Ultimate Travel, Long Travel Drive Shafts
The ultimate travel drive shaft is used in applications requiring extreme amounts of stroke on the drive shaft, such as a shackle reversal system.
With the exception of the spline stub, This drive shaft is made with off the shelf components. Using a length of 1.375" diameter spline, made to automotive specifications. (Other companies offer a similar shaft made with softer agricultural components) The huge amounts of stroke are obtained by constructing the drive shaft so that this long spline fits internal into the tube section of the drive shaft. Assuming that we are beginning with enough length in the entire drive shaft, we would be able to build a drive shaft that from the point of full compression to the point of full extension, where the drive shaft will fall apart, will have a stroke of up to 22.5".
Using a 10.5" spline will add $130 to the cost of most drive shafts. Using up to 22.5" of spline will add $170 to the cost of most drive shafts.
Before ordering this type of drive shaft, or any other for an application requiring a long stroke on the drive shaft. I suggest that you measure for the lengths required at ranges of suspension travel. While compressing the springs all the way against the bump stops, measure for length. Jack the vehicle up to allow the suspension to droop freely, and measure for length. In any case we will need to put in a little "Fudge Factor" to allow for things like frame flexing and spring wrap.
It may also be wise to measure for joint angles at the full range of motion, because the drive shaft will still incur a binding interference at the universal joints at around 30 degrees (or less depending on the specific joint size & shaft type). This binding may require that you place some kind of limit strap on the front differential to prevent it from dropping to the point where you have this binding interference and the resulting failure, or you may want to consider our Super Flex joint.
There are a few down sides to this type of shaft that you need to be aware of. Among them are cost, service procedures, longevity and safety. The drive shaft is substantially heavier than most other drive shafts and is not suitable for high speeds. At higher speeds, this extra mass will create excessive forces on the output of the transfer case and the pinion.
If you need a limit strap, you want to see if there is a way to place a single strap directly over the differential housing itself (as shown below). This should still allow for near full wheel articulation but prevent the binding of the u joints. We just want to make sure that you are not buying more shaft than you can use.