Dana 60 Steering Help

Mac5005

Well-Known Member
Joined
Oct 19, 2005
Location
Rocky Mount
I stand corrected. I wonder how they can call them "correct akerman" if they don't build them to order based on your wheelbase? I guess close is better than not at all.

I think the only way to get the Ackerman even close to correct is to run the tie rod behind the axle, other wise the tre's will hit the rotor or wheel, when the tie rod is forward of the axle.

I'm no engineer, but I'm thinking that Ackerman is far more important at speed on the road, than slow speed on dirt. I'm also guessing that 4.5 psi in a 14" wide tire on a 9" wheel, with a front locker, is going to have enough "deflection" in the contact patch/sidewall to negate the need to invest time/money in correcting the Ackerman angle.
 

MarsFab

Will work for money
Joined
Oct 24, 2007
Location
Harrisburg, NC
At high speeds you hardly ever turn past a few degrees from center because most roads are made with relatively long flowing curves. Akerman is most important the the further from center you steer. ie. Trying to make a u turn.
Do you have a stock tie-rod laying around? Take your hi-steer rod off and put the stock one on it and see if it's better.
 

XJsavage

Warlock of Zante plantation
Joined
Aug 15, 2009
Location
South Carolina
If it helps at all, here's my setup. What's not shown in the pic well is a psc flat arm (drilled at 6.5"). Using the stock knuckle tie rod location makes a huge difference here and insures getting the 8" throw to match the ram. As I said earlier, my drag link ratio is 1:1 with a stock d&t'ed YJ box. Caster was built around 5 degrees caster and I left room for adjustment which I see no need to to date. Highway handling up to 80 mph is great even with flat square 42" bias ply iroks.
ai1266.photobucket.com_albums_jj521_XJsavage_Mobile_20Uploads_fab7e5d83fd263753b8a666cca048665.jpg
 

OnlyOneDR

Well-Known Member
Joined
Feb 10, 2006
Location
R
I think the only way to get the Ackerman even close to correct is to run the tie rod behind the axle, other wise the tre's will hit the rotor or wheel, when the tie rod is forward of the axle.

You could get proper Ackerman with the tie-rod in front. To achieve the correct angles the attachment point for the tie-rod moves towards the center of the vehicle from each side (ie the arms point inward a bit), thereby moving it away from wheels and tires.
 

MarsFab

Will work for money
Joined
Oct 24, 2007
Location
Harrisburg, NC
That's only if the steering is on the rear of the axle. On the front they go outwards. If you look in the picture he posted looking down on the hi-steer arms you'll see that the stock steering arm is out further the way it should be
 

Mac5005

Well-Known Member
Joined
Oct 19, 2005
Location
Rocky Mount
You could get proper Ackerman with the tie-rod in front. To achieve the correct angles the attachment point for the tie-rod moves towards the center of the vehicle from each side (ie the arms point inward a bit), thereby moving it away from wheels and tires.


That's backwards.
"Ideal" Ackerman would be a line drawn from the center of the rear axle through the kingpin centerline. The tie rod mounts would need to be somewhere on this imaginary line. If the tie rod mounts are in front of the axle, and inward from the king pin centerline, then the Ackerman is backwards. The farther you turn, the outside tire would turn at a greater angle than the inside tire. "Ideal" Ackerman is the inside tire turns a higher angle than the outside.

Most high steer arms that are advertised as "correct" Ackerman, really just move closer to zero Ackerman, where both tires turn equal amounts.

IIRC, the stock tie rod mount is the same distance from the king pin centerline but closer to the rotor. I'll check this weekend. If that is the case, the stock mounts would have closer to no Ackerman angle than the ballistic arms.
 

Falko

Well-Known Member
Joined
Mar 20, 2005
Location
Winston-Salem
@MarsFab achieving neutral Ackerman ( what im assuming you are referring to when you say correct Ackerman) is possible when the steering arms are angled in forward of the front axle. The Ackerman triangle is mirrored about the imaginary line connecting the king pin axis on both sides.

Why correct and neutral are not the dame thing? Many steering systems for dirt are set up slightly pro-Ackerman.
 

MarsFab

Will work for money
Joined
Oct 24, 2007
Location
Harrisburg, NC
Not necessarily true. Draw a circle around the kingpin that's the diameter of the steering arm path around it. Where the steering arm falls on that circle is what will determine what the linear movement of the tie-rod will do. If the arms are straight ahead then when they go left they will both travel in the same part of the arc of the circle. Here's a drawing I stole from YouTube that may make it easier to see. If you look at this drawing and imagine taking the steering arms to the front and pointed in towards each other you'll see that when turning left the outside tire will turn sharper than the inside. The opposite of what you want.
 

