Solid round and tube strength differences.

[PStov98TJ]

Yes, pretty much. You'd have to strip an axle to a blank slate to accomplish this. But again, this is obvious I guess and not the reason Blaine is serving us some knowledge.

Yep. Like I said, all depends upon what you need.

For fun I did some more math...at least I think I did it right. Percent increase isn't my strong point.
The 2.75"x0.375" tube is 5% more resistant to bending than a 2.5" OD solid bar, 39% more resistant to bending than sleeving the inside of a 2.5"x0.25" tube with 1/8" wall tube, and it's 78% more resistant to bending than the stock axle. Obviously this is all in theory and could be slightly more or less in real life.

 

[bobthetj03]

Yep. Like I said, all depends upon what you need.

For fun I did some more math...at least I think I did it right. Percent increase isn't my strong point.
The 2.75"x0.375" tube is 5% more resistant to bending than a 2.5" OD solid bar, 39% more resistant to bending than sleeving the inside of a 2.5"x0.25" tube with 1/8" wall tube, and it's 78% more resistant to bending than the stock axle. Obviously this is all in theory and could be slightly more or less in real life.

Looks like a significant increase in strength even if your calculations are off a bit, which I have no idea if they are, lol! Would a truss provide similar strength increases? I know this has been thrown around.

 

[PStov98TJ]

Looks like a significant increase in strength even if your calculations are off a bit, which I have no idea if they are, lol! Would a truss provide similar strength increases? I know this has been thrown around.

That's more engineering than I'm qualified to do haha but I'd imagine it really depends upon construction and design.

I don't have direct experience with trusses, but as long as it's designed properly it should increase the strength of the structure in the same plane as the truss. Specifically in limiting vertical deflection of the axle tubes under hard braking, acceleration, or if you came down really hard on them. But if you also use the truss as a control arm attachment point, that adds a whole other set of forces.

So long story short, I'll defer to @mrblaine or someone else who has experience with trusses for a definitive answer.

 

[mrblaine]

Yes, pretty much. You'd have to strip an axle to a blank slate to accomplish this. But again, this is obvious I guess and not the reason Blaine is serving us some knowledge.

The example is to help when you see someone make a recommendation to internally sleeve an axle. You now know the actual strength differences and why sleeving should only be done on the outside.

FYI, there is nothing that prevents you from cutting the tube in half and making a clamshell arrangement that cuts around some of the brackets and mounts.

 

[StG58]

Read through this whole thing twice. Good show and thanks for sharing @mrblaine! ...and everyone else as well.

 

[Chris]

So in other words, all these internal sleeves I'm seeing are basically nothing other than a waste of money?

 

[mrblaine]

So in other words, all these internal sleeves I'm seeing are basically nothing other than a waste of money?

It all depends on the question being asked. Do internal sleeves add strength to the axle tubes? Answer- yes they do.
Do internal sleeves add enough strength to justify the cost and time to install them? Answer- probably not.

I know of a fellow that leads guided runs through Death Valley several times a year and supplies the vehicles for them. He only uses Rubicons and his current batch are the late model versions. In discussions with him he relates that the sleeves do nothing to stop the tube from failing but they are exceptionally helpful to line everything back up for welding it back together to get it back to town. He also relates he has a near 100% failure rate with the front axles cracking the tubes with or without internal sleeves. Something I can vouch for as I had one here that was sleeved and broken.

 

[Chris]

I know of a fellow that leads guided runs through Death Valley several times a year and supplies the vehicles for them. He only uses Rubicons and his current batch are the late model versions. In discussions with him he relates that the sleeves do nothing to stop the tube from failing but they are exceptionally helpful to line everything back up for welding it back together to get it back to town. He also relates he has a near 100% failure rate with the front axles cracking the tubes with or without internal sleeves. Something I can vouch for as I had one here that was sleeved and broken.

You would know better than I would, but on the new JK Rubicon "Recon" model, Jeep is saying that they strengthened the axles. Perhaps this was a common point of failure that they decided to address?

In regards to the front axle on the 2017 Rubicon Recon model, Fiat Chrysler said this:

The front axle gets tougher housing tubes and “heavy-duty end forgings,” which theoretically means you’ll be able to crash through and on top of rocks with better resiliency against damage.

 

[mrblaine]

You would know better than I would, but on the new JK Rubicon "Recon" model, Jeep is saying that they strengthened the axles. Perhaps this was a common point of failure that they decided to address?

In regards to the front axle on the 2017 Rubicon Recon model, Fiat Chrysler said this:

The front axle gets tougher housing tubes and “heavy-duty end forgings,” which theoretically means you’ll be able to crash through and on top of rocks with better resiliency against damage.

Don't know yet but I'll run across one at some point and figure it out.

 

[PStov98TJ]

In discussions with him he relates that the sleeves do nothing to stop the tube from failing but they are exceptionally helpful to line everything back up for welding it back together to get it back to town. He also relates he has a near 100% failure rate with the front axles cracking the tubes with or without internal sleeves. Something I can vouch for as I had one here that was sleeved and broken.

So this guy is having a 100% failure rate of the outer sleeves? Is that an inherent risk of sleeving axles? Or is he just really beating the piss out of those Rubicon's?

 

[mrblaine]

So this guy is having a 100% failure rate of the outer sleeves? Is that an inherent risk of sleeving axles? Or is he just really beating the piss out of those Rubicon's?

No, he only does the internal sleeves. Mainly so he has a way to line them back up when they break. High speed travel on washboard roads is about the worst way you can abuse a rig. It vibrates the crap out of everything.

 

[bobthetj03]

Other than the additional welding, your clamshell external sleeve method doesn't sound like it would be a whole lot of additional work/cost vs. internal sleeving. You have everything apart anyway. Measure and cut to clear the brackets, weld it up and done.