Yeah, but then you have a really good excuse to upgrade your gears. Seriously, this is a good point. Seems like if you make an indestructible shaft, something's gotta give. Has there ever been anyone on here have that issue?

 

I think "indestructible" is an over used term. They are still a chromoly shaft, just like many other aftermarket shafts. They can still break at the shaft just the same as any other chromoly shaft. I listed the benefits before, the stronger joint that does not send a pulse when slipping tires, and rolled splines. This just means if they break, they will break away from the carrier and away from the knuckle, inside the tube where they can generate the least amount of damage.

And you get a killer warrantee.

 

Sorry man, could you explain the sending pulse bit.....does that mean this axle shaft will not transmit strongly down the line into the diff? Thanks for the response. I'm close to making a decision on new shafts, and would like to understand it a bit better.

 

No worries. I'll do my best to keep it simple.

By the properties of a u-joint, the angular acceleration of the joint loses consistancy as the angle of the two axis increase. In other words, the further you turn toward lock, the more the the speed of the output shaft (the shaft attached to your wheel) fluctuates during a 360* revolution compared to the input shaft (the shaft coming from inside the axle).

Here is a great plot to visualize how the speed "pulses" thru one revolution of the shaft depending on angle between inner and outer shafts (input and output).


That pulse causes varying power transfer, and in higher bind situations, can cause loading and unloading, resulting in traction loss and more force throughout the system.

Thats one of the beauties of RCV's they consistantly transfer power to the ground at the exact same speed and force coming from the differential.

 

Got it. As you increase the angle of the u joint, you'll get a wider fluctuation in output shaft speed within a given revolution, which causes greater loads on the entire system, not just the diff ( hope I said that right ). Even if my verbiage is not quite right, the graph fills in the blanks. So, basically, the RCV "tones down" the fluctuation as the angle increases, and you don't get these wild fluctuations, leading to early failure.

I don't think I've seen that graph before. Thanks for the help Mike.

 

The RCV doesn't "tone it down", it's straight up gone. RCV's are constant velocity joints. Speed in equals speed out.

Otherwise you got it down

Smooth transfer of power = smooth traction = less slip and spin = less breakage.

 

Thanks. I wanted to use my own words, otherwise I leave here thinking I got it, when I don't really got it. You know, not that.....that's EVER happened before!

 

So is the "pulse" you describe what causes jeeps to start to "bounce" when attempting to climb hard surface steep inclines? If so, going to RCV's to get rid of this dangerous problem makes them a smart investment.
I have 39,000 miles on my 07 Rubicon and have gone through 4 U Joints all on the passenger side. The only reason these failed was that I was unaware that a c-clip had fallen out, and as a result the cap eventually worked its way out as well. In order to stop the c-clips from falling out, I added a small amount of JB Weld. Should I need to remove a U-joint, I'll just take a small chisel and knock it off.

 

No. The pulsing of the tires is more pronounced the closer you are to full lock and is mostly noticable when you lose traction. I've been trying to find a good video example but can't seem to dig one up.

A rig bouncing while climbing is due to rear link geometry, specifically anti squat.

Tac welding the caps on is a great way to help keep them secure. They have a tendancy to back out as you said, and the more you lose caps and bust a joint, them common it is in that ear.

 

Great thread...learning a lot. Doesn't hurt to dab a little JB weld on the caps either until I change them out.