Front Pinon Angle

Any front-end vibrations? How is your steering return to center?

@bobthetj03 has tons of experience with driveshaft angles. Im sure he will provide some solid insite.

Just to clarify your not feeling any vibrations in the front end? Are you still running the stock control arms upfront?

The front pinion angle is a compromise, it has to be such that you get enough caster angle while not getting an excessive pinion angle. Pinion angle takes precedence over caster angle but both are important. If you're not getting front driveshaft vibrations and your steering returns to center ok after completing a turn, I wouldn't mess with the front pinion angle at all.

The way Blaine explained it to me, the front pinion is happiest when the pinion angle is higher than the driveshaft angle. Also, double check for any play in the slip yoke on the front drive shaft. There should be none.

The front shaft is a double cardan shaft so the angle from the t-case should not matter as long as it is within operating range. The pinion and pinion end of the shaft should optimally be on the same plane.

Following

Jerry Bransford said:

The front pinion angle is a compromise, it has to be such that you get enough caster angle while not getting an excessive pinion angle. Pinion angle takes precedence over caster angle but both are important. If you're not getting front driveshaft vibrations and your steering returns to center ok after completing a turn, I wouldn't mess with the front pinion angle at all.

Click to expand...

I have seen you reply with this a couple of times, and I am curious to mine as well. I don't have any vibrations and when I turn corners the steering wheel seems to come back to center sort of. I mean I think I may help it the last tiny bit. I think that it kind of wanders a little at high speeds. I have been able to adjust it out to perfect before, but now I have a new 4 inch lift and new tires and new currectlync Currie steering. it seems stiffer than before especially at center. kind of like driving straight down the road I need to slightly turn the wheel back and forth to keep it straight. I am not sure if it is normal for a tj with a 4 inch lift or I am just getting used to driving a new car with all new suspension. Also I have a anti-rock set in the middle that seems to sway a bit more than my old jks discos but again new 4 inch lift so might be normal. I am not sure what normal is to tell you the truth.

My question is my driveline has slightly more of an angle than my front pinion, and my front pinion is set almost exactly at 6 degrees. Should I keep driving it to let all of then new parts settle or do you think I should work on dialing it in a little more? (I have about 200 miles on it so far)

For instance if I turn a corner and let go of the wheel is it actually going to go back to exact center? I don't think it does. I think I give it a little leveling out. It is not annoying really, but if it isn't right and I can fix it, I will.

So like I was saying the pinion is slightly lower angle than the driveline in the front. I mean it is hard to see with the naked eye, but it is at 6 degrees and my steering linkage by linkage I mean the part that the tie rods bolt to on the hubs are level, will adjusting it up or down even be worth the time if so which way up or down? <--Meaning do I want to raise the arms on the hubs the tie rods bolt to or lower them? Or I guess I can ask a different way do I need to raise or lower my pinion more to make my steering wheel stop at center from the 6 degrees I am at? by the way it is at 6 if I raise the pinion it can go to 0 if that helps explain better where I am at?

The first thing I'd do is have the caster angle measured on an alignment rack and see what it is. I'd call around to a 4x4 shop to find one that has a rack, tell them you just need an accurate caster angle measurement, odds are they wouldn't charge much just to measure it. An alignment shop would likely charge far more to do that measurement. I don't trust being able to get an accurate enough caster angle measuring it with an angle finder.

dieselvrr said:

. . . Someone suggested shortening my front lower arms to adjust pinion but I didn't think that would help since it would move the axle towards the back of the car which didn't seem right.

Click to expand...

If you want to raise the front pinion angle you can lengthen the upper control arms.

dieselvrr said:

Doubt I'll be able to find a shop around my area willing to measure castor on a machine without charging.

Click to expand...

I didn't say a 4x4 shop would do it for free, I just said an alignment shop would likely charge more. It'd be worth a little $$$ to me to know what the exact caster (not castor) angle is to know for sure where the problem is.