Maximum Driveshaft Angle?

What is the absolute max driveshaft angle one could safely run at at highway speeds?

I just put a 2.5 inch lift on and the angle is at around 25 degrees per the level on my phone. The rear axle is already shimmed and the tcase is already dropped an inch-2 inches.

Who do you guys recommend for custom driveshafts?

 

Tom Woods 4x4. Good products and excellent advice too.

They suggest a maximum of 15º on their "Geometry 101" page.


Tom Wood's Custom Drive Shafts - Tom Woods Custom Drive Shafts Custom Driveshafts Specialist

 

They have a lot of good tech info too. Take a look at their article "Geometry 101." Angle shims may not be a good idea, depending on the configuration. With a conventional drive shaft, you want to split the total angle between both u-joints.

 

The angle of the shaft is 25 degrees relative to the center of the earth. Measure the angle of the face of the output yoke, and the angle of the face of the pinion yoke. Those should be equal. (If they aren’t, make it happen.) Now subtract that from 25, and that is the angle your joints are operating at.

As long as your shaft is properly phased and balanced, and the joints are lubricated, you can get away with a fair amount of angle past the recommended angle with only the longevity of the joints to suffer. But once those joints begin to show wear, make sure to swap them out immediately, because they will deteriorate and fail in dramatic fashion much faster at severe angles.

The rear joints on my 3b are running at around 25 degrees with only one issue in 20+ years, and it was on the descent of Mt Washington where it decided to fail.

 

There is a ton of info out there on this. IMO the 25° angle is meaningless unless you also measure the tranny angle and diff angle. I am no expert but have read a lot on this subject. Here is one example of how to properly measure the angle … Measuring and Correcting Angle Problems - Drivelines NW

 

So if I did this correctly my u-joints are operating at 20 degrees? *Give or take a degree on one of the angles as I’m using an app on my phone and not an actual tool

 

to the untrained eye . that looks too severe
maybe it needs one of these

 

Tom woods made me a really nice double cardan driveshaft. I have similar angles as you. I would run that driveshaft until the joints decided to fail. See how long it takes, then decide if you need a custom one maybe depending on what to find acceptable.

 

From the Tom Woods tech page...

"Many people mistakenly believe that a double cardan or C.V. type drive shaft will allow for greater operating angles than a conventional 2 joint or single cardan drive shaft. This is not true. Some types of C.V.'s will actually incur a binding interference at less of an angle than a standard two joint drive line, again depending on the individual components used. Additionally the C.V. itself is longer than more conventional components and will create a greater operating angle on the driveline, especially on very short shafts."


On the other hand, a double cardan puts all the angle at one end of the driveshaft, allowing the other end to run at a zero angle, if that helps.

 

good point

 

I would go drive it and see if you feel any vibration. Once your springs break in, they will sag a bit and the angle wont be as bad.
Where I think you will have a problem is when you wheel it. Much downward travel of the rear axle and you will bind up. Jack up the jeep by the rear bumper and let your axle hang to see if the drive shaft is bound up.
I went through this just last spring.... ended up with the double cardan joint.