Question, at this point and time if the axles are getting re worked couldn't the yoke ends and u joints get replaced with a CV joint? I know it sounds crazy to put that amount of work into it but nothing else on this set up has been easy. Or i guess cruise it for awhile and see how everything holds up.

 

After consulting with my local drive line shop they informed me that the u joints work well up to a 6 degree angle. They also informed me that that angle isn't necessarily the actually wheel camber angle but is influenced by the inboard u joint angle as well. He mentioned with the vehicle being on an air suspension that I can determine the best ride height based off what that angle is. He also agreed that the closer to that 6 degree you are the quicker it will chew those joints up. He didn't feel a CV joint conversion would be necessary.

 

To my knowledge, there isn't any CV joint that can hold the axial load like a U-joint. Remember that the half-shaft is the upper control arm in the setup.

 

Do you plan at driving at highway speeds? If so, you'll likely have vibration issues well before the 6 degrees. Sure, u-joints may "survive", but...

 

I've had someone mention once a CV joint that doesn't require a support. They said they were pretty pricey. At the time i didn't look into it because i assumed the U joint would be sufficient. Any clues on what they may have been referencing? Thank you all for the information and concerns. I'd rather sort this out and make a decision prior to "learning the hard way"

 

I think there are some CV joints that can take some amount of axial load, but I don't know of any that could handle the loads involved being a rotating upper control arm. I'm far from expert on the topic though, so definitely could be something out there I'm not aware of. Not sure at what angle you'd really start running into vibration issues. I know I've had issues with only couple degrees difference on a driveshaft. As half shaft with a wheel / tire on one end, there might be enough compliance in the tire to not be an issue. Or, the relatively short, very stiff half shaft could make it worse. Only one way to know for certain, try it and see what happens Can always shim them back out to -1deg, although you'll end up different geometry with shorter upper control arm. Other approach would be to lengthen the lower control arm a bit - cut, sleeve and weld. Doesn't solve the u-joint angle issue, but maybe easier and less expensive to experiment with.

Greg

 

Perhaps there was and yet available.

The wonderous 36 & 37 Cords were fwd. A Rzeppa joint used. Imperfect, but worked. restorers found a better unit to resolve any issues.

The Olds and Cadilac FWD cars had units that withstood decent HP and torque. 60's??

Teh off road guys max at more than 6 degrees. Joint life is shortened But the swap is much easier than the one contemplated.

 

Currently researching and waiting for the drive line shop to get back to me. He feels with this application a CV joint of any type isn't a requirement and feels the U joint setup will work fine (possible shorter joint lifespan). I'm not sure the juice is worth the squeeze on this one. I'm not extremely concerned about replacing a U joint ever couple years but would rather not sacrifice ride quality. Its a Sunday driver and doesn't see many miles a year.

 

Just meant to respond to CV can not handle the job.

 

Gotcha! I'm currently welcoming any and all advice/ information!

 

But the Cords and every other FWD cars are NOT using the half shafts / CV joints as part of the suspension. They only transmit torque, the spindle is located through other means. On the Jag IRS, the halfshaft is a rotating upper control arm. It serves dual purpose of transmitting torque and locating the top of the upright. It's not a question of power. A CV joint can easily handle the power. CV joints are used all the time in modern, high-power IRS half shafts. But these IRSs all have a separate upper control arm and half-shaft only transmits torque. No CV joint (that I'm aware of) can serve the dual role needed in the Jag IRS.

 

Offroad guys aren't driving at highway speeds on pavement (no slip). And if they do occasionally drive on surface without slip, any driveshaft vibration issue is probably drowned out by the tire noise, etc. A compromise that works on an offroad vehicle. I'm not sure it'll be a good tradeoff on highway driven cruiser. All that said, I don't know the angle where vibration might become an issue. I expect you'd never have a problem with 1 degree or less. 6 degrees, I expect you're almost certain to have a vibration issue. Where's the acceptable break between 1 and 6 degrees? No idea.