I tore two fronts apart today and I noticed the shafts on the one axle had some extra machining done around the yolks, any one have any info on this. Also this is for a guy wanting four wheel steer, and to keep the right steering geometry should I flip the tie rod around to the back side of the housing to keep the wheel on the inside of a turn steering more than the outside wheel (being set up on a ford)?

I thought the tie rod was SUPPOSED to already be behind the axle housing to start with. Isn't that the way they are mounted in the Army trucks?

You guys missed it. the tie rod on a stock duece and a half is on the back, corect, but the pumkin is off set to the pass. side. To make this fit better I will flip the axle around so the pumkin is on the drivers side, but after doing this the tie rod will be on the front.
Rockwells had a bit of engineering put into them in the sence that when turning, the inside tire will turn sharper (this is good). this is done by having the piviot point of the steering arm and the tie rod end slightly offset toward the other wheel (not straight forward of the SAI (steering Axis Inclination line). So when I flip the axle and put the tie rod in front the out side tire will now steer more than the inside wheel.
My question was wondering if anyone has run into this before or thought of it. And is it a problem to switch the outer knuckels side to side (will they fit like that).
On the other issue, I don't have alot of experiance with metalurgy but I have seen some differant casting marks and the marks on thease two shafts remind me of the marks on a nodular crank or my Strange Nodular 9" third member, Maybe its just me but I think the metal just looks a little differant.
Is this a possibility?
John

THe ford is passinger drop right?
Ford has always been drivers side drop. as far as I know.

Tie rod behind axle = good

as for the yokes??? Looks like someone just hit em with a grinder, but who the hell knows???

call boyce Equip?

just looks like someone polished off all the marks to me.

Hey john, these axles are made by many different manufacturer's, i have seen hunderds of these axles, some are nice, some are rough.Yes you can turn the steering knuckles around, no problem same geometry. steve differential eng. inc.

Originally posted by Flipper
I thought the tie rod was SUPPOSED to already be behind the axle housing to start with. Isn't that the way they are mounted in the Army trucks?

y e s !

Looks like someone just hit em with a grinder,

They were definately done on a lathe, and they are a little thicker in those areas. Oh well it is probably the differance in having diferant companies make them.
Thanks everyone,
John

Both of the front shaft sets I have have some machining on them. Id guess its just for clearance in the knuckle...kinda a tight fit.

Id think both sets of tie rods would need to be toward the center of the vehicle for proper Ackermann (or as close as its gonna get)
This would keep the tighter turning tires. both F&R on the inside of the turn

Id think both sets of tie rods would need to be toward the center of the vehicle for proper Ackermann (or as close as its gonna get)

you would be correct, except for that you're not. You have to remember that the rear axle turns opposite the front for hard cornering. That means that you want to have the outer tire(on the rear axle) actually turned LESS than the inner tire. Because the arcs are now reverse of what they are for the front axle.

Originally posted by JOHNS351C

My question was wondering if anyone has run into this before or thought of it. And is it a problem to switch the outer knuckels side to side (will they fit like that).

John


I did not have any problems switching the knuckels around

Id think both sets of tie rods would need to be toward the center of the vehicle for proper Ackermann

Not to be harsh but elf read it again. this is what I was thinking was right. the tie rod behind on the front axle, and the tie rod in front on the rear axle. both toward the center of the vehicle.
John

well, do whatever makes sense to you. But I have been planning rear steer for over a year, and I've thought about this issue several times, discussed it with friends, etc. We all agree that the tie rod needs to go behind. Look at any comp rig with rear steer, they ALL have the tie rod behind the axle. But... I couuuld be wrong...

Ok I see how your thinking of this. The Comp rigs that (set-up properly) have the tie rod in the rear of the back axle are useing axles that when on the front would have the tie rod in front of the axle. these axles (Rockwells) are designed to have them behind the axle when its a front axle. so the opisite would be to have the tie rod in front of the rear axle. If I get a chance I will draw it out on CAD.
John

You're gonna run them on the dirt, with big mud tires, probably with Detroits in em and you're worried about Ackermann angle?

It don't fakwin matter:flipoff2:

Do it how ever is easiest for you to fabricate

I will second what 4x4extreme said, they will flip flop with no major headache, except for those damn cone washers.

JYS

To have correct ackerman steering geometry, the knuckles must point rearward on the vehicle. No matter what you've done to the housing, rotated, flipped, etc....the knuckles point back.

If you run the knuckles in front you've got backwards ackerman which isn't effective. By switching to correct, youll achieve an increased turning radius. This applys to front and rear steering.

CJ

BTW, This only applies to rockwells and most 4x4's specifically. On race cars you have many more options. Due to the inherent limitations in the design of a typical standard solid axle.

CJ

Originally posted by CJ Lagos
To have correct ackerman steering geometry, the knuckles must point rearward on the vehicle. No matter what you've done to the housing, rotated, flipped, etc....the knuckles point back.

If you run the knuckles in front you've got backwards ackerman which isn't effective. By switching to correct, youll achieve an increased turning radius. This applys to front and rear steering.
CJ
I am feeling rather confident that you wrong about the rear. on this aplication you are right about the front where as on most aplications you would be wrong, and on the rear you are just flat wrong. what determins which way is corect is the steering arm and tie rod end piviot point in relation (left, right) to the point where the SAI line intersects the same horizontal plane as the tie rod end.
More simpily put, if the tie rod is in front from the factory reinstall it in the front and do just the oposite in the rear.
John

John,

I hope your ready to intelectually battle this out! :P

1st off. Don't be misled by factory designs...just because something came a certain way does not mean it is correct. There are countless examples of design flaws built into production vehicle.

2nd. The principle of ackerman is the same for front and rear steering, just because the axle is in the rear doesn't change how this works.

Back to our subject at hand. The only real way to effectively prove this is to use diagrams. I'll do my best.

These angles are exagerated to prove a point. They'll show I am correct :P

The First is backwards ackerman. This places the knuckles pointing forwards on the front and rear axles. It produces backwards ackerman. The outside tire is turning more than the inside. Not very effective.

http://www.admotorsports.com/knucklefront.gif

This is starting to look good..

You know the rules. No hitting below the belt, back off when I say to, and lets keep it clean.

Now get it on.

Here is knuckles pointing to the back. CORRECT ACKERMAN GEOMETRY.

http://www.admotorsports.com/knucklerear.gif

I'll get the diagrams with the axles turned proportionally correct tonight. I have to goto work now.

CJ

you have to keep in mine that the ackerman angle will be wrong because it is set up for a much longer wheelbase than what any of us are going to use.

OK maybee the words were just confusing, because I agree with you on this as a front steer, One thing thougth did you lable the "passenger steering arm" and "drivers steering arm backwards"? The way you worded everything else makes it seem like so. Ok I will try and draw this now to show why I think your wrong about the rear though.
John

Ok I hate mega CAD, anyone use this? So I used paint, this is what I think it should look like with the tires straight and the tie rods behind the axle in front and in front of the axle in the rear.

now I know it's primitive but I dont care!! This is showing the two left tires turning sharper than the two right tires. this is giving an example for the rockwells only.

I dont know what I was thinking with the green lines!!

a picture is worth a thousand words! I see what you mean now, and I was thinking in terms of having steering arms that were designed for a front tie-rod. Basically, you want the ackerman angle for the rear axle to point at the center of the front axle. Cool pics!