Spur gears certainly are a type of cylindrical gear, with planetary gearbox shafts that are parallel and coplanar, and teeth that are directly and oriented parallel to the shafts. They’re arguably the simplest and most common type of gear – simple to manufacture and ideal for a wide variety of applications.

The teeth of a spur gear have an involute profile and mesh one tooth at the same time. The involute form implies that spur gears only create radial forces (no axial forces), but the method of tooth meshing causes high stress on the gear teeth and high noise creation. Due to this, spur gears are typically used for lower velocity applications, although they can be utilized at nearly every speed.