Front Drive Shaft Update

[C-Mack]

Looks like well built driveshafts and curious if their out of phase u-joints (old LR/RRC approach) on the front actually worked? Also, how did they determine the amount of phase they used? I could see it reducing the resonance/vibration but probably not eliminating it completely. Hopefully the owner will post their impressions somewhere?

 

[TCMColorado]

View: https://youtu.be/K8sqKSf-kMw?si=APZ1mYPwKkHHxoQi

This prop shaft is materially no different than the one sold by Agile Off Road and will suffer from the same vibrations at certain shaft rpm and torque load. The Agile shaft is also out of phase. This improves but does not eliminate the vibrations given the joint angles of the Grenadier.

 

[Dokatd]

Ultimately you're still left with a drive shaft that has joints well out of operating spec. But I am not sure there is a real way around this issue.

 

[Lexx]

These U-joint type shafts remind me of the ones on big work trucks. And I do recall that those trucks tend to have some sort of grinding sound as they speed up or slow down. Perhaps that's a similar type of harmonic issues that the Agile Offroad and UK propshafts have?

 

[DenisM]

I lived with the UJ vibration issue in a RR P38 for years, especially if it was running ever so slightly higher ground clearance than spec with the air suspension. A single Cardan joint is not a true "CV"...never can be.. that's basic engineering physics. Indeed, increasing the drive angle on a single Cardan joint worsens the out of phase induced vibration.
At one stage I was tempted to import a Tom Wood double cardan shaft from the UK.... the $$$ curbed my enthusiasm.... dropping the ride height 18mm at cruising speed almost eliminated the vibration. Who knew??!
A double Cardan joint pretty much solves the vibration issues, eg. as employed on the Grenadier front axle! I was surprised that the chap in the video dismissed the double Cardan joint arrangement out of hand.
Surely the issue might just be to redesign the existing CV boot to allow more flexibility....