Spiral Bevel Right Angle Gears are most commonly used to transmit power between shafts that are at a right angle or 90 degree orientation to each other - although almost any shaft angle is possible. There are serious benefits to the spiral bevel design. With these gears, the gear teeth gradually enter into mesh during rotation until maximum mesh is achieved. The teeth then leave mesh in the same manner. The payoff is that these gears run smoother, quieter, and have greater load capacity than straight tooth bevel gears.