What In Gods Name Were They Thinking?

[wayoflife]

The driveshafts are absolutely laughable. Only one real U-joint can be found. The rest are constant velocity joints. If you lift it, expect them to smoke. Fortunately there are no slip-yokes. We expect that several driveshaft companies will step up and offer a much-needed front and rear conversion (including yokes) to get some real U-jointed shafts in there. - JP Magazine
http://www.jk-forum.com/uploaded/jk-rear-driveshaft.bmp

Okay, maybe I'm missing something here, but what in the hell were the designers at DC thinking when they decided to throw in drive shats with CV joints? :naw:

I guess you may not need an SYE/CV to get you running 35's but new drive shafts may be in order :rolleyes:

[pmergler]

I guess you may not need an SYE/CV to get you running 35's but new drive shafts may be in order :rolleyes:

Okay I am new to the Jeep world, especially aftermarket off-roading, but what this is saying is the stock JK if you put on the aftermarket 2.5" lifts and 35" there would be a problem with the driveshafts? Just looking for a better understanding. Thanks -Pat

[wayoflife]

Okay I am new to the Jeep world, especially aftermarket off-roading, but what this is saying is the stock JK if you put on the aftermarket 2.5" lifts and 35" there would be a problem with the driveshafts? Just looking for a better understanding. Thanks -Pat
First off, I'm not 100% convinced that 2.5" of lift will get you riding on 35's without any rubbing but that's besides the point. The problem with the factory driveshaft is that DC decided to use weaker CV joints instead of the tried and tested U-Joints that have been on Jeeps... well, forever. And larger 35" tires will most likely be too much for CV's to handle. That's why so many in the aftermarket driveline industry are working hard at making new driveshafts that'll work with the JK... they know the market will be there.

[TJ Frank]

Those type of CV have been tested in the past by Ford if I remember correctly and they came back with the u-joint we know. There must be a good reason :yup: some make your own conclusions on this :rolleyes:

[Cesar]

Maybe it will improve the gas mileage?:confused:

[pmergler]

gotcha....thanks for explaining it. Are there any other downside to the CV other then not being able to spin > 35" tires? I would think it if had problem turning 35s that in very difficult climbing the drive shaft would face similar forces that could put pressure on the CVs. Is that not true?

[wayoflife]

gotcha....thanks for explaining it. Are there any other downside to the CV other then not being able to spin > 35" tires? I would think it if had problem turning 35s that in very difficult climbing the drive shaft would face similar forces that could put pressure on the CVs. Is that not true?
Yes, that might be true. Any which way you look at it, stock tires or not, this seems like a bad idea. Why DC decided to do this is beyond me :thinking:

[TJ Frank]

I guess that they need to leave some things for improvement :yup: so guys like us can change it ;)

[Cesar]

Thats right. Lets not forget. And I know I am not the first to say this.

Jeep are built, not bought!

[wayoflife]

Thats right. Lets not forget. And I know I am not the first to say this.

Jeep are built, not bought!
Amen to that and fortunately, there are plenty of aftermarket manufacturers of Jeep products to help us go broke... I mean, help us out :D

[Cesar]

Hmmmmm. Jeepers Anonymous

Hi my name is Cesar and I am a Jeeper.

hahaha

[DREDnot]

Before you guys get all wadded up about the CVs here, do you guys actually know anything about those particular joints?
So far all the info you guys have spouted is incorrect.
I dont mean to be harsh but unless they used inferior materials, these Rzeppa joints are the way to go.

On top of that, they are the same design the original WW2 jeeps used in the front axle.
They are also used in just about every front wheel drive and IFS four wheel drive including the HMMWV
They can handle more torque and angle than the cardan
The cardan is popular because it is cheaper to produce and easier to replace when it grenades due to lack of maintainance from John Q. Public

[wayoflife]

Do you really beleive that drivelines fail just because "lack of maintainance from John Q. Public"? Are you trying to suggest that a well maintained CV won't ever fail on the trail?

[DREDnot]

Thats not what I said at all.

In my years as a dealership mechanic, 9 out of 10 u-joint failures(cardan or rzeppa) were due to loss of lubrication.

John Q. just does not maintain his vehicle. Thats why the cardan cross is popular, because it is cheaper and easier to replace. Not because it is superior to the rzeppa.

How many people have lifted their jeeps and gotten the driveshaft vibes, then had to go with a new double cross CV and throw in a SYE while they are at it?

I see it as once again , Jeep has aready upgraded it for you.

Only time will tell if these factory Rzeppas will hold up. I am confident they will be fine with the stock tire sizes up to 34s.

Bigger than that always starts breaking stuff but I would rather have a bigger rzeppa than a bigger cardan:yup:

If you are prone to breaking your u-joints on the trail then yes, the cardan style is the way to go as it is easier to fix on the trail.

[Cesar]

Awesome! If we have WWIII and I get by a grenade I will be able to replace it quickly!