The Complete Handbook of Motorcycle Jackets

Chapter 1: Understanding Motorcycle Jackets

Motorcycle jackets are, at their simplest, a barrier between your skin and a road surface moving at speed. But to treat them as mere clothing misses nearly everything that matters about them. A motorcycle jacket is a piece of protective equipment with specific engineering requirements, and every design decision - the material, the zipper, the armor pockets, the cuff closure - exists either to prevent injury or to manage the physical demands of riding. This book treats them that way. Before you buy, sell, repair, or even wear another jacket, it is worth understanding what a jacket actually does, how it is tested, and where it succeeds and fails in the real world.

Consider the physics of a crash. The average rider who comes off a bike at 50 kilometers per hour will slide across asphalt wearing a jacket that is in contact with the ground for about three seconds. During that slide, the jacket's outer shell is being abraded by a surface that is far harder than it appears. Asphalt is essentially a composite of sharp-edged aggregates held in tar. It acts like coarse sandpaper, but with the grit fixed in place and moving relative to the jacket at the full speed of the fall. At 50 km/h, the outer material faces the equivalent of being ground against a stationary belt sander traveling at roughly 14 meters per second. Very few fabrics can survive that without tearing.

The single most important concept to grasp