cross weight matters
A car with 52% cross weight carries more load on the RF/LR diagonal. In a right-hand corner the loaded diagonal fights roll and the car tends to understeer; in a left-hand corner it oversteers. Getting cross weight to 50% on a circuit car removes that asymmetry so the setup changes you make affect both directions equally.
Frequently asked questions
What is wedge?
Oval racing's term for cross weight above 50%. 'Adding wedge' means increasing the RF + LR percentage, which tightens the car on corner exit.
Why disconnect the anti-roll bars?
If a bar is preloaded it transfers weight diagonally and corrupts the reading. Disconnect one end, scale the car, then reconnect the bar with no preload at ride height.
Can I fix left/right weight imbalance with the spring perches?
No. Perches only move the diagonal (cross weight). Left/right and front/rear split can only be changed by moving mass: ballast, battery, driver seat or fuel cell.
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