Join Date: Mar 2000
Location: Northern Catskill Mountains, NY
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Re: Drop Pitman Arm ??
Drop pitman will work fine. There are 3" and 4" types. Sounds like you will need the 4". However, there are problems with drop pitmans too, but that's another story.
The effect of bumpsteer is directly proportionate to the angle between the knuckle mount and the pitman. The more this angle increases, the more it will affect the amount of bumpsteer. It's a trig thing.
As for bumpsteer being caused by the springs hitting the drag link, that's not entirely correct. Bumpsteer will be noticed in both SpUA and SpOA configs, again it's directly proportionate to the drag link angle. In the SpUA, there is no chance that the springs will contact the steering linkage. In a SpOA, it's different. You have another problem to deal with. Since the springs are slightly above the tie rod and drag link, under compression, the springs can hit and rub against the drag (and sometimes tie rod). This is most noticable in hard left turns.
Hence, the drop drag or "Z"-type drag links. By making the drag into a Z shape, you dramitically reduce the problem of springs hitting stuff.
But the bumpsteer will not completely go away. In fact, I have not seen any noticable improvement with a Z link. The angle between the knuckle mount and pitman remains the same. And from what I remember from physics, the enegry (bumpsteer) will always move in a staight line, no matter what letter you configure the drag link to look like.
SO in steps the cross over or Knuckle-over steering set-ups. Hooray! Finally a way to get the drag and tie rod back to parallel (or close to it). For really tall lifts, a cross over and drop pitman usually does the trick.
There is also the Calmini "k" linkage. This is very similar to what is on Ford trucks. Eliminates bumpsteer using standard geometric principles. But this design is mainly for SpUA configs, as the spring rubbing issue may still remain. Ask Pugrocker about this set-up, as he runs one. Or call Calmini (Steve) and he can tell you more. I've seen it only a few times, but had it explained to me once.
Unless you plan on going higher (and you probably will someday), the 4" pitman will satisfy you.
Hope that helps (man, typing with one hand sucks)
<font color=blue>Yankee Tim</font color=blue>[img]/wwwthreads_images/icons/cool.gif[/img]