Glossary
What is Aero Balance? Centre of Pressure, Percentages & Tuning
Aero balance is the percentage of total downforce acting on the front axle, equivalently the position of the aerodynamic centre of pressure along the wheelbase. Because downforce rises with the square of speed, aero balance dominates handling in fast corners while mechanical balance dominates in slow ones. Most cars target an aero balance slightly rearward of the static weight distribution, typically 40–47% front, so the car remains stable at high speed.
| Adjustment | Front downforce | Rear downforce | Balance moves |
|---|---|---|---|
| Add front wing angle | Up | Slightly down (wake effect) | Forward |
| Add rear wing angle | Slightly down | Up | Rearward |
| Add rake | Up | Up a little | Forward |
| Lower front ride height | Up (until stall) | Neutral | Forward |
| Add gurney flap to rear wing | Neutral | Up | Rearward |
Mechanical versus aero balance
At low speed the tyres' grip is set by weight distribution and roll stiffness. As speed rises, downforce adds load to each axle in proportion to the aero balance. If the aero balance is further forward than the weight distribution the car becomes pointier as speed increases; if it is further rearward the car becomes more stable but understeers in fast corners. Drivers generally prefer the latter because high-speed oversteer is dangerous.
Measuring aero balance
On track, pushrod load cells or damper potentiometers against known spring rates give front and rear downforce versus speed. Without sensors, a constant-speed straight-line run at different speeds and a careful ride height measurement from data gives an estimate. Wind tunnel and CFD give the baseline map the track work refines.
Frequently asked questions
Why not match aero balance to weight distribution?
A slightly rearward aero balance makes the car progressively more stable with speed, which is safer and more consistent. Matching them exactly leaves no margin and most drivers find the car nervous in fast corners.
How much does 1° of front wing change balance?
It depends entirely on the car. On a typical GT car one degree of front flap moves the balance roughly 0.5–1.0%; on a formula car it can be more.
Does aero balance change with ride height?
Strongly, on any car with a working floor. Front ride height in particular changes front downforce, which is why ride height and rake sensitivity maps matter.
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