Everyone that has ever ridden a dirt bike knows that you don't even play around on one without wearing your trusty brain bucket. Even a small spill can cause life altering injuries if you're not wearing the proper safety equipment. But what makes that motocross helmet different than the old football helmet you have laying around the garage from back in your glory days? Well, for starters dirt bike helmets are designed to work in conjunction with a pair of goggles to protect your eyes from flying rocks and debris. Eye protection is made of special highly flexible plastic and it needs to be. A rock can come flying off the rear tire of the bike in front of you at up to 80 miles per hour.
Motocross Helmets also have another feature to protect against flying debris and that is the visor just above the riders eyes. These visors are almost always made of a pretty light plastic because in the event of a crash where the visor hits the ground first they are designed to break away as to not cause damage to the neck. Off road helmets also typically have much more ventilation that a street helmet. Motocross is a very physically demanding sport and greater airflow increases rider comfort.
Motocross helmets are typically made of either polycarbonate resin or a combination of Kevlar and carbon fiber.
