Ride Height & Aero 

From Airflow to Asphalt

In GT3 racing, air is as much a weapon as horsepower, and ride height is the trigger. Ride height is the vertical distance between the car’s chassis (or floor) and the track surface. In GT3 racing, it’s a critical setup parameter because these cars are highly aero‑sensitive. The closer you can run the car to the ground without scraping or stalling the floor, the more the underbody works like a vacuum, sucking the chassis into the tarmac for relentless grip. But it’s a balancing act: too low and you risk bottoming out over kerbs; too high and you bleed downforce and invite drag. Nail the aero‑ride height combo, and you unlock a car that’s planted in the fast stuff yet agile in the slow, turning airflow and chassis stance into pure lap‑time advantage.

Front Ride Height

Front ride height is a primary driver of both mechanical and aerodynamic performance in a GT3 car. Because the front axle is the first point of contact with the airflow, its height relative to the track has a cascading effect on the car’s balance, grip, and stability

Why Lower is Faster

• Lower Centre of Gravity (CoG): Dropping the nose reduces weight transfer in braking and cornering, improving stability and responsiveness

• Aerodynamic Efficiency: Keeping the front floor close to the ground increases the speed of airflow under the car, strengthening the low‑pressure zone that generates underbody downforce. This improves front‑end bite and high‑speed grip

The Limits of Low

• Floor Stall Risk: If the front is too low, the airflow under the floor can choke or stall, causing a sudden loss of underbody downforce — often felt as unpredictable understeer at high speed

• Bottoming Out: Excessively low ride height increases the chance of the splitter or floor striking the track over kerbs, bumps, or heavy compressions. This can damage aero surfaces, unsettle the chassis, and momentarily spike drag

Finding the Sweet Spot

Engineers aim for the lowest possible front ride height that still maintains:

• Consistent airflow under the floor across the lap

• Clearance for kerbs and track undulations

• Predictable aero balance in both high‑ and low‑speed corners

Trade‑Offs in Setup

• Too much front height: You reduce underfloor downforce and high‑speed front grip, making turn‑in less sharp and increasing understeer in fast corners, though you gain bump compliance and kerb stability

• Too little front height: You boost aero load and turn‑in response, but risk bottoming out, floor stall, and a nervous front end over bumps or in heavy braking zones

Rear Ride Height & Aero Balance

Rear ride height is one of the most powerful, and sensitive, levers for tuning a GT3 car’s aerodynamic balance. Adjusting rear ride height changes the centre of pressure. Even small changes can have a noticeable effect on how the car behaves through different phases of a corner. Rear ride height is one of the most powerful, and sensitive, levers for tuning a GT3 car’s aerodynamic balance. Even small changes can have a noticeable effect on how the car behaves through different phases of a corner.

Centre of Pressure Shift

Adjusting rear ride height changes the car’s centre of pressure, the point along its length where the net aerodynamic load is concentrated.

• Raising the rear tilts the car forward (increasing rake), which shifts the centre of pressure toward the front axle

• This forward shift increases the proportion of downforce acting on the front tyres, sharpening turn‑in and generally increasing oversteer balance

Rake and Floor Sealing

Increasing rake changes the underfloor geometry relative to the track surface

• A higher rear ride height can reduce the sealing effect of the floor’s edges and skirts, allowing more high‑pressure air to leak underneath

• This leakage can reduce underbody efficiency at certain speeds, especially in low‑speed corners where the diffuser isn’t fully energised

Diffuser Performance

At the same time, more rake increases the diffuser’s expansion angle and volume

• This can increase the low‑pressure area at the diffuser exit, boosting peak downforce at higher speeds

• However, the effect is often more “peaky”, meaning the aero balance becomes highly speed‑dependent. The car may feel extremely planted in fast corners but nervous or unpredictable in slower ones, especially over bumps or curbs.

Trade‑Offs in Setup

• Too much rear height: You risk instability in braking zones and mid‑corner oversteer, plus a loss of rear grip in slow corners

• Too little rear height: You may gain stability but lose high‑speed front bite, making the car understeer in fast direction changes

Aerodynamics vs. Mechanical Grip

Aerodynamic Effects

Lower Ride Height: More Underfloor Downforce

• As the front of the car gets closer to the ground, the underfloor venturi effect strengthens, accelerating airflow under the chassis and creating a low‑pressure zone

• This increases front‑end grip at high speed, sharpening turn‑in and improving stability in fast corners

• Lower height also reduces frontal area exposure to airflow, trimming drag and slightly improving straight‑line speed

• The lower centre of gravity reduces body roll, keeping the aero platform more stable through direction changes

Too Low: Aero Stall & Bottoming

• If the front is too close to the ground, airflow under the floor can choke, causing a sudden loss of downforce (“floor stall”) — often felt as snap understeer in fast corners

• Reduced suspension travel means the chassis can’t absorb bumps or kerbs effectively, leading to “skating” where the tires momentarily lose contact patch pressure

• Bottoming out can damage the floor or splitter, further hurting aero efficiency

Too High: Reduced Aero Efficiency

• Raising the front increases the gap under the car, weakening the venturi effect and reducing underfloor downforce

• More turbulent airflow under the chassis increases drag, hurting acceleration and top speed

• The higher center of gravity increases weight transfer, which can destabilise the aero platform at high speed

Mechanical Grip

In low and medium‑speed corners, where aero load is minimal, mechanical grip is king.  Changes in ride height influence it in important ways:

Suspension Compliance & Tire Contact

• A slightly higher front ride height allows more suspension travel, letting the tyres follow bumps and curbs without unloading

• This can improve traction on rough or uneven surfaces, especially in street circuits or older, bumpy tracks

Weight Distribution & Load Transfer

• Lowering the front shifts static weight forward, increasing front tire load, which helps rotation in slow corners, may cause front overheating

• Raising the front shifts weight rearward, which can improve rear traction on corner exit but may induce understeer on turn‑in

Balance Across Corner Phases

• Too low: sharper turn‑in but harsher over bumps, risking mid‑corner instability if the front skips

• Too high: smoother over bumps but lazier response, especially in quick direction changes

Brake Ducts 

Brake ducts regulate the amount of cooling air directed to the brake discs, helping maintain them within their optimal temperature range

• Setting 0 = fully closed ducts: Minimal airflow, higher brake temperatures, and risk of rapid brake wear (temps can exceed 1000 °C)

• Increasing the brake duct value opens the ducts, allowing more air to pass through: faster cooling and lower peak brake temperatures

Why Brake Ducts Matter

Brake ducts serve multiple purposes:

• Brake Cooling: Prevents overheating and excessive wear

• Tire Management: Cooler brakes reduce heat transfer to the tires, helping maintain grip

• Aero Balance: More open ducts increase drag and can subtly shift aerodynamic balance

Monitoring Brake Temperatures

In ACC, brake temps are shown via a color-coded UI:

• Green = optimal performance

• Red = too hot

• Blue = too cold

Optimal Temperature Targets:

• Front Brakes: 600 °C – 650 °C (operating window: 300 °C – 700 °C)

• Rear Brakes: 450 °C (operating window: 300 °C – 600 °C)

Aero & Performance Trade‑Off

• More open ducts: Better cooling, more drag, slightly reduced top speed

• More closed ducts: Less cooling, less drag, higher top speed, but risk of overheating

Setup Tips

• High-speed circuits: Run the smallest brake duct opening possible without overheating to maximize top speed

• Technical/handling circuits: Open ducts more to maintain optimal brake temps during frequent braking zones