The Complete Handbook of Bicycle Skinsuits

Chapter 1: Understanding Bicycle Skinsuits

When a time trialist crosses the line with a 0.3 second margin, and a skinsuit has been shown in controlled aero testing to save 5 to 12 watts at 40 kph when fitted correctly, that garment is not a piece of clothing; it is a component. It is a fixed and rigid piece of the rider-bicycle system, as governed by the physics of drag and the rules of the governing bodies as any aero handlebar or disc wheel. To understand what a bicycle skinsuit actually is, you must start by understanding the job it does, and that job is not simply "to reduce wind resistance." That is its goal, but its function is to manage the boundary layer of air that moves over the rider's body.

Cycling at racing speed is a battle against aerodynamic drag, which at 40 kph on a flat road constitutes roughly 80% to 90% of the total resistance a rider must overcome. Rolling resistance is a constant, largely independent of speed, but aerodynamic drag increases with the square of velocity. The rider's body, being a blunt, irregular object, is the primary source of that drag, responsible for an estimated 60% to 70% of the total. A skinsuit is the final optimization layer for that largest source of inefficiency. It does not make the engine more powerful; it reduces the load that the engine must pull. In practical terms, this effect is measured in watts. A 1% reduction in drag measured