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Full Hydro 50° steering 05+ SD 60

Spotty Wheeler

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Feb 1, 2021
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Building out a 05+ SD 60 for my YJ project and I've ran into a snag. I'm going to be running full hydro, 43's on the Motobilt SD truss and TMR Weld on High Steer arms. Talking to PSC on the phone, they recommend a 2.75" Diameter ram for 43's, however they don't make one in a 10" stroke, only a 2.75x8". They make a 3x10" and a 2.5x11 or 9" set up that I could have limited. However, I'm not sure that 2.5" diameter ram will hold up to 43's and trying to fit the 3" Ram in the Motobilt Truss with skid kit might be tricky. What kit is everyone running in combination with 1550 U-joints to achieve that 50° of steering on your Super Duty Axles?

photo45463.jpg
 
shorter steering arms or does that not clear things? limited 2.5x11 would be easy enough. what is the shaft diameter difference between the 2.75 and the 2.5 cylinders?
 
I think if you go around 5.75 inches from cl of upper ball joint and cl of heim/ tie rod joint is where you need to be for an 8" stroke ram to get full lock, but I'm not sure if that will go all the way to 50°or not. I'm sure by modifying where your tie rod joint attached you can make any of those stroke rams work.

Eta; I'm also not sure if your weld on arms can change the tie rod mount location...:homer:
 
On my super 60, 5.5" from axis of ball joint to drag link pivot point turned 45* with a 8" cylinder. The hard stops had not much more than an air gap. The angle also depends on where you measure from due to caster and Ackermann.
The TMR and Artec have long arms so you will need a 10" to get close. JHF arms are shorter and needs a 10" to hit 50*
The more angle you add the more cylinder force you need.
High wheel offset can also require more force to throw them around.
The pump pressure and flow can set the cylinder size as well. Too large of a cylinder will slow it down and not be responsive enough.

Theoretically:
45*= 8" on 5.657"
45*= 9" on 6.364"
45*= 10 on 7.071"

50*= 8" on 5.222"
50*= 9" on 5.874"
50*= 10" on 6.527"
 
While we are talking 50*, what axle shafts are you running to get that much? Clearanced 1550 stock shafts, Branik shafts? I know that RCVs cant get that much.
 
I have a 2.5x8.75" ram on my buggy with 43s.
I wish I went bigger when I'm super bound up in the big rocks. At that time you can feel that you're forcing to turn the wheels.
But that's a fairly rare occurrence since I don't rock crawl much (I'm more a point and shoot/bouncing guys). Rest of the time it's super fine.

I am glad I don't have too big of a ram, since the pump volume that would be required to keep up with a fast steering at speed would be a problem.

Bottom line, I'd do it again, and for your particular setup, I'd get the 10" ram and limit it to your liking.
 
Bebop said:
I have a 2.5x8.75" ram on my buggy with 43s.
I wish I went bigger when I'm super bound up in the big rocks. At that time you can feel that you're forcing to turn the wheels.
But that's a fairly rare occurrence since I don't rock crawl much (I'm more a point and shoot/bouncing guys). Rest of the time it's super fine.

I am glad I don't have too big of a ram, since the pump volume that would be required to keep up with a fast steering at speed would be a problem.

Bottom line, I'd do it again, and for your particular setup, I'd get the 10" ram and limit it to your liking.
Click to expand...

any idea what pump pressure you are running at? that might be a "free" way to increase some force when you are bound up
 
Provience said:
any idea what pump pressure you are running at? that might be a "free" way to increase some force when you are bound up
Click to expand...

The thought crossed my mind.

I am running a basic PSC P-Pump so I think the relief is set around 1400psi (maybe more ?).
I'm looking into a Radial dynamics CBX (I know they can be set at 1800PSI, maybe more ?) but right now I'm planning for a rear steer upgrade too so I'll do everything at the same time.

