How Speed Reducers Work in Vehicles

Speed reducers are nothing more than the normal gear systems that are found in typical cars today. The combination of gears in an automobile can be used to alter a car???s torque by either decreasing or increasing the rotation of the engine.

Speed Reducer and Torque

The reduction ratio is calculated using the formula 1/X, where X is a variable that represents the reduction ratio and is multiplied against the engine torque. This gives the result of the engine torque after the application of the speed reducer. This is the torque that is now applied to drive the engine. Speed reducers can either be spurs, worms or bevel and spiral bevel gears. Each engine type has its own speed reducer.

Types of Speed Reducers

Spurs are simply gear wheels that have radial teeth and that are positioned parallel to the axle. Worms on the other hand work by having another gear???s teeth that are positioned on an inclined plane interlock with the main rotating screw, thus acting like a worm as the name suggests. Bevel and spiral bevel gears operate at an angle that is anywhere between 90 and 180 degrees. They work like a worm gear by interlocking with another gear at a specific angle.

The Gears

Gear teeth help prevent slippage and to avoid this, axles are synchronized to exactly interlock with another. Usually, the number of teeth will control the gear ratio. Large gear ratios are achieved by connecting small and large gears together with one on top of the other. This interconnection allows ratio differences as high as 10-to-1. For example, a motor that is spinning at 100 revolutions per minute can be used to push another gear and rotate it at 1,000 revolutions per minute. Because of the friction that exists between the teeth, gears should always be lubricated to extend their lifespan and allow them to function properly. This will also ensure for smooth manual transmissions in most automobiles.


Speed reducers allow a car to operate at manageable speeds in addition to increasing the torque. The same mechanism for car speed reducers has also been used in other industries including factory machinery, hydraulics and in electrical equipment to run heavy-duty machinery. These speed reducers allow machinery and automobiles to be run in a cost-effective way while at the same time ensuring the safety of the operators, which in the case of vehicles, is the driver.

Speed reducers are a vital addition to an automobile or any machinery if they are to be operated efficiently.

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