CV vs. Double Cardan Joints

Guys, these are NOT CV joints. They are double Cardan joints. Big difference.


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Re: HD drive shaft on the cheap

That's technically not true. Double cardan joints are a TYPE of constant velocity joint, among others, i.e. Rzeppa which is commonly used in shafts connecting transmissions to the wheels on IFS setups.

 

My post IS technically true. A double cardan joint halves the velocity change of each single cardan joint in the assembly but there IS still a velocity change in each joint and the assembly as a whole. Not the case with a Rzeppa, double-offset, cross-groove, or tripod/tulip style which ARE constant velocity joints as there is no rotational velocity change as the angle increases. In a Double or single cardan joint the greater the angle the greater the velocity change. That's why we get vibrations from them and u-joint angles are so critical with them. Again, all a double Cardan joint does is halve the angle each single Cardan joint is operating at, it does NOT eliminate the velocity change inherent in a Cardan cross u-joint design.


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Re: HD drive shaft on the cheap

Sorry to kick this off!!

I'm aware they are not CV joints LOL.
At some point in the 70s all skid steer loaders somehow became "Bobcats".. (nomenclature). At some point years back all multi-jointed drive shaft connections somehow became CV joints.. (nomenclature). I have even noticed that some drive shaft shops refer to them as CV joints... and most of us know they are "actually" NOT CV joints.

If I'm not mistaken, they are referred to as double cardan joints in the Spicer parts catalog (but I would need to check)

So, I will re-phrase my post... "cut that thing off the end that has 2 u-joints in it"

Sorry for starting an age old technical clarifications session! ... just wanted to pass along a cheap way to upgrade your CJs rear drive shaft.

 

Texis, when I can get to my desktop I will separate the cv vs. double Cardan joint debate into a different thread. However, my comment stands, a double cardan joint is NOT a cv joint which you called it yourself in your original post. We do appreciate your information about another source for a propellor shaft to modify in these Jeeps.


Keep in mind these threads and posts are sometimes brought back up years later by folks using the search functions and I want to keep as accurate information on this site as possible. That's part of my job as a moderator.


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It's not a dead horse if the info is not readily available here and/or misinformation is stilling being perpetuated.
I didn't read it all but what I did read there was a lot of good info there so thanks for posting the link.


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Re: HD drive shaft on the cheap

Na, not a dead horse... just that that smiley!

BTW, that is my write up on how I built my own DC rear driveline...

 

Well, I'm ready to learn the difference between the two.:lurk:

 

I think I have an older textbook that I can send you for shipping costs if you want. It will also clear up "case" and "carrier", u-joint angles and a ton Of other things. Otherwise you will have to be patient until I have time to scan and post pics with explanations in between my two jobs, visit from out of town family, and putting the transmission back in my Jeep .


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http://www2.dana.com/pdf/J321-CV.pdf

Dana/Spicer calls them CV joints. But I guess the leading global supplier of driveline parts is wrong too.

 

ok so it says double Cardan constant velocity joint assy. on the cover but nowhere else in the book you reference.it is different than a cv. a cv is used in ifs or front wheel drive applications.a double cardan will not bend as much as a cv.


p.s. leave the tude at pirate...

 

Exactly what I thought.

Lets see, a college automotive instructor vs. an IT guy----------who do I think has the most credible background/knowledge in this discussion??

 

Sorry meant no disrespect.