Spur gears are the most typical type of gears. They have straight teeth, and are installed on parallel shafts. Sometimes, many spur gears are used simultaneously to create large gear reductions.

Spur gears are used in many devices that you could see all over HowStuffWorks, like the electric powered screwdriver, Scroll Air Compressors dancing monster, oscillating sprinkler, windup noisy alarms, washing machine and clothes dryer. Nevertheless, you won’t discover many in your vehicle.

This is because the spur gear could be really loud. Whenever a gear tooth engages a tooth on the additional gear, one’s teeth collide, which impact makes a sound. It also increases the stress on the gear teeth.

To lessen the noise and tension in the gears, most of the gears in your vehicle are helical.