6 wheel steer?

[Streetgliderx]

I apparently can't operate the search function well, I search rear steer and get every thread in the universe with "rear" in it. It's a lot to sort thru.

So I'm gonna post and ask,.... Can both rear axles be swapped for fronts and 6 wheel steer be made possible?

What at changes have to be made to make a front axle work in rear? Has anyone done this?

The rears will be hydro, almost sure this will require a separate pump for rear only.

This is just a thought so don't flame me too hard. But if it's possible I would like to fab it up.

 

[wreckerman893]

You would not want the center axle to steer unless you wanted the ability to "crab".
On the Gamma Goat, the PLS and HETT the front and last axle steer which allows a tighter turn radius.
To add it to an existing vehicle would require a lot of fab work and a good knowledge of steering geometry.
There might also be legal and liability issues in doing this since you are modifying a factory engineered system.
If the vehicle is strictly for off road use you would prob be alright.

 

[quickfarms]

It would be interesting but the geometry would take a lot if engineering and some experimenting to get it correct.

A friend did it on a two axle off road truck using a joy stick and it was fun.

 

[rustystud]

Our old "MAN" buses from Germany had rear axle steering. The center (drive) axle was not. The rears would only move up to 20 degrees and opposite from the front. So if your turning right, the front would be going right and the rear would be going left making for a tighter turning radius for the bus. The bus was 60 ft long. As far as making a deuce rear steer, it would not work as the center axle is too close to the rear axle, the geometry would be all wrong.

 

[doghead]

Why?

 

[wheelspinner]

Most likely because the pivot point (middle axle) is closer to the rear than the front. Therefore it needs to turn in some number to be determined ratio to the front.

 

[zebedee]

..also, a lot would depend on you keeping duals or if it's 'singled out'. Singles would give you more room vs body work etc. Conflicts with the suspension would also have to be considered.

You would not have to have the rears steer 1:1 with the front axle - only a percentage would greatly reduce your turning circle dia. A mechanical linkage would be possible a la the fronts on an 8 legger or Chinese six (both have twin front axles) if you were going permanent, otherwise a manual hyd system would need a "home" detente for when not needed. You would also not need the middle and rear axle steer the same either (HET trailer - each trailer axle going away from the tractor steers more than the preceding). Geometry figured correctly would eliminate wheel scrub and the tendency to under/over steer the front axle.


After all said and done - it would be a great engineering project, however I would not want to be involved in an RTA and the investigators focus in on the modification and "determine" that was the cause....

Newer artics [semi's/tractor trailers] in Europe are now commonly seen with steering trailer axles, resulting in almost no cut-in on corners.

 

[doghead]

I meant why does he desire such a modification. What need for this does he have?

 

[zebedee]

What need for this does he have?

"Need, what need?" - "we ain't got no stinking need".

Just the "Everest" syndrome.... or is it a 'Complex'..... Just 'cause (its there)!

 

[HanksDeuce]

“We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."
John F. Kennedy September 12, 1962

"This is just a thought so don't flame me too hard. But if it's possible I would like to fab it up."
Streetgliderx June 25, 2014

"Why 6x6 steer deuce? Because 'merica!"
HanksDeuce June 26, 2014

 

[Jeepsinker]

When I mentioned this in another thread some months back it was kind of a joke...

 

[ke5eua]

I suggest not to add it unless your vehicle is as long as a HET or PLS.

Even in the HET rear steer is a PITA when bobtail. It gets squirrelly with slight movements of the steering wheel doing 45.

Unless your rock crawling your deuce, I wouldn't recommend it.

 

[11Echo]

One of the trucks on my wishlist.......

 

[Streetgliderx]

I meant why does he desire such a modification. What need for this does he have?

What need for such an array of machines in your signature? "M817, M818, M819, M35A2 w/w, M35A2, M109, M931, M561 w/w, M274, M1008A1, M146, M105, M116A2, M101A2, Pioneer tool trailer, MEP-002, MEP-017A, 1990 Dodge Tug, 5ton winch shear pins"


i didn't need the deuce. But I got it......


that said thanks for all the positive replies. This is a 98% off-road rig once this would be completed. It's just an idea. I love to fabricate, have a fully furnished fab shop, would be cool to make a quick maneuver deuce. It is on 395's btw.

"Why 6x6 steer deuce? Because 'merica!"
HanksDeuce June 26, 2014

YES!!!!



and wreckerman made made a point that the middle axle wouldn't need to steer, would it not slide those tires if the middles were stationary? I was thinking the middle would turn less than but if it's not gonna be too hard on the axle a middle that didn't would make the fab a lot simpler.

 

[doghead]

I actually use most of the vehicles in my sig line. All but one is stock and all are used within/for their designed capabilities.

Understanding your need(desire to modify) is needed to get you to your end goal.

You'll probably want to lock out the rear steer when on road, for safety and legal reasons.

 

[M-1028]

It's possible, I'm sure the suspension would have to be modified. If you flip the chucks in the front axle's it gets the driveline within 2" of center, so the drive shafts would hook right up. I've done this on my past 2 crawlers.

I'm a huge fan of rear steer, but that seems like a bunch of work for not enough gain.

 

[BobS]

As far as getting the steering geometry goes....it ain't rocket science. You can lay it all out on a flat cement floor with chalk lines as long as you are accurate in measuring. All you need to do l
is lay out the centerline of each axle, then lay out the centerline of the longitudinal axis of the truck, then lay out the front tie rod centerline across the vehicle, and finally lay out the centerline of the tie rod end on each side if the truck and the centerPOINT of the front u joint in the steering knuckle on each side of the front axle.

Now roll the truck out of the way so you can work on your full scale drafting table ( the cement floor).

Now take your chalk line and connect the left u joint point to the left tie rod end point. Extend the line all the way back to where the longitudinal centerline crosses over the number 2axle centerline. This is the "Ackerman point" which will be your new steering point the new design will pivot around when it turns.

Repeat drawing a line on the right side connecting the same 3 points.

Follow me so far? You are almost done....