Trac bar

[LILREDCJ6]

Hey when you do a shackle reversal do you still need the front trac bar? I don't think you do but, i don't want to leave something out and ruin something in the front end or crash the jeep.

Tony

[Lyle]

Hey Tony,

Let me first say ... I don't know. The suspension geometry stuff still confuses me, especially the differences between coil sprung TJ's and leaf sprung CJ's and YJ's. I can understand that the leaf springs do a better job of holding things in place laterally than coils. I did some searching and came up with the info below regarding bump steer in the YJ. So, I'm guessing it's a matter of how much lift you have, and if you're experiencing bump steer. Anyway, hope the following helps:


"On YJs, bump steer is caused by this simple fact:

The leaf springs want to move the axle straight up and down. Meanwhile, the drag link end that attaches to the tie rod swings in an arc; as it swings, it's lateral position changes.

The end result is that as the suspension rises and lowers, the drag link is moving side to side, which causes steering input. That's why it's called bump steer: when you hit a bump, the suspension compresses and creates steering input.

If your YJ still has the front track bar attached, it should theoretically minimize bump steer because the track bar swings in a parallel arc to the drag link. So, during the suspension cycling, the track bar moves the axle and tie rod laterally by about the same amount as the drag link so, relative to each other, the tie rod and drag link are stationary. End result? No steering input (bump steer).

Of course, adding a lift kit changes all this. The dropped pitman arm (IF the kit comes with one) doesn't match the geometry of the drag link; or the track bar extension bracket results in a geometry that doesn't match the drag link; or like many YJ owners, the track bar is removed altogether since it's frame mount bolt keeps loosening and banging around, anyways.

Ensuring that the drag link and track bar angles match is a good way to eliminate bump steer on lifted TJs but it doesn't always worked with lifted YJs because of the conflict between the leaf springs and the track bar. Remember, the leaf springs just want to go up and down while the track bar and drag link want to trace an arc. This invariable results in binding which means limiting the vehicle's suspension articulation. The steeper the track bar / drag link angle, the more direct the relationship between the vertical and lateral movement.

In my opinion, the BEST way (but also the most complex and expensive) to eliminate bump steer is to move the tie rod higher so that the drag link angle becomes almost horizontal. At this angle, any vertical motion will result in very small mounts of lateral travel and therefore almost unnoticeable bump steer."