When selecting a speed reducer for a particular application, factors such as torque requirements, speed reduction ratio, efficiency, noise level, and space limitations must be considered. Other considerations may include environmental factors such as temperature, moisture, and corrosive substances.

The choice of reducer depends on factors such as efficiency needs, space limitations, and targeted RPM. Worm gear reducers are compact and suitable for optimal speed reduction in a small package. In contrast, worm reducers have higher shock tolerance and are preferred in low to moderate-horsepower applications. Bevel gearboxes are ideal for applications requiring right-angle reduction with a lower ratio and are more efficient than worm gears. Planetary gear speed reducers provide compactness and high power transmission efficiency, with a low-efficiency loss of only 3% in every stage.

They also provide better load distribution, which increases torque. Helical gear speed reducers are highly efficient and suitable for handling hung loads in higher horsepower applications where long-term efficiency is considered more important than initial costs. Helical gear reducers provide smoother and quieter operation than other gear types. This is because the teeth of the helical gears are angled rather than straight, which results in a gradual engagement of the gears, reducing noise and vibration. Helical gear reducers are available in both parallel and right-angle configurations.