I really don't encounter the bound up situation too often since I don't really do any heavy rockcrawling. I think I had the buggy to a point I couldn't steer maybe 2 or 3 times in 1 year. And every time it got solved by backing up and finding another line.
I'm not a Sand Hollow canyon killer or any of that. Having a big displacement pump that can deal with a 200/230cc orbital valve and turn the wheels fast is more important to me.
 
If it is actually 1400 PSI, you can definitely pick up some extra force going with a higher pressure. I stock pumps up to 1800 PSI on the CB-X but I also have options to move to a higher pressure adjustable external relief valve which I have done for a few setups. Any time you want to look at making the change to rear steer and pump upgrade, I'd be happy to help out.
 
A bump on this. With Barnes arms I'm at 8 inches from the TRE to the center of the ball joint. Using a tape measure held in place and turning the knuckle back and forth i'm looking at 11" cylinder just to achieve 45°. With the long arms I don't think I need as much force to turn the knuckles but PSC only offers a 3" diameter at 11" stroke.
 
If you do the maths cylinder working area works out better than leverage. I would take a larger shorter stroke ram over a smaller longer stroke ram. You'd have to get into some fairly long rams and steering arms to make up the difference you can do with cylinder area.
 
Ghetto Fab. said:
If you do the maths cylinder working area works out better than leverage. I would take a larger shorter stroke ram over a smaller longer stroke ram. You'd have to get into some fairly long rams and steering arms to make up the difference you can do with cylinder area.
Click to expand...
I agree, I was mostly hoping there were other cylinders maybe 2.5 with longer than 11 inch stroke. I already have these arms welded onto my knuckles, but knowing now how they would limit my steering with how long of a cylinder I would need I would have opted for different steering arms.
 
KB6Chris said:
I agree, I was mostly hoping there were other cylinders maybe 2.5 with longer than 11 inch stroke. I already have these arms welded onto my knuckles, but knowing now how they would limit my steering with how long of a cylinder I would need I would have opted for different steering arms.
Click to expand...
I’m at 42° with Barnes weld-on’s and a 10” ram, my shafts will supposedly handle 47° but with a 8.75 BJ to tie rod center I’m out of ram. I’m thinking of going with the American Iron knuckles and a 9” ram , here’s a CAD shot of the knuckle with integrated double shear arm.
image0.jpeg
 
That is interesting.
americanironoffroad.com

AI-8000 American Iron Offroad™ Ford Super Duty Outer Knuckle Set

Want a 2005+ Super Duty knuckle with double-sheer and hi-steer? These knuckles bring innovation and design to the stock knuckle at an affordable price. Casted, machined, and powder-coated in the USA, eliminating the need for additional machining, drilling, and tapping. Designed with added...
americanironoffroad.com americanironoffroad.com
 
greenlion said:
That is interesting.
americanironoffroad.com

AI-8000 American Iron Offroad™ Ford Super Duty Outer Knuckle Set

Want a 2005+ Super Duty knuckle with double-sheer and hi-steer? These knuckles bring innovation and design to the stock knuckle at an affordable price. Casted, machined, and powder-coated in the USA, eliminating the need for additional machining, drilling, and tapping. Designed with added...
americanironoffroad.com americanironoffroad.com
Click to expand...
Yeah , I like everything about them but the $1,400 price tag. The 6 5/8’ish dimension works great with a 9” ram and the double shear arms look stout. Now I need the correct pump to run a 3” cylinder , without sufficient flow this system would suck…lol
 
Those American Iron knuckles look like they have a shit ton of Ackerman which isn't really conducive to 50° steering. Just doing some back of the envelope calculations, it looks like they have proper Ackerman for a ~60-65" wheelbase :eek:
 
'84 Bronco II said:
Those American Iron knuckles look like they have a shit ton of Ackerman which isn't really conducive to 50° steering. Just doing some back of the envelope calculations, it looks like they have proper Ackerman for a ~60-65" wheelbase :eek:
Click to expand...
If making a knuckle from the ground up like that....I wonder why in the world they didn't take that into account (b/c surely they didn't design for a 65" wheelbase).
 
