Cycling Aerodynamics: Apparel, Helmets, and Gear for Drag Reduction

What do cyclists wear to reduce drag?

To minimize aerodynamic drag and enhance speed, cyclists strategically select form-fitting, smooth, and specialized apparel designed to streamline the body and manage airflow efficiently, including skinsuits, aero jerseys, aero helmets, and overshoes.

The Science of Aerodynamics in Cycling

Aerodynamic drag is the primary resistive force a cyclist must overcome, accounting for approximately 70-90% of total resistance at typical cycling speeds. This drag is primarily composed of two factors: form drag (pressure drag), caused by the air flowing around the cyclist's body and bike, and skin friction drag, caused by the air moving over the surface of the rider's skin and clothing. Reducing both types of drag is paramount for improving efficiency and speed, particularly as velocity increases, given that aerodynamic drag increases with the square of speed. Apparel choices play a significant role in minimizing these resistive forces by optimizing the rider's shape and surface characteristics.

Key Apparel Elements for Aerodynamic Efficiency

Specialized cycling apparel is engineered with specific features to reduce drag.

• Cycling Skinsuits/Speed Suits: These are the pinnacle of aerodynamic cycling clothing, especially for time trials, track cycling, and triathlons.

  • Integrated Design: A skinsuit is a one-piece garment that combines a jersey and bib shorts, eliminating any potential for bunching or separation that could create drag.
  • Extreme Form-Fit: Designed to be incredibly tight and wrinkle-free, molding precisely to the rider's body to create the smoothest possible profile.
  • Advanced Fabrics: Often use a combination of smooth, low-friction fabrics (like Lycra or spandex blends) on leading edges and textured fabrics (e.g., dimpled or ribbed) on trailing edges or arms/shoulders to manipulate airflow, promoting boundary layer attachment and reducing turbulent wake.
  • Minimized Seams: Seams are often bonded, flat-lock stitched, or strategically placed away from the front-facing surfaces to avoid disrupting airflow.
  • Internal Zippers: Zippers are frequently hidden or reversed to maintain a sleek external surface.

• Aero Jerseys: When a skinsuit isn't practical, an aero jersey is the next best option.

  • Tight Fit: Similar to a skinsuit, an aero jersey is designed to be extremely form-fitting, eliminating any flapping fabric.
  • Longer Sleeves: Sleeves often extend closer to the elbow, providing a larger surface area for aero fabric manipulation and reducing skin exposure.
  • Fabric Technology: Utilizes smooth and/or textured fabrics in key areas to manage airflow.

• Aero Bib Shorts: Paired with an aero jersey, these complete the lower body's aerodynamic profile.

  • Compression and Fit: Designed for a very snug fit around the legs and hips, minimizing wrinkles.
  • Fabric Choice: Often use similar low-friction or textured fabrics as aero jerseys to ensure smooth airflow over the thighs.

• Aero Helmets: Crucial for reducing head drag, which is a significant frontal area.

  • Teardrop/Long-Tail Helmets: Common in time trials, these helmets have a smooth, elongated shape that tapers to a point at the back, designed to guide airflow smoothly over the rider's back.
  • Short-Tail/Road Aero Helmets: A more versatile option for road racing, offering a balance between aerodynamics and ventilation, with a smoother, more compact shell than traditional road helmets.
  • Integrated Visors: Many aero helmets feature integrated visors instead of traditional sunglasses, creating a seamless, uninterrupted surface.

• Aero Overshoes/Shoe Covers: Worn over cycling shoes, these are a simple yet effective aero gain.

  • Smooth Surface: Made from stretchy, smooth fabrics (like Lycra or neoprene) that cover the irregular shape of cycling shoes, buckles, and laces, creating a cleaner, more aerodynamic profile.
  • Ankle Coverage: Often extend up the ankle to smooth airflow around the lower leg.

• Aero Socks: A relatively new but impactful addition.

  • Smooth Fabric Cuff: The upper cuff of the sock is made from a smooth or textured aerodynamic fabric that extends higher up the calf than traditional socks.
  • Tight Fit: Designed to fit snugly without wrinkles.

• Gloves: While seemingly minor, even gloves are considered.

  • Minimalist Design: Often feature smooth, thin fabrics with minimal padding or bulk to reduce frontal area and maintain a sleek hand profile.

Fabric Technology and Construction

The materials and how they are put together are critical to aerodynamic performance.

• Smooth vs. Textured Fabrics:

  • Smooth Fabrics: Used on the leading edges of the body (e.g., chest, front of arms) to minimize skin friction drag and allow air to flow smoothly.
  • Textured Fabrics (Dimples, Trip Lines, Ribs): Strategically placed on certain areas (e.g., shoulders, arms, sides) to intentionally trip the laminar boundary layer of air into a turbulent one earlier. Counter-intuitively, a turbulent boundary layer can stay attached to the body's surface longer, reducing the size of the turbulent wake behind the rider and thus significantly decreasing form drag.

• Compression and Fit: The relentless pursuit of a wrinkle-free fit is paramount. Any loose fabric creates eddies and increases drag. Compression also offers physiological benefits, such as improved blood flow and reduced muscle oscillation, though the primary benefit for aerodynamics is the smooth contouring.

• Seam Placement: Modern aero apparel uses flat-lock seams or moves seams away from leading edges and high-airflow areas to minimize disruption. Bonded or ultrasonic welded seams offer the smoothest possible finish.

• Material Composition: Blends of Lycra, spandex, nylon, and polyester provide the necessary stretch for a tight fit, durability, and moisture-wicking properties, which are important for comfort and performance during intense efforts.

Beyond Apparel: Integrated Aerodynamic Strategies

While apparel is crucial, it's part of a larger aerodynamic ecosystem.

• Optimized Body Position: The single most significant factor in reducing drag is the rider's position on the bike. A low, narrow, and flat back profile minimizes frontal area and streamlines the body. Apparel works in conjunction with this position.
• Bike Geometry and Components: Aero frames, deep-section wheels, integrated handlebars, and bottle cages are all designed to minimize drag and complement the rider's aero profile.

Practical Considerations for Cyclists

Choosing aero apparel involves balancing performance with other factors.

• Comfort and Ventilation: The tight fit and specific fabrics of aero apparel, especially skinsuits, can sometimes compromise comfort and ventilation, particularly in hot conditions. Riders must balance aero gains with the ability to perform optimally without overheating.
• Cost vs. Benefit: High-end aero apparel can be expensive. For recreational riders, the marginal gains may not justify the cost compared to the significant benefits of optimizing body position. For competitive athletes, these small gains can be critical.
• Maintenance: Aero fabrics are often delicate and require specific care to maintain their integrity and aerodynamic properties.

Conclusion

Cyclists employ a sophisticated arsenal of specialized apparel to combat aerodynamic drag. From the seamless integration of skinsuits and the targeted fabric technologies of aero jerseys and shorts, to the carefully sculpted forms of aero helmets and the smoothing effect of overshoes and socks, every element is designed to present the smallest, most efficient profile to the wind. By understanding the principles of aerodynamics and investing in appropriate gear, cyclists can significantly enhance their speed and efficiency, turning marginal gains into competitive advantages.