Castelli Fast Feet 4 Socks

There are many so-called aero socks out there. But the Castelli Fast Feet 4 sock has the development and test results to prove that it lives up to its name. The few socks that have been tested were likely evaluated using a static test while at rest, because that’s easier. But since a foot is constantly in motion, we developed a device that simulates the movement of the lower leg. And we conducted tests with real cyclists to validate the results. This sock can save 2 watts at 50 km/h. The latest version features an updated cuff fit for greater comfort and aerodynamics.

• Castelli’s Fast Feet project – for maximum aerodynamics
• Foot area based on the Castelli Rosso Corsa socks for comfort inside the shoe
• Polyurethane grip strips at the top to prevent the sock from slipping
• Leg section made of specially developed, grooved Lycra® to optimise airflow

• Product Name: Castelli Fast Feet 4 Socks
  
• Manufacturer: Castelli
  
• Material: Main fabric: 85% polyester, 15% elastane
  
• Ankle: 82% polyester, 18% elastane
  
• Compression: no
  
• Activity: Cycling
  
• Gender: men
  
• Usage bikesport: Road Bike
  
• Textile fabric: Synthetics
  
• Season: All Season
  
• Socks length: medium
  
• Socks version: no padding
  
• Model year: 2026
  
• Collection: Spring/Summer
  
• Weight: 50g