Shackle Flip design for SUA LT

Starting another build thread here with a little Tacoma re-engineering. I purchased the Dirt King SUA long travel kit for the rear of my DCSB few months back. I love the kit. The build quality is great so I have no problems with dirt king whatsoever. I have many of their products. I just have a little beef with how SUA long travel conversions are commonly built with inverted shackle designs. Inverted shackles just don’t cater to crawling. They are more for dessert race which is fine but why not have the best of both??


After install of the DK LT I was a little disappointed with the rear ride height. I had a 3” CO lift front/ 3” 8 leaf pack SOA rear, with a little rake, u bolt flip kit, etc prior to the install and enjoyed my ride height and ground clearance. That’s how I like the truck to sit. After the install of the LT kit, I ended up with only about 1” lift in the rear with 3” in the front. I couldn’t deal with it. Too much sag and not my style. My options were lower the front end to match the ride height of the rear or do something about the rear but the question was how do you increase the ride height of a SUA set up? I consulted my long time buddy here in Reno who owns a leaf spring shop and he gave me some ideas.

1. Shorten the 8.2” DK shackle to a 7” shackle to gain 1.2” of ride height but loose articulation and risk spring inversion /buckling. Bad day.
2. Go back to SOA. Too much digression.
3. Switch to a shackle flip kit. Follow natural arch of the leaf spring compression. Increase ground clearance. Have adjustability to spring rate and ride height by means of moving a single bolt. Remove need for hangers that hang 10” below the frame!!!

Option 3 was obviously desirable but the only problem became finding a drop in shackle flip for a LT. JD fab makes their LT kits with the shackle flip off the shelf. I probably would have gone this style of LT had I known about JD fab prior to learning everything I know now. I quickly knew my solution had to be custom due to the leaf spring spacing of the DK kit and I really didn’t want to remove the rear axle again and cut off/reweld spring perches, etc.


So I took the next three months of spare time drawing, modeling, ordering medal, ordering custom laser cut pieces and fabing. Finally got to the point of installing it on the truck last weekend and I gained 2” ride height without sacrificing spring inversion or ride quality simpky by changing the arc path of the spring compression. The shackle is in the forward most position which is least likely to buckle and has the lowest ride height difference if the three pre cut mounting holes.


I also have more adjustability to lift the truck further but I would risk spring inversion. The only way to do this safely would be to swap the 2” bump stop for a 4” bump stop and limit up travel. By another 4”. Not ideal but could give you the desired ride height. I also have forward and reward adjustability on the hanger to stiffen or soften the spring.


Total cost of project:$500

CNC laser shop: sendcutsend

New shackle length: 9” (8.2”ish on the DK)

Material: 1/4 mild steel for everything (will switch to 1/4” chromoly on version 2.0 if I have warpage issues with current design.


Below are my models, drawings, fab pics, etc.


Happy to answer any questions out there of guys/gals dealing with the same issue.

I can’t be the only guy disappointed with ride height on LT daily drivers.

 

Solidworks model of original design. Drivers side installed.

 

How the truck currently sits. Very pleased.

 

Pictures of truck with DK LT SUA kit prior to my re design.
The DK kit yielded about 8.5” up travel and 8.5” down travel for me.

With redesign, I’m yielding approximately 10.5” up travel and 6.5” down.

 

Dude! Thank you for posting this. I've got the DK LT kit up front, and have been doing a lot of research to approach the rear end(stock w/ AAL). Between keeping it leaf sprung or linking it, and all the trials and tribulations that come along with them. I've decided to stay leaf sprung for the time being, trying to keep it reasonably budgeted/functional for daily driving.

THIS was my biggest question. How to keep my ride height, but go SUA with a shackle flip. My conclusion was I need to have about a 30 degree shackle angle at ride height for optimal travel/effective spring rate. Ideally some adjustability to get that sweet spot once it is all put together.

So my questions: What leaves are you running? Deaver?
How long is your actual shackle you had made?
Did you design both sides or were you able to mirror them for the laser cutters?
How did you KNOW you got it right when designing?

