In the world of performance tuning, downforce and aerodynamic balance are critical for achieving maximum control — especially at high speeds. While front splitters and rear wings often get the spotlight, side skirts are just as vital in completing the aerodynamic equation.
At ASM Tuning, our carbon fibre side skirts are designed using 3D scanning, CAD precision, and CFD validation to enhance performance and ensure OEM+ fitment. In this article, we break down what side skirts do, why carbon fibre matters, and how they tie together your aero package.
What Do Side Skirts Actually Do?
Side skirts are long panels mounted along the lower sides of a vehicle — right beneath the doors, from front wheel arch to rear. Though they may seem like cosmetic trim at first glance, they serve a powerful aerodynamic purpose.
Their primary job is to manage the interaction between the high‑pressure air around the sides of the car and the low‑pressure air underneath. Without side skirts, air can spill underneath, reducing the effectiveness of a splitter or diffuser.
Their main aerodynamic roles:
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Prevent high-pressure air from spilling underneath the car.
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Maintain low-pressure zones under the chassis.
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Guide airflow along the car’s side to the rear diffuser.
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Increase the efficiency of front splitters and rear wings.
Without side skirts, high-pressure air from the sides disturbs the low-pressure underbody flow — reducing downforce and increasing turbulence. The result? Less grip, more lift, and unpredictable cornering at speed.
How Side Skirts Improve Aero Balance
Aerodynamic balance is the distribution of downforce between the front and rear of a car. Without balance, a car can feel twitchy, understeer or oversteer aggressively, and lose stability during high-speed transitions.
Side skirts contribute by:
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Sealing the underbody airflow from side interference
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Working in synergy with front splitters and rear diffusers
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Stabilising air paths along the body to reduce lateral turbulence
CFD-tested data shows that performance side skirts can improve overall aerodynamic efficiency by up to 10%, especially when used with a full kit.
Why Carbon Fibre Is the Best Material
Side skirts endure not just air pressure, but also dirt, debris, and occasional impacts — especially on lowered or track-prepped cars. That’s why carbon fibre is ideal.
Side skirts need to be rigid enough to maintain their shape at speed yet light enough not to compromise performance. Carbon fibre excels here. It delivers the same or greater rigidity as steel or aluminium at a fraction of the weight. Removing weight low on the car reduces inertia and improves handling.
Key carbon fibre advantages:
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Extreme strength-to-weight ratio
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High rigidity – doesn’t flex under load
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Resistance to heat, corrosion, and debris
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Precision moulding for complex aero shapes
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Motorsport-grade aesthetics
ASM Tuning offers prepreg and dry carbon side skirts — both autoclave-cured for maximum structural integrity, ultra-light weight, and visual perfection.
Design Trends for 2025: What’s Changing
As we move into 2025, several trends are shaping the future of side skirt design:
🔹 Integrated air channeling – Some skirts now include sculpted fins that direct air into the rear diffuser.
🔹 OEM+ styling – Sleek, body-matching lines that complement factory shapes.
🔹 Dry carbon dominance – Prepreg and autoclave curing becoming the new standard.
🔹 3D scanning for fitment – Digital precision ensures plug-and-play compatibility.
🔹 Modular aero kits – Skirts that fit seamlessly into full front-to-rear packages.
ASM Tuning follows all of these trends — from scanning every car model in-house to ensuring fitment without cutting or drilling, and designing each side skirt for real aerodynamic value, not just looks.
Installation and Real-World Benefits
Fitment is equally important. ASM Tuning advises choosing side skirts with 3D‑scanned fitment for your specific model. Precision fitment ensures there are no gaps that allow air to spill underneath. Poorly fitted skirts can disrupt airflow and even damage paint if they rub or vibrate against the bodywork.
In addition to aerodynamic gains, side skirts offer:
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🛡️ Lower side panel protection from road debris
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⚙️ Stronger visual presence – lowers car’s stance visually
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🧰 Bolt-on installation – no body modification needed
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✅ Full kit synergy – pairs perfectly with splitters, diffusers, and spoilers
Every ASM Tuning side skirt comes with full fitment kits, optional clear-coat finishes (matte or gloss), and real carbon fibre manufacturing — no fibreglass blends.
Why Choose ASM Tuning
ASM Tuning is a global leader in carbon‑fibre aero components. Our components are 3D‑scanned, CAD‑modelled and available in dry or wet carbon. Every piece is finished with a UV‑resistant clear coat for longevity.
ASM validates performance through CFD and real‑world testing and offers after‑sales support and warranty. Whether you’re upgrading a BMW M car, Audi RS model or Nissan GT‑R, ASM’s components deliver both aesthetic and functional improvements.
Here’s what sets us apart:
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🔬 3D-scanned & CAD-designed for perfect OEM fitment
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🌬️ CFD-tested to validate aerodynamic performance
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🧪 Dry and prepreg carbon for strength, weight, and finish
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🔧 Global support and warranty for every component
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🧼 UV-stable clear coats protect against yellowing or cracking
FAQ: Carbon Fibre Side Skirts
Do side skirts really affect performance or are they cosmetic?
Yes — they dramatically improve underbody airflow and aerodynamic balance, especially when combined with other aero components.
Will carbon side skirts crack or fade over time?
Not ASM’s. Our prepreg and dry carbon skirts are clear-coated with UV protection and built to resist flex and fatigue.
Are side skirts road-legal and daily drivable?
Yes. All our side skirts are designed with safe clearance and are suitable for daily use — even in lowered cars.
Can I install them myself?
Yes — installation is straightforward with basic tools. We provide full fitment kits and instructions for every model.
Are they compatible with other brands’ kits?
While designed for ASM aero kits, our skirts often fit with high-quality third-party diffusers and splitters, depending on your setup.
Conclusion
Side skirts are a crucial piece of the aero puzzle. They seal airflow, increase downforce, reduce lift, and visually transform your car — especially when made from carbon fibre.
When you want precision, quality, and real performance gains, ASM Tuning’s carbon fibre side skirts deliver unmatched value. CFD-tested, CAD-engineered, and built with motorsport-grade materials — these skirts aren’t just for looks. They’re for winning.
