The double joint shafts of series 0.400.5 and 0.500.3 are intended for use in powered steering axles only.

As shown in the sketch below, when steering is activated, the axle system is rotated around pin center D. The double joint deflects at its two joint pivot points A and B. Since shaft II is fixed axially, shaft I must move in the direction S. This causes unequal joint deflection angles ß1 and ß2, and therefore, also a non-uniform (fluctuating) output motion. The fluctuation can be kept very small provided joint center C is offset toward the fixed side by the compensation value X. This way, at a certain deflection angle (= synchronous motion angle ßx) completely uniform motion is obtained, i.e., the two joint deflection angles ß1 and ß2 are equal.
ßx = 30° bis 35° would be an appropriate synchronous motion angle to select.

The center offset X required for smooth output
can be derived from distance a and synchronous motion angle ß:

Calculated center offset value X for individual joint sizes:
Series 0.400, synchronous motion angle ßx = 35°

Series 0.500, synchronous motion angle ßx = 32°

Sliding motion e at deflection angle ß, and also as a function of distance a and uniform motion angle ßx, can be calculated as follows:

Max. slide motion e for the individual joint sizes:
Series 0.400, synchronous motion angle ßx = 35°

Series 0.500, uniform synchronous motion angle ßx = 32°

Max. possible torque should be used for de-termining the required joint size. This could be the input torque, calculated from prime mover output, gear ratio and power distribution, or also the tire slippage torque, derived from allowable axle loading, static tire radius and coefficient of friction. The lower of the two values represents the maximum operating torque which should be used for determining the proper joint size. The double joint shaft selected this way will have adequate life expectancy, since the time percentage of maximum loading is usually low.

Double joint shafts, when not centered, must have a bearing support at both shaft halves right next to the joint with one shaft half fixed axially and the other floating axially. When torque is being transmitted, additional forces occur which must be taken into account when sizing the bearings.

Under torque, different force conditions exist at the joint spider pins and center piece with the double joint in an angled position than in a straight position. The reason for this is that the torque to be transmitted is not distributed evenly over the joint spider pins any longer. Also, as mentioned in Chapter 5, an additional moment occurs.
This additional moment must be combined with the torque to be transmitted.
This resulting moment leads to higher compression loads and to a larger bending stress within the joint spider pins.
The diagram below allows to take these factors into account. It shows the percentage the maximum allowable torque must be reduced in relation to the deflection angle.