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paradisePWoffrd

Recovering Project Junkie
Joined
Nov 5, 2005
Location
Newton, NC
I hate to chime in so late but there are two extremely important things that have missed here. I built a samurai 5 years ago that had the exact same problem and I went through all this same stuff you are....
1st is the lack of attention to Akerman angle in aftermarket high-steer arms. Akerman angle is used in steering to eliminate the inside or outside tire scrubbing in a turn. When a vehicle turns the inside and outside tire travel in different radius. If this isn't right on a rig with huge soft tires and a rear or even front locker it will cut down on turning radius tremendously. Akerman angle is set buy changing the angle that the steering arm on the knuckle comes fore or aft from the kingpin. On almost all 4wd solid axle rigs we deal with the arms point to the front. If both arms point straight forward then both tires will travel in the same radius as the axle is steered. To get the ideal akerman angle you'd draw an imaginary line from the tie-rod hole in the arm back through the kingpin to the center of the rear axle on both sides. meaning the arms should point slightly outwards. The longer the wheelbase the less they will point outwards. That will make the inside tire turn slightly sharper than the outside as it should. Unfortunately in the 4wd world handling and proper steering are thrown to the side in favor of making the hi-steer arms and tie-rod ends clear large tire and wheel setups. Your arms appear to be completely straight forward. Strike 1.
2nd is that you desperately need a panhard bar. I've been in countless arguments over panhard bars on leaf sprung rigs and I'll stand firm on the fact that one IS needed. Your rig may drive fine down the road but leaf springs especially soft springs with some arch allow the front axle to move side to side under the vehicle. When you steer you are basically pushing the axle side to side via the steering box. Without a panahrd bar to locate the axle centered you will have much less responsive steering as well as a dead spot in the center of steering travel because the steering has to push the slack out of the springs/bushings left to right. That slack is why your steering radius sucks as well as the fact that your front inside tire is trying to drive straighter forward than the outside tire. These two things combined will do exactly what you are experiencing. Strike 2. I'll bet you a 20 dollar bill that if you put a panhard bar on your jeep you'll have a much better radius. Unfortunately there isn't much you can do about the akerman angle though. Unless you wanna machine your own hi-steer arms. I'm not aware of any companies that make hi-steer arms with proper akerman angle built in for a determined wheelbase.

Thanks for bringing this up. Ackerman completely slipped my mind. I believe it can help for sure, but not the only cause.

I stand corrected. I wonder how they can call them "correct akerman" if they don't build them to order based on your wheelbase? I guess close is better than not at all.

I would guess by "correct" they mean it is the same as a stock arm.

That's backwards.
"Ideal" Ackerman would be a line drawn from the center of the rear axle through the kingpin centerline. The tie rod mounts would need to be somewhere on this imaginary line. If the tie rod mounts are in front of the axle, and inward from the king pin centerline, then the Ackerman is backwards. The farther you turn, the outside tire would turn at a greater angle than the inside tire. "Ideal" Ackerman is the inside tire turns a higher angle than the outside.

Most high steer arms that are advertised as "correct" Ackerman, really just move closer to zero Ackerman, where both tires turn equal amounts.
Not necessarily true. Draw a circle around the kingpin that's the diameter of the steering arm path around it. Where the steering arm falls on that circle is what will determine what the linear movement of the tie-rod will do. If the arms are straight ahead then when they go left they will both travel in the same part of the arc of the circle. Here's a drawing I stole from YouTube that may make it easier to see. If you look at this drawing and imagine taking the steering arms to the front and pointed in towards each other you'll see that when turning left the outside tire will turn sharper than the inside. The opposite of what you want.

Correct. That picture can help a ton also. If you want the arms in front of the axle they need to point out, or in on the rear.

Another thing that is not mentioned here yet is Scrub radius. It doesnt play as big of a part here as the other factors, but it can effect steering. Turning radius in the dirt isnt effected as much as on surfaces with high traction, or when the tires get bound in rocks. Correct scrub can lower the steering effort and forces on the system however.

This article is about rockwells, but discusses ackerman and he shows the numbers from just changing the ackerman on his axle: http://www.pirate4x4.com/forum/gene...77-running-rockwell-knuckles-upside-down.html.
 

MarsFab

Will work for money
Joined
Oct 24, 2007
Location
Harrisburg, NC
"Correct" would mean that the imaginary line through the steering arms to the rear would intersect at the center of the rear axle as they should for zero tire scrub. This may or may not be right on a stock d60 knuckle. A d60 from a 140" wb crew cab long bed Chevy is not gonna be right for a 100" wheelbase wrangler.
 

MarsFab

Will work for money
Joined
Oct 24, 2007
Location
Harrisburg, NC
Scrub radius can definitely play a huge part in steering radius. A high scrub radius combined with improper Akerman is not good.
 

Mac5005

Well-Known Member
Joined
Oct 19, 2005
Location
Rocky Mount
about the panhard... When I mounted the front 60, I only moved one end of the springs outboard to match the offset of the spring perches. This means there is 3/4" or so of Taper in the springs. I'll have to dig up a video from years back and I was watching the front axle stay stationary when the tires were being turned on rock. I understand and agree that it would only help the situation. But for now, my main focus is get the steering setup capable of more angular degrees. I measured the angles on a concrete floor, so they will only be worse due to deflection of the axle from side to side in a real setting.
The main issue of not enough angle change due to different length levers in the steering system is my first priority.

