DIY 1 Ton IFS Long Travel

KevinK

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#61
OK, so say I know someone who wants to start fucking with designing a cantilever (actually a bellcrank) rear leaf-sprung suspension, but they're kinda dumb. They have some drafting experience from high school - like pencil and paper and rulers type of drafting (this fucker's old).

What software should this cheap ass try out first?

Of paramount importance is visualizing the arc movement and measuring distances of axle movement relative to shock shaft movement.
 

AssBurns

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#62
OK, so say I know someone who wants to start fucking with designing a cantilever (actually a bellcrank) rear leaf-sprung suspension, but they're kinda dumb. They have some drafting experience from high school - like pencil and paper and rulers type of drafting (this fucker's old).

What software should this cheap ass try out first?

Of paramount importance is visualizing the arc movement and measuring distances of axle movement relative to shock shaft movement.
I'm using Fusion 360 on the education license. Just gotta say you are in school and it's free to use. Took me a bit to figure out, but after watching a bunch of youtube videos and googling all the questions I had, I was able to figure out how to do most of the basics.
 

KevinK

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#63
I'm using Fusion 360 on the education license. Just gotta say you are in school and it's free to use. Took me a bit to figure out, but after watching a bunch of youtube videos and googling all the questions I had, I was able to figure out how to do most of the basics.
Thanks! Looks like I'm back in school.
 

AssBurns

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#64
Also @KevinK, what is the difference between cantilever and bellcrank suspension? Looks to be same from what I can see on a google image search, but I could be missing something.
 

KevinK

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#65
Yeah, that's kind of the problem in researching or designing a bellcrank. Everyone pretty much uses the same two terms interchangeably, but they're different. It basically comes down to the arrangement of the axle, pivot and shock connections.

bellcrank - axle, pivot (static fulcrum), shock

cantilever - axle, shock, pivot (static fulcrum)


A bellcrank can maintain 1:1 axle to shock motion ratios, but a cantilever cannot.

Bellcrank images:







These are cantilevers. Basically a standard linked setup with coils or coilovers



This is also a cantilver since it pivots at the left, has a shock, and then the axle connection out at the end

 

AssBurns

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#67
Yeah, that's kind of the problem in researching or designing a bellcrank. Everyone pretty much uses the same two terms interchangeably, but they're different. It basically comes down to the arrangement of the axle, pivot and shock connections.

bellcrank - axle, pivot (static fulcrum), shock

cantilever - axle, shock, pivot (static fulcrum)


A bellcrank can maintain 1:1 axle to shock motion ratios, but a cantilever cannot.

Bellcrank images:







These are cantilevers. Basically a standard linked setup with coils or coilovers



This is also a cantilver since it pivots at the left, has a shock, and then the axle connection out at the end

somehow this didn't attach:

Ahh that totally makes sense now. I've actually never heard anyone ever call it a bell crank before. It's always been mislabeled as cantilever or lumped into the pushrod category.
 

KevinK

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#68
Ahh that totally makes sense now. I've actually never heard anyone ever call it a bell crank before. It's always been mislabeled as cantilever or lumped into the pushrod category.
Ah yeah, pushrod for sure. except when the rod isn't present and the crank attaches to the axle, but same same.
 

Dezert4Runner

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#69
I’ve also heard of it referred to as a mezzanine arm setup. Looks the same as cantilever to me but I’m no fabricator :noidea:

There was a blue FJ Cruiser with one that came up into the cargo area years ago built by a big shop that was nice but I forget who made it. SDHQ?
 

KevinK

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#70
I’ve also heard of it referred to as a mezzanine arm setup. Looks the same as cantilever to me but I’m no fabricator :noidea:

There was a blue FJ Cruiser with one that came up into the cargo area years ago built by a big shop that was nice but I forget who made it. SDHQ?
Yeah, this one. It's pretty bad ass. They were building it around the time I first started talking to them about building our Tundra, and I got to finger bang it in their shop. 10/10 - would bang again.

 

AssBurns

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#72
Anyone have or know where to get a CAD file for '05+ F250-F350 Super Duty unit bearings? Grab cad has the F450 model for 99-04 Super Duty's, but I want to use 05+.

1570478453647.png
 

AssBurns

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#73
✔ First step to 1 ton IFS. Just ordered some '05+ Super Duty Unit Bearing Cups from S&S Fabrication. Time to pick up a AAM 9.25" Diff and some unit bearings so I can start drawing some things up. First I gotta see how I can stuff a big ass diff up front, then I can work on spindle design. Once I get a spindle design and mounting points figured out, I can then figure out the arms. This probably wont go anywhere anytime fast, but at least its a start.

1570555553601.png
 

AssBurns

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#74
Got the CAD file for the 05+ Super Duty Unit Bearings I was looking for. These things are beef! Now I see why people want to use 05+ Super Duty axles. Everything is beefy on these. The CAD file I have is from the F550 "Super 60" axle which is basically a beefier version of the standard 05+ SD axles. The differences I found are the following: (none of this is really related to my IFS setup, but just info for people looking)
- F450/550 have 10 lug unit bearings vs 8 lug on F250/350 (Everything else is the same)
- F450/550 have 1550 U-Joints vs F250/350 have 1480 Joints
- Due to the larger joints, it moves the joint pivot further out in the knuckle. So the knuckles are larger on the F450/550 axles.
- The "Super 60" has a 10" ring gear whereas the standard F250/350 axles get the standard 9.75" ring gear.

I think that's it.
If you want the CAD file, let me know. I can attach it once I change the allowed file types on the forum.
 

AssBurns

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#75
I've still be researching ideas on which diff to use and some pro's and con's of different diffs. The idea is to be able to handle 40's (not necessarily that I will be running 40's, but I want the strength to be capable of it)
The top contender is the GM 9.25" AAM IFS. This one has an aluminum housing (good for weight, bad for strength). It's a high pinion and has reverse cut gears which means it has good gear strength and durability. Has gearing options up to 5.38 gears (Which is what I want) and has locker options (I'll be going ARB either way, but it's nice to see options and support from multiple manufacturers)
There is also the Ford 9.75" IRS. This one looks to be cast iron, which means more weight but a stronger housing and less chance of deflection or a case exploding. Doubt this will be a major issue, but if I go with big tires and bigger motor down the line, this could end up being something to be concerned about. Because this diff is a rear diff and low pinion, it would mean that the gears would be riding on the coast side of the gears. This might not be a huge issue since there are a ton of guys running low pinion 9" diffs up front without any issues. The diff is centered which means I wouldn't have to worry about a custom length ADD tube. Uses C-Clip axles. Not something I would want to deal with.

So the benefits I'm really seeing with the 9.25" AAM is:
- Off centered = push the diff higher up potentially
- Lighter weight cast aluminum housing
- better gear options (5.38)
- reverse cut gears = potentially stronger
- Doesn't use C-Clips to hold in the axle shafts.

Benefits of the Ford 9.75":
- Centered = narrower diff (more travel possibly)
- Low Pinion = more room for the driveshaft to fit under the oil pan.
- No ADD tube to narrow down and less custom parts.
- Cast iron = stronger housing
- larger ring gear = same as D60.


GM 9.25 AAM IFS

1570755484741.png

Ford 9.75" IRS

1570755398446.png
 

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