distance travel than the input yoke quadrants. When one point of the output yoke covers the shorter distance in the
same amount of time, it must travel at a slower rate. Conversely, When traveling the longer distance (but only 90 degrees)
in the same amount of time, it must move faster.
Because the average speed of the output yoke through the four 90-degree quadrants (360 degrees) equals the constant
speed of the input yoke during the same revolution, it is possible for the two mating yokes to travel at different speeds.
The output yoke is falling behind and catching up constantly. The resulting acceleration and deceleration produces a fluctuating torque and torsional vibrations characteristic of all Cardan U-joints. The steeper the U-joint angle, the greater the fluctuations in speed will be. Conversely, the smaller the angle, the speed will change less.