Solid Axle Chevy Steering

[K5Blazer]

In my quest to make a desert truck out of my K5 I am stumped on what type of steering to run. The stock front to back draglink doesnt seem to work to well in my opinion by allowing too much bumpsteer. I want to run crossover, but I have been told it is not the hot setup for the desert. Can anybody help me?

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[michael]

You might try these guys...they race a Blazer.
mkparker.com/goose

[ntsqd]

If you have custom front springs made I can see the stock arrangment working pretty good. What you would need the springs to do is to be very stiff in the section forward of the axle. Effectively turning that portion of the spring into a trailing arm. The length from the front spring eye to the spring pin would need to be adjusted to be exactly the same length as the draglink's joint to joint distance, and they would both need to be operating in a parallelogram. Then to compensate for the stiff front 'half'' of the spring I would make the rear 'half' of the springs very long. Move the shackle back at least a foot. The only issue I can see with this would be in exceeding the angularity of the TRE's. LA 4wd Toyota's are notorious for troubles with this.

Where the bumpsteer in the stock linkage comes from is due to the draglink's fixed length vs. the front half of the spring varying in length depending on where in it's cycle it is.
With cross-over the geometry of the whole system will determine if you've made the bumpsteer better or worse. If the draglink is parallel to the axle housing, or even slightly leading at the knuckle end, then as the springs flatten and get longer the draglink will be in the sweetspot of it's arc and not effect the tire's direction as much.
If, on the other hand, the pitman arm end of the draglink is leading the knuckle end by a significant amount then as the springs' flatten and get longer the draglink will be pulled further away from the sweet spot/zone which could have a drastic effect on the tire direction.
Whether the suspension will cycle enough for the arc of the draglink, as viewed from the front, to affect tire direction is probably the Achilles Heel of the project. In it's favor the draglink of a cross-over is comparitively long. Working against it is that it is hard to get the angle (as viewed from the front) to a reasonably flat position.

There is an unsprung mass consideration in that cross-over will marginally increase it. If you're worried about that little change (relative to the current unsprung mass) I think you're worrying about the wrong thing(s). Not that unsprung mass shouldn't be considered and reduced where possible, but that this change is a pretty small percentage.

Who told you that cross-over doesn't work in the dez ? I'm curious as to what their reasoning or experience is/was.

TS

I used swerve around my halucinations, now I drive right thru them.

[BRBoudreaux]

Here's a couple of examples.......

[K5Blazer]

ntsqd, your reasoning makes perfect sense. But the one thing I dont get is how you would make the front half of the spring stiff with relatively no movement compared to the rear half of the spring. I would just like to know what to tell Deaver when I go to get my front springs done. The person that told me that crossover was not the hot setup was one of my fellow K5er's.

BRB, is that an idler arm setup on the second picture you posted?

[K5Blazer]

I pulled this off an old solid axle chevy thread, can someone clarify this please?

"Fabricate left frame mount track (panhard) rod from Dodge BR/3500 and convert steering linkage to transverse links drag link with Haltenberger type linkage. for front axle."

[drtdevil93]

what we usually do is flatten out the front of the spring. the front of the spring is already stiffer due to the length compared with the back. i usually dont flatten it all the way, but set it up so at ride height it will be in the "sweet spot".

erik

[ntsqd]

The way those Nationals were built was that on the front end of the spring each leaf's tip came within ~1/4"-1/2" of the next upper leaf. The truck I saw phis done on worked reasonably well when the driver could be convinced to keep his foot in it. The gal showing her bare upper half just down from S/F @ B-Stow sure did that.......

From the looks of it I'll guess that the second pic is an idler arm. The first draglink appears to run btwn the pitman and the idler, the second draglink btwn the ider and the steering arm. It's purpose is to get the frame end of the second draglink forward enough to create that parallelogram I mentioned earlier.

The post you quoted has to be Bob Sheaves. Give serious thought to his advice. I think what he's saying is that if you do a cross-over (& appearently he feels that is the correct thing to do), then you should also make a panhard rod. I think I see where he's going with this. By forcing the axle to move in a lateral arc with the panhard you can remove or reduce bumpsteer if you can get the arcs of the panhard and the draglink to coincide.

Not being familiar with Haltenberger Linkage I tried a google search and got 7 hits. This:
"HALTENBERGER
A steering system consisting of a drag link that connects the passenger side steering arm to the Pitman arm. It is unique to Ford vans and light trucks." from: http://www.niat-training.com/OnLine/...lossaryH-Q.htm
And this: " STEERING
Type Haltenberger linkage (4x2), cross-tie linkage (4x4)"
from: http://www.springfieldford.org/truck..._features.html

This leads me to believe that Haltenberger Linkage is the typical linkage found on TIB & TTB Ford trucks. On a live axle I think this would generate toe-out in the bump portion of the cycle so I'm not clear on why he suggests it in particular.





TS

I used swerve around my halucinations, now I drive right thru them.

[K5Blazer]

I'll have to look at my friends Bronco tommorrow to get an idea of the Haltenberger type linkage.

I remember reading something about the ORD K5 and how he was running a panhard rod and he broke the mount off the frame. This makes me think that im either going to be breaking the mount or im going to be really hard on parts because as the suspension compresses its going to want to make the springs travel in a different arc than they were designed to. But of course I may be wrong since im just digging into the surface on this stuff.

[Bob_Sheaves]

Hi guys...

Yep, that's the idea. Also, you need to make sure the lengths through the mounts (NOT necessarily the centerline of the link, but the straightline dimention between piviots) is equal and the angle relative to the ground in the front view and the angle fore and aft in the plan view are the same (this creates a parallelogram between the draglink and the track bar).

The Haltenberger linkage is also used on the BR 4x4's to allow for a longer track bar and draglink (longer radius for the induced curve of motion). It is not necessary unless there is a difference in the length between the panhard (track) bar and the drag link. A small benifit is that the steering response is slightly better on the Haltenberger, due to the non-90 degree placement of the compression springs located in the tie rod ends that occurs in a conventional system where the tierod runs knuckle to knuckle, and the draglink attaches somewhere to the tierod.

As far as breaking the mount off the frame-that is a risk if someone doesn't know what they are doing and creates a bad design. As you noted, the loads on the springs are increased (generally not to the failure point), but more importantly, a lateral vector is now added to the frame rail, twisting it normal to the centerline of the vehicle-not good. That is why a proper design will add a crossmember from the left to the right rail near the panhard bar frame mount-to transfer loading between the 2 frame rails.

Best as always....

Bob

<P ID="edit"><FONT SIZE=-1>Edited by Bob_Sheaves on 01/13/03 06:22 AM (server time).</FONT></P>