Upgrading 2021 Rubicon Rock-Trac Full Time 4WD Axle

[Billet Wilson]

I just purchased a 2021 Rubicon with the new rock-trac full time 4WD system. The new setup uses CV shafts vs traditional universal joints so Im in the process of determining what my options are to upgrade the axle in preparation for installing a lift + 37" tires.

Generally, when I upgrade an axle I either install a 1 piece RCV shaft (CV) and FAD delete, run 4.88 gears, and upgrade the balljoints or I replace the axle entirely with a ProRock 44. Since the new system already uses CV shafts stock, does anyone know its strength in comparison to the ones from RCV? Basically, If I simply upgrade the stock axle can I leave the factory shafts and only have to do the balljoints and gear upgrade (going 5.13 this go around)?

It would be awesome if someone has had the opportunity to tare into the new CV setup to confirm but with it being so new I haven't been able to dig much info up.

Any info would be greatly appreciated!

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[Mouse]

U-joints are weaker as the angle is increased. CVs eliminate this factor. So, it should be a safe bet that these factory CVs are stronger than the u-joint axles.

 

[Renegade]

I can attest that the u-joint is weaker than the stock Rubi front shafts themselves, so maybe the CV shafts would be considered an upgrade? Send them to me and I will let you know!

 

[Billet Wilson]

I can attest that the u-joint is weaker than the stock Rubi front shafts themselves, so maybe the CV shafts would be considered an upgrade? Send them to me and I will let you know!

LOL, I would think they would be stronger but I don't want to find that out the hard way. I've called a few companies to dig up some info but I haven't gotten to far. Dynatrac stated they would still suggest upgrading to an RCV shaft but didn't get into any specifics to why.

 

[Blade1668]

Mouse has already hit it out of the park. CV is stronger than a U-joint the only downside I know of with CV is the boot to keep crud out and grease in. I may have forgotten the actual strength loss at a angle but I think it's 30-50% of the straight on at 0° a CV joint has full strength if not close to it even in a turn. About the only times I've seen them fail is when bound up in a turn or shock loaded in axles other wise just worn out or no lubrication from years of use.... Damn I still need to replace one in my LJ since I've already changed one out. When one of them went bad so had the rear driveshaft U-joints had too.
Another good reason for manual locking hubs..... Less wear and tear on them, and the hub was the fuze not a U-joint that then takes out the ball joints and axle shafts too.

 

[tommyp]

Interested in this info too. Have the AWD case in my rig and wondering how strong the stock cv's are

 

[WILDHOBO]

I have a ‘21 rubicon that I’m putting 37’s on next month. Per the recommendation of my shop, I’m replacing the stock shafts with RCV’s. They’re reportedly stronger than oem CV’s, and like the OP, I don’t want to find out the hard way.

 

[81Mojave]

I just posted last week or so about this!
I have a Mojave and I was considering RCVs (really like them in my JK with a teraflex housing) but I wanted to know if those stock CVs would fit my stock axle housing.
iIf you do ever end up pulling them, would you mind counting the splines and maybe a quick length measurement on both sides?
I like the idea of CVs if I’m going to spend more time in 4 high.

 

[WILDHOBO]

I just posted last week or so about this!
I have a Mojave and I was considering RCVs (really like them in my JK with a teraflex housing) but I wanted to know if those stock CVs would fit my stock axle housing.
iIf you do ever end up pulling them, would you mind counting the splines and maybe a quick length measurement on both sides?
I like the idea of CVs if I’m going to spend more time in 4 high.

Will do. They are coming off next month. Remind me if I forget.

 

[81Mojave]

Will do. They are coming off next month. Remind me if I forget.

Awesome thanks

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