In motocross, there are two different types of goggle systems, having either roll-off or tear-off lens strips. Both systems are based on the same frames but have different features. As the name suggests, tear-off goggles are equipped with tear-off strips. There are posts on each side of the goggle lens to which the tear-off strips are fixed. Before each race, about six to seven strips of film are inserted onto these posts so that while riding, the rider can actually pull off the top tear-off strip when he can no longer see clearly. He simply pulls on the extended flap of strip that sticks out directly next to the lens. To avoid accidentally removing all tear-offs in the process, only the flap of the topmost layer sticks out, while the other strips are attached to the goggle´s elastic band. A new flap automatically pops out each time a tear-off is removed.
The roll-off goggles, however, work directly over the lens via a moving film system, very much like a roll of photographic film. A roll of film is mounted on each side in a small housing to the left and right of the viewing aperture. When the rider pulls on the lever of one of the rolls, the film strip is pulled over the lens enough to allow the motocrosser to see clearly again. The dirty strip is then automatically rolled onto the other roll.
Generally speaking, tear-off goggles are more popular with riders, because the entire field of vision is kept free, while the rider with roll-off goggles has only a single clean strip to look through and peripheral vision remains limited. With roll-offs, there is also the danger that moisture can cause the film to stick to the lens and it can no longer be wound any further. Roll-off goggles are not much use on a sandy track either, because the fine grains of sand soon get everywhere and can even interfere with the roll-offs´ mechanism.