</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by aedavis:
<strong>Has anyone determined that draglink angle (relative to the ground) or draglink/tie rod parallelism (viewed from under the truck, looking up) has any effect on bump steer? The reason I ask is:
I recently installed crossover steering on my 85 4runner. The first time around I had the draglink bolting to the pitman arm with the tie rod end down, or closest to the springs. With this setup, I had perfect steering manners but poor clearance between the leafs and the tie rod end. I put spacers in to limit my uptravel to keep the leafs off the tie rod end. The draglink angle was shallow and it was perfectly parallel to the tie rod (viewed by laying underneath truck looking up).
To address my TRE/leaf spring clearance issue, I rebuilt the pitman arm to have the TRE going in from the top. After doing so, I have not been able to adjust out the bump steer. Two things are different - first, I have more draglink angle. Second, the draglink is not perfectly parallel to the tie rod. The driver's side could go back about 1/4" more.
Before I cut the steering box off and remount it a 3rd time, I wanted to see if anyone has been able to correlate bump steer with either of these geometry situations. A couple of threads here and on POR talked about draglink angle, but nowhere can I find reference to parallelism relative to the tie rod. </strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Drag link parallel to the tie rod (front to back) is not really a big issue. I ran my original AllPro crossover with about 2" of end to end difference for a few years and had no bump steer issues. I later moved the axle forward so the two rods are parallel front to back (not done to eliminate the angle but to gain wheel well clearance). Worked the same as before.
Then I dropped the front spring hangers for more spring-pitman arm clearance and then noticed some "bump steer". Not so bad with hitting bumps on the passenger side but when that side dropped into holes. Swapped steering stabilizers, changed spring bushings, etc. All helped a little but the steering was still bad. Then lengthened the spring shackle to be a bit longer than the spring hanger drop and its again solid steering.
Crossover Steering Evolution The angle on the draglink as it crosses the frame will lead to inherent bump steer. Hit a bump and compress the springs which flattens the angle on the drag link. That pushes the pasenger side tire out in front, you turn right. More angle = more bump steer. But I think having the steering caster angle set up right so that initial bump steer gets soaked up and damped out is the key. If it sets up a little bit of wobble when you hit the bump, that is not good.
