Help with a front pinion angle question

[Modoc Guy]

IIRC, the rear pinion angle is good at 2 degrees angled downward.

And the front was opposite, 2 degrees angled upwards?
Or is it better to be closer to 0 degrees in front?

And in the front, would that apply regardless of low pinion or high?

Just wanna make sure I got this straight in my mind before I start fiddling around with my front pinion adjustments.

 

[Gollywomper]

The front pinion only need to be as high as needed to eliminate vibrations. It’s a bit trial and error. Do you have vibrations now?

 

[someguysjeep]

rear tends to like a degree low so it can torque up to the sweet spot.
the front is all left to the castor until it becomes an issue then you adjust the pinion angle just enough to stop it.

 

[freedom_in_4low]

Since the front isn't normally under load at speed there's no reason IMO to set it high. I think mine is actually 2-3deg below the driveshaft because that's where I liked the caster.

 

[Modoc Guy]

I have an HP30, so I don’t think I’ll have an issue with caster.

When I first put the HP30 in, it was angled up slightly and had vibration. Now it’s angled down slightly, and still has some vibrations.

And now that it’s been mentioned, since the front is usually not driven at freeway speed, the need to counter DS torque loading isn’t necessary.

That definitely changes how I’m thinking about it.

This Jeep is my first experience with adjusting dynamic DS pinion angles, and thankfully you guys here on the forum are helping me understand how I should look at adjusting them.

So, my next task is to do the adjustments in small increments above and below 0 degrees to find the sweet spot where vibration is at a minimum.

Just as a reference for caster, when my caster was at 6 degrees, I was about 2 degrees high at the pinion.
Then we put the pinion down about 2 1/2 degrees and my caster is around 8 degrees, maybe more.

And it just hit me, 0 degrees at the pinion ought to put my caster at about 7 degrees, which is the factory setting for a stock suspension IIRC.

Interesting

 

[Jerry Bransford]

rear tends to like a degree low so it can torque up to the sweet spot.

The front pinion angle moves downward under acceleration.

 

[Modoc Guy]

The front pinion angle moves downward under acceleration.

Thanks Jerry, that’s what I thought.