panhard/lateral defl. limits???

[smokey]

Hey guys, still working on piecing my linked solid axle front end together.

I'll start with my question so anyone who doesn't want to read the background info doesn't get bored...
Pan-bars obviously shift the axle laterally as the suspension travels. What would you consider the max allowable shift from side to side? I'm trying to decide how much droop to allow, and what length shocks to run.

Now the background info for anyone curious:
Using a toyota mini truck front axle, I ran the longest pan-hard I could fit, which turned out to be 37 inches. The best I could figure out to mount it all while keeping my draglink/panhard equel length/parallel/same height/plane etc to minimize bump-steer, the draglink goes 4" past horizontal at full compression. Or in other words, 4" from full stuff, the pan-hard bar is level. At my estimated ride height, allowing for 8" uptravel, the axle end of my panhard is obviously 4" below the frame end.

Now a little geometry, and here's what I came up with:
total travel ............lateral shift at droop
12".......................0.875"
14".......................1.38"
16" .......................2.0"
18" .......................2.75"

FWIW, I already have some 14" shocks, but can't help but toy with the idea of more travel..I could always use the 14s in the back...;)
I'm worried about the front end feeling like it pulls sideways if I say, land a small jump at full extension, and the front end shifts 2" sideways as it compresses. How much lateral shift is tolerable? Or will the tires just slide in the dirt and it won't be a problem? Or finally, maybe it will be nearly un-noticed compared to dealing with getting bounced around when landing/hammering across bumps etc?

Or is there no point in trying to get more travel from a solid front axle? (ie unsprung weight and steering geometry issues are more of a setback than lack of travel)

Thanks in advance for any opinions, or preferably, experience :D

[Kritter]

side walls of your tires will take a lot of that side feel away...

[smokey]

Thanks for the input. As obvious as it seems, I hadn't thought of that.
When I compare my setup visually to something like the blitzkrieg blazer setup, which seems to be at a steeper angle than mine, I'm thinking that as long and flat as mine is, it won't be a huge issue in the dirt, but what do I know until I try it out.

Any thoughts on whether or not it's worth trying to squeeze more travel out of a solid front axle? I'm looking at about 15" now, unlimited, and could go up to about 18". But most of the gain would be in droop since I don't want to raise the ride height much more- until if/when I go to a wider track width.

[ElScorcho]

The only time you'll notice is on the street, otherwise your sliding around anyways. Another thing to think about is your bump stops. If you touch down on one corner first rather than both tires at the same time your axle will hit in a different spot. Just make sure your pads line up with one side at bump and the other at droop then switch sides and line em up again. Made this mistake personally already.

[JustinM]

I don't know exatcly how much lateral movement we had on our jeepspeed, but i wanna say it was well over an inch. The best thing we ever did to elimnate this is to get rid of that cast steering linkage everyone sells and make your self a set of chromoly rods with heim ends, but when you set it up, run your track bar all the way to the steering knuckle. this should let you stuff a longer pan-hard rod in there somewhere and keep lateral movement down a bit without getting the bumpsteer.

Not to say it is not important, but i wouldn't worry about the lateral travel as much as i would worry about the bump steer. your never going to get rid of it with a solid axle front end. If your going to do alot of desert damage with it you'll notice that every time you hit a bump it's going to have that split second of pull to one side as the axle moves to one side. if you throw bump steer in with that, it gets ugly. that's when we got rid of this cast steering linkages.

[smokey]

Thanks for the reply.

As far as I can tell, there's not much I can do to make the bumpsteer situation any better than it is now. I used that as one of my main building parameters, with everything else to fit around it, to an extent.

My drag-link and pan-hard are within 0.1" in length, run parallel and at the same mounting height at both the axle and frame, and my pan-hard mount is as far outboard as possible to still clear at full left lock. (by about 0.125" from the high steer arm)
At the other end, my steering box is mounted as far outboard as possible, to just clear the tire at full right lock. That sets the max length of my drag-link, and I built my pan-hard to match that.

From ride height through 8" of compression travel to full stuff, there is less than a quarter inch of lateral deflection. It's when it starts to droop that it moves farther, which is what I had some doubts about.

I'm still wondering if there's even a point in trying to get any more travel out of a solid axle rig that will never actually see the desert... :p