Front Drive Shaft Update

[Jiman01]

High RPMs occur because of high speeds; it’s all connected. The driveshaft rotates four times when the tire rotates once.

Maybe I’m missing something but the way I think about it, you can redline in 1st gear, like you can in 7th…but your speed (MPH/KPH) will be drastically different. If the vehicle only had one gear, I’d agree that the higher the RPM, the higher the velocity…..assuming there’s adequate traction.

 

[MK898]

The engine speed has nothing to do with the rotational speed of the shaft and the tires. The transmission separates these two from each other. The rotational speed of the tires and the shaft are always in a fixed relationship.

 

[Tinerfeño]

Here RPM doesn't refer to engine but to RPM of the drive shaft (prop shaft).

 

[Tazzieman]

Are our Euro friends (autobahn/autostrada) who routinely travel quickly (up to 160 km/hr) having propshaft dramas?

 

[MK898]

I never drive 160 km/h with the car. Otherwise, the boot would probably wear out even faster.


A week ago, I was at Manthey/Räder Motorsport and had the front differential raised as much as possible to improve the angle of the shaft. The car drives better than before with the new setup.


I’m curious to see whether this will have a positive effect on the lifespan of the boot.

 

[Tazzieman]

I never drive 160 km/h with the car. Otherwise, the boot would probably wear out even faster.


A week ago, I was at Manthey/Räder Motorsport and had the front differential raised as much as possible to improve the angle of the shaft. The car drives better than before with the new setup.


I’m curious to see whether this will have a positive effect on the lifespan of the boot.

Propshafdt speed thoughts.
I'm not sure of the failure rate according to country/highway speeds.
In Australia the speed limit is 110km/hr (except one state = 130 km/hr, only a small % of Grenadiers travel here) NA and Europe you travel faster, up to 160km/hr.
Lifts are one thing, speeds are another.

 

[MK898]

The differential was only adjusted in its angle, not “raised.” The car itself has been lifted by 3 cm.

 

[NQ94]

It isn't the proper solution to the issue at hand, but a driveshaft vibration damper could be made quite easily. Imagine a toroidal mass attached to the driveshaft yoke with a rubber sheet and a flat flange - on the transfer case side, it won't interfere with anything.
You inspired me to tinker with passive/active NVH suppression in a Gren.

Driveline dampers have been used over the years on front or mid mount engine buses and some trucks They're like a viscous damper on an engine.

 

[DenisM]

"Raising the differential in its angle'" to accommodate a 30mm lift and reduce the drive shaft angle implies to me that the diff was essentially rotated forwards at the top via caster settings.
By reducing the drive angle you induce  negative caster.
I can't reconcile how this improved the driving experience. I'd have thought the straight line stability would deteriorate.

 

[MK898]

The differential is adjusted to its maximum angle so that the angle of the driveshaft becomes flatter. I checked that myself. According to the report, it is now set to 0°. I’m absolutely satisfied and would recommend it to anyone. How it will affect the CV boot remains to be seen.

 

[Tazzieman]

Driveline dampers have been used over the years on front or mid mount engine buses and some trucks They're like a viscous damper on an engine.
View attachment 7921316

My reading says the best giubo dampers can flex up to 4.5 degrees without tearing.
What angles are we looking at with full articulation on a Grenadier?

 

[pmatusov]

My reading says the best giubo dampers can flex up to 4.5 degrees without tearing.
What angles are we looking at with full articulation on a Grenadier?

They are not supposed to flex!