Universal Joints

Ron0z

Active Member
I was kind of surprised to see a UJ on a front hub. Is that common?

I would have expected CV joints to have been used pretty much universally on all front wheels. I came across this video. (The interesting bit is at about the 13-minute mark.) I've become kind of addicted to watching Matt's Off-Road Recovery flicks. The characters are kind of funny at times, the videos are put together quite well and are entertaining, and some of the recoveries are amazing. Some are more interesting than others.

Anyway, you can see in the photo I snapped from the video that that's a UJ coming out right there.

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Ron0z

Active Member
Jeeps have been around for a while. Presumably, the design has stood the test of time. Universal joints are okay where there isn't much flex, like a tail shaft. Using them in the front where there's a lot of flex with steering seems like a cheap idea.
 

typhoeus

Well-Known Member
Jeeps have been around for a while. Presumably, the design has stood the test of time. Universal joints are okay where there isn't much flex, like a tail shaft. Using them in the front where there's a lot of flex with steering seems like a cheap idea.
remember, dana axles are not IFS. they are solid axles, so the unis only handle turning (steering) forces and do not have to deal with suspension flex etc. Cv joints are only really used on cars, not heavy equipment.
 

shanegtr

Well-Known Member
As mentioned it does seem to be a dana axle thing and is fairly common in Jeeps. Not so much an issue in a Jeep that's marketed as a 4wd vehicle, but a single uni like that will have the front wheels speeding up and slowing down in relation to the diff speed when the wheels are turned. Constant Velocity joints don't do this which is why they are so commonly used in front wheel drive and IFS vehicles as it will reduce vibrations in the driveline. The extra vibrations are probably not worthy of concern in a Jeeps design and usage requirements.
 

Ron0z

Active Member
UJs would certainly be cheaper to replace, and given they are fully enclosed within the axle housing they wouldn't suffer any stone damage.
 

typhoeus

Well-Known Member
As mentioned it does seem to be a dana axle thing and is fairly common in Jeeps. Not so much an issue in a Jeep that's marketed as a 4wd vehicle, but a single uni like that will have the front wheels speeding up and slowing down in relation to the diff speed when the wheels are turned. Constant Velocity joints don't do this which is why they are so commonly used in front wheel drive and IFS vehicles as it will reduce vibrations in the driveline. The extra vibrations are probably not worthy of concern in a Jeeps design and usage requirements.
The speeding up and slowing only happens as the angle of turn increases. When driving straight, the speed is constant. In agricultural, military an d heavy machinery applications, it doesn't matter much as just about everything is vibrating
 

shanegtr

Well-Known Member
The speeding up and slowing only happens as the angle of turn increases. When driving straight, the speed is constant. In agricultural, military an d heavy machinery applications, it doesn't matter much as just about everything is vibrating

Agree, which is why I mentioned it specifically.
in relation to the diff speed when the wheels are turned.
And everything that rotates vibrates.
 

Ron0z

Active Member
With the UJ on the Jeep, there will be the potential for vibration but without a load, any vibration will be of little consequence. When 4WD is active there will, of course, be a load, but there will likely be no significant vibration due to the speeds driven off-road. And driving off-road in 4WD, at speed, while negotiating a tight corner is probably never going to happen. If the road conditions are such then it might be best to be in 2WD.
 
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