Sean said:
If making a knuckle from the ground up like that....I wonder why in the world they didn't take that into account (b/c surely they didn't design for a 65" wheelbase).
Click to expand...

Looks to me like thet just went up from the stock arm location, but due to the king pin inclination, which is a lot on the '05+ stuff, you effectively get more Ackerman the higher you mount the tie rod. The stock superduty tie rod mounts below the steering arm. Their knuckles look like it mounts pretty close to the same plane as the upper ball joint.
 
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'84 Bronco II said:
Looks to me like thet just went up from the stock arm location, but due to the king pin inclination, which is a lot on the '05+ stuff, you effectively get more Ackerman the higher you mount the tie rod. The stock superduty tie rod mounts below the steering arem. Their knuckles look like it mounts pretty close to the same plane as the upper ball joint.
Click to expand...
They alluded to me that these are really marketed toward full hydro in a double shear application which would put the tie rods like 4” below the upper ball joint plane if you chose to go directly in the center of the arms. The bottom arm is also I designed to let you mount a tie rod in the stock location in relationship to the axle tube centerline, the tie rod will go from below the arm to above.

The 6.626 dimension is supposedly what Ford uses on factory knuckles , I’ve eyeball guesstimated this and I believe it. My knowledge of determining Ackerman is very limited..like zero :laughing: so I’m all ears on learning more. Here’s a different view of these knuckles.
IMG_0905.jpeg
 
'84 Bronco II said:
Those American Iron knuckles look like they have a shit ton of Ackerman which isn't really conducive to 50° steering. Just doing some back of the envelope calculations, it looks like they have proper Ackerman for a ~60-65" wheelbase :eek:
Click to expand...
Agreed.
Lazy engineering in these. They just moved the OEM holes higher.
 
What jumps out at me is how you would get the tie rod tight. Obviously , there’s no taper hole. If you put the tie rod in the center of the arms with some spacers, would you clamp it by bending the arms a few thou? I don’t think cast likes bending. I guess you could make it a press fit and pound the rod end/spacer in. Wouldn’t that make it bend the other way? Maybe a sliding sleeve like on a alternator?
 
WaterH said:
What jumps out at me is how you would get the tie rod tight. Obviously , there’s no taper hole. If you put the tie rod in the center of the arms with some spacers, would you clamp it by bending the arms a few thou? I don’t think cast likes bending. I guess you could make it a press fit and pound the rod end/spacer in. Wouldn’t that make it bend the other way? Maybe a sliding sleeve like on a alternator?
Click to expand...
Use a reamer ar a tapered insert.
 
Looks like the just duplicated the SD60 tie rod mounts, which is a through bolt scenario.
 
Bullitt1 said:
They alluded to me that these are really marketed toward full hydro in a double shear application which would put the tie rods like 4” below the upper ball joint plane if you chose to go directly in the center of the arms. The bottom arm is also I designed to let you mount a tie rod in the stock location in relationship to the axle tube centerline, the tie rod will go from below the arm to above.

The 6.626 dimension is supposedly what Ford uses on factory knuckles , I’ve eyeball guesstimated this and I believe it. My knowledge of determining Ackerman is very limited..like zero :laughing: so I’m all ears on learning more. Here’s a different view of these knuckles.
IMG_0905.jpeg
Click to expand...
If you want the quick and dirty way to check where the Ackermann falls. Hold the knuckle straight as if they were on the C's and run a line from the tierod hole through the center of the ball joint hole and run it all the way beck to the center line of the rig. Do the same with the other knuckle holding at the width your axle will be. The distance where the lines cross is the 100% Ackermann line. Where that line falls compared to where the rear axle is is your Ackermann %.

There are other ways to play with Ackermann %, but for what we do, keeping the ram as tight to the axle as we can, we don't need to get into that.
 
Grendel said:
Looks like the just duplicated the SD60 tie rod mounts, which is a through bolt scenario.
Click to expand...
They’re available blank , a .750 hole or taper reamed on top or bottom . The engineer I talked to also said they could possibly push the hole span out to like 7.125 .
 
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