I have a huge scrub radius. considering the width of the kingpins is roughly 52.5/56" for the top/bottom, yet the outside of the tire width is 89". Not planning to change wheels/tires or housings anytime soon, so this is unavoidable for now. The 215 lbs at each far corner away from the COG are very friendly in off-camber situations.

after giving it a quick look this afternoon in the rain, the ballistic arms move the tie rod mounts farther in than the factory, but are similar in distance from the king pins. this pushes the ackerman closer to none than the factory. Tie rod length is 53", and is 6.5" from king pin centerline. The drag link is 37.75" long, but mounts 8.75" from king pin.

The astro van pittman arm is only 6.5" long, while the waggy arm is 6.75" long.

If I mount the drag link to the tie rod, this will make the most difference in delivering the same angle change from box, to knuckle. The astro arm would transmit 71 degrees at the box into 68 degrees at the knuckle. The waggy arm would transmit 71 degrees at the box to 73 degrees at the knuckle, if the drag link is moved to tie rod.
 

MarsFab

Will work for money
Joined
Oct 24, 2007
Location
Harrisburg, NC
Well keep us posted on the swap. I'm interested to see how it turns out. I hope it works out for you. As we all know the struggle to make big tires and flexy suspension act right on and off road is real.
 

Mac5005

Well-Known Member
Joined
Oct 19, 2005
Location
Rocky Mount
Well keep us posted on the swap. I'm interested to see how it turns out. I hope it works out for you. As we all know the struggle to make big tires and flexy suspension act right on and off road is real.

After some time in solidworks, if Tie rod is 6.5" from king pins, then the tie rod needs to be 55.75 long, to have "correct" ackerman

Thanks again for all help everyone, really glad to get all the different opinions on this, definitely brought up a lot that I hadn't considered yet.
 

paradisePWoffrd

Recovering Project Junkie
Joined
Nov 5, 2005
Location
Newton, NC
If you measure the angular travel of the steering arm vs the angle of the tire you can see how scrub is effecting your turning
 

drkelly

Dipstick who put two vehicles on jack stands
Joined
Mar 21, 2005
Location
Oak Ridge/Stokesdale, NC
Here is a picture of the way I attached the drag link to the tie rod on my cab truck. I drilled a 3/4" hole through the tie rod tube and welded a 3/4" grade 8 bolt in.
image.jpg
 

fordtrucknut

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Joined
May 16, 2012
Location
bedford va
Just to add to this..if anyone is looking for different pitman arms ..A 78 f150 4wd is roughly 7 1/2 -7 3/4 center of hole to center of hole. ..A 78 f150 2wd is roughly 5 3/4 if anyone needs something that short
 

fordtrucknut

Well-Known Member
Joined
May 16, 2012
Location
bedford va
Drkelly..you didn't have any issues with running that set up?
Seems like it would weaken the tube in the area where you drilled the hole...
This is exactly what it looks like I need to do ...I've got jeep so low that there isn't enough clearance for the tie rod when it's on top of the high steer arm...soooo
 

fordtrucknut

Well-Known Member
Joined
May 16, 2012
Location
bedford va
Here is a picture of the way I attached the drag link to the tie rod on my cab truck. I drilled a 3/4" hole through the tie rod tube and welded a 3/4" grade 8 bolt in.
View attachment 178164
See above message sir

Now on to my next question. .is there any reason I can't put my tie rod on the bottom side of the high steer arm instead of the top and then run my drag link off of my right side knuckle instead of off of the high steer arm??
 

paradisePWoffrd

Recovering Project Junkie
Joined
Nov 5, 2005
Location
Newton, NC
See above message sir

Now on to my next question. .is there any reason I can't put my tie rod on the bottom side of the high steer arm instead of the top and then run my drag link off of my right side knuckle instead of off of the high steer arm??

Depending on your suspension, there shouldn't be an issue with that. It's best to flatten the angle of your draglink if possible to minimize bump steer

But it's likely the 2 links will hit each other at some point. Unless one is on the back and one on the front of the axle
 

fordtrucknut

Well-Known Member
Joined
May 16, 2012
Location
bedford va
Looks like I'm going to have no choice but to do the set up drkelly did...if I run my tie rod on top of my high steer arm the tie rod will bust the radiator
If I run my tie rod below the high steer arm the tie rod either hits the front diff cover or will hit the steering box shaft ..
So looks like I'm gonna have a set of high steer arms for sale lol
 

Mac5005

Well-Known Member
Joined
Oct 19, 2005
Location
Rocky Mount
Looks like I'm going to have no choice but to do the set up drkelly did...if I run my tie rod on top of my high steer arm the tie rod will bust the radiator
If I run my tie rod below the high steer arm the tie rod either hits the front diff cover or will hit the steering box shaft ..
So looks like I'm gonna have a set of high steer arms for sale lol

My tie rod comes very close to radiator at full bump, and Pittman arm.

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