CV Vs. double cardan

first questions is: why do i keep reading jeep posts where people keep refering to the front(sometimes rear) driveshaft as CV when in fact it's a double cardan??? i thought that a CV was something like a ball and socket, and a double cardan was the 2 U-joints next to each other. am i wrong or are people just using the wrong terms?

second: i thought i read somewhere that at one point and time XJ's (maybe other jeeps too. i'm not sure) did in fact come with CV joints. is that true and can anybody tell me which ones??? now the only time i've seen CV joints is in the front of front wheel drive cars. so i would assume that the CV's on XJ's would have been in the same location. so where my front axleshafts have a u-joint, those would have CV joints. correct??? now i could see a benefit in running CV joints in terms of not binding/stressing on far left or right turns like u-joints do. does that make sense, and can that be done??? any pros or cons to doing something like that???

thanks,
alex

They call the double cardan a CV b/c it is very close to Constant Velocity. The front driveshaft comes with one stock and when people install SYE's they need one on the rear driveshaft.
Yes some xj's came with CV's up front, I have never seen one but I think they around 86. Most people changed them out b/c they were weak at least that is what I have read.

Katarn

i had an 86 xj with a CV front driveshaft. the CV was at the t-case end and a u-joint was at the axle end. the CV was not on the axle shafts. the CV i had was like a can with 4 ball bearings in side. I blew the joint twice before i finally got rid of it.

Scorpio

You are correct. A LOT of people write CV when they are referring to a double cardan, and it isn't correct. It wouldn't be so confusing, except as already noted the 84 thru 86 XJs with Selec-Trac did use true CV joints in the front drive shaft and in the front axles. That drive shaft is the one sometimes decribed as the "beer can on a popsickle stick" shaft.

Can't tell you how many times I've answered a question about a front CV joint, only to have the person call me an idiot because what they had is a double cardan, and I was supposed to know that despite their describing it incorrectly. Usually happens with newbies to Jeep, who don't quite get it that not all years and models came with exactly the same equipment.

Can't tell you how many times I've answered a question about a front CV joint

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and what is your opinion on CV strenght over u-joints in the axles shafts.

if there were a benefit, is there a company that makes upgraded strength CV axle shafts that would be able to hold up to a medium agressive wheeled XJ???

i know crasy1_69 said he blew his CV driveshaft a couple times, but if it were doable and reasonable i was just thinking of the axle shafts. i don't see a need in my driveshafts.

I have been wheeling my 85 wagoneer with the cv-axleshafts ever since I owned it. Replaced driver side when I first got it because the boot was ripped and there was no grease.

I have had no problems with mine, but I only run a 2.5 four cylinder. I will see how they hold up at Winterfest. I will be bringing along a spare set of 297 axleshafts just in case.

Kim.