Hi all! I'm almost ready to buy the Skyjacker 4 inch lift for my 2008 Unlimited. When I look up this lift, websites show that it is recommended that a dropped pitman arm also be purchased and used. What is a dropped pitman arm? Just trying to find out what it is, what it does, and if it is really necessary. Thanks

 

It correct steering geometry and should eliminate bump steer.

 

It will only correct the steering geometry if a track bar drop bracket is used for the steer axle. I'm not famillar with this kit. If no drop bracket don't get the drop pitman arm, as it will cause bump steer. You will be better off with a adjustable track bar.

 

Skyjacker calls for the drop pitman arm on the 4'' suspention lift kit . It adds $85 to the price tag. Money well spent for peace of mind.

 

You need to understand how the steering geometry works.

Research the kit you are looking at. Call Skyjacker about the drop bracket for the front axle.

Drop bracket=Drop pitman arm

NO DROP BRACKET=NO DROP PITMAN ARM

check out the threads about bump steer

 

So just to confirm what you're saying, adjustable track bar means no need for dropped pitman arm? I'm not sure I'm understanding the correlation.

 

The Rough Country 4" lift comes with the pitman arm and drop bracket, if you don't drop these the draglink and pitman get pretty bound up when your pass side tire is at full droop.

Also you have to use the adjustable track bar or the dropped pitman arm/drop bracket because with 4" of lift without them the lift will push the axle to one side more than the other.

 

Yes, but are you sure you want to go 5"? I went with 4" and I'm 6'2" and it's a little tall, I think the 3" would have been perfect with the 35s.

 

The Pitman arm is the part that the steering mechanism uses to swing and move the other steering components.

A dropped pitman arm is just a pitman arm that hangs lower to REACH the steering stuff it has to make move, once the jeep is lifted.

A picture of the Skyjacker dropped pitman arm...a stock arm will be more or less flat (No drop):




A flat example of a regular pitman arm:




The problem is that when you lift, the track bars are attached to opposite sides of the jeep...so when the frame goes up, half the suspension is dragged one way, and half is dragged the other way...and the steering linkages are part of what gets dragged over.

So - if the linkages remain level, and you hit a bump, it doesn't pull the steering to one side...if the linkages are higher on one side, a bump makes the tire act on the steering, and pull the linkages as if you turn the steering wheel, etc...(Bump steer)

If the Pitman am is hanging lower, but the part its has to attach to has been shifted over...the shift part has to be bought over to the attachment point...typically uncentering the steering again....

So - the bracket is to allow the linkage to stay level, but still give a way to get back to the pitman arm....

In other words...its a clunky old fashioned way of trying to make the parts go back together, w/o taking advantage of better techniques that have been worked out over the past few decades since dropped pitman arms, etc.

And one more thing to break....etc.

So - a dropped pitman arm is an old way to get the pitman arm down to the linkages, so they can stay level, and help prevent bumpsteer....and so can a bracket that just goes up to the pitman arm...essentially doing the same thing.



Anyway - if you add a bracket to get back to the pitman arm...using a dropped pitman arm can make you miss, and visa versa...they do include track bar BRACKETS...which, I assume, are a cheap version of an adjustable track bar's effect, in that they would be expected to shift the axle back over after the lift dragged it in the first place, etc.

IE:

1) The Track Bar needs to travel in synch with the Drag Link...in the same arc......to help prevent bump steer, etc....the drag link is connected to the lower end of the Pitman arm, .....the Track Bar is connected to the axle and the frame.

2) When you do the lift, it offsets both of these from each other....Raising the Frame forces the axle to swing towards the frame mount of the track bar, and makes the track bar angle up towards the frame, as the frame is now further from the axle, but connected by the same length Track Bar. (Hence ability to LENGTHEN the track bar can correct this ....)

3) The kit uses a Track Bar Bracket to RAISE the Track Bar UP, to help compensate for the shift in the above angle, rather than make the track bar longer (Saves $, bracket is <$ than bar...)

4) When you do the lift, the drag link is - um, Dragged, towards the Pitman Arm, as raising the frame raises the Pitman Arm, but the drag link is the same length, etc....so the steering is pulled towards the Pitman Arm, steering you as if you turned the wheel that amount, etc.... (Hence off-centering the steering, leading to confusion of the JK's 'lil "Don't Flip" brain, etc...AND, making the Drag Link and Track Bar travel in different arcs.

5) Depending on your JK, you may find the above to be a problem...so, an optional Drop Pitman Arm is, um, an option. This simply brings the lower mount of the Pitman Arm down closer to where it needs to be to allow the Drag Link to not be up at an angle to reach the Pitman Arm. And....that helps to restore the relationship between the Drag Link, and the Track Bar, as they are both more level again, so they can travel in the same arc again, etc.



Hope that helps a bit.

 

No, the drop bracket gets your axle back to center. The dropped pitman arm puts your track bar and draglink back to being parallel. If the track bar and draglink aren't parallel you will have bumpsteer.

With my RC lift (drop pitman arm and drop bracket) I have zero bumpsteer.

In the picture below you can barely see the track bar behind the draglink.