This profile has the very important property of maintaining a constant speed ratio between the two gears.

The speed ratio and mechanical advantage are defined so they yield the same number in an ideal linkage.

Thus, the speed ratio of a gear train also defines its mechanical advantage.

In large speed ratios or small central distances, the angle of contact between the belt and pulley may be less than 180 .

The Turboglide actually had two speed ratios in reverse, with one of the turbines rotating backwards.

Tilting the balls changes their contact diameters and varies the speed ratio.

The splitter was available in two versions, featuring slightly different low speed ratios.

This shows that for an ideal mechanism the input-output speed ratio equals the mechanical advantage of the system.

The speed ratio of a machine can be calculated from its physical dimensions.

A single action rotates both surfaces at a fixed speed ratio determined by the gear.