I am a metal fabricator, auto technician(trucks & jeeps) and I dabble in Fusion360. I have yet to experience the wonders of solid works but when I get better at 3D modeling I plan on getting it. So my plan is to build these myself. Working off a cad drawing would be extremely helpful so I may take the time to design them myself. I also know some shops with all the fancy equipment so maybe they'd help me out. We shall see. Either way, would love to know more about your design process.

Again, thanks bro. This really helped me confirm that I am asking the right questions. It seems to be a very specific question with very specific application. I've asked around to the knowledgeable people I know and no one can quite get what I am trying to achieve. So very helpful.

Cheers!

 

Hey man, I am glad this post helped anyone because like you said, it is a very specific application to a specific LT kit.

Linked with coilovers would be awesome. I have received a lot of questions why I didn't just go that route for all the fab work I was already doing.

Answers to your questions:
1. The leaves are Deaver H70HD.
2. The shackle length is 9" eyelet to eyelet. I think 8" -12" shackles are pretty typical. I am contemplating a 10" to 10.5" for the articulation I want. This would lift the rear a little more.
3. Both sides were designed as symmetrically as possible to minimize the number of pieces. The shackles are fully symmetric, hence the visible slot in the side. I never filled the slot back with weld because I was just trying to get this done. Everything is a tab and slot design to aid in assembly but some unused slots are visible if not filled in with weld later. Most pieces on the hanger are symmetric, however, because our frames our tapered toward the rear, the hood piece of the hanger is actually two different pieces side-to-side. They hood is identical when they are laser cut but they get bent in opposite directions.
4. The short answer is a significant amount of measuring then drawing it. I first had to reverse engineer the LT kit i had installed. I found a frame drawing online and started there. The shackle length was approximately 8.2" and the leaf spring separation was 46" on center. From here I was able to design everything around that. Most importantly I had to draw the original angle of the shackle when the leaves where fully compressed and fully extended. My goal was to design the shackle flip to have the same eyelet locations when the leaves were fully extended or fully compressed and bound by the shackle. By doing this, I knew I wasn't exceeding what has already been designed in the original kit. This pic below will probably explain it all.

I hear you with CAD. I prefer designing in CAD myself then convert everything over to solidworks as a proof of concept and fitment. Good luck and let me know if you have any other questions.

 

Update:

I adjusted the shackle down to the lowest setting because I added some weight back to the truck for hunting season.

added weight:
RTT
Tire carrier
Full sized spare
Rotopax 2 gal
High lift
Tool box
Traction boards (that I have never used in 5 years and am convinced are just for looks)
Prinsu top rack on the camper shell.

Not sure what that all adds up to. It’s got to be significant, maybe 350 lbs.

The truck still has some lean but it’s close to level. In the next few months I am going to experiment with longer shackles to solve the ride height issue further.
Overall, I am still very pleased. The lean would be 3”-4” lower in the rear with all the weight and with the original hangers and shackle design which would have been unacceptable.

 

I’m running the JD sua kit. Extremely satisfied with it. I have their rear shackle hanger at the most forward position , and the shackle in the most downward pivot hole (they give you 6 options for setting up hanger/shackle). With the regular non HD 62”deavers I’m about 9” up-travel and 8” down travel (running rear cbi high clear steel bumper and stock tailgate). No limit straps needed, spring and shackle limit full droop. Another major reason I went with JD (besides inverted+ Uniball shackles ) were the shock towers made for 14” shocks. They essentially don’t interfere with the stock bed space (although u need to cut tops of inner fenders). Pulls just as much travel as any of the 62” kits yet don’t need bed cage and 16” shocks , almost zero bed space loss , uniball shackle pivot, and inverted non “boat anchor” rear shackle.

 

I have always been curious of the JD SUA, it definitely seems like there are a lot of pros to the JD kit. How do you like the uniball shackles? I am curious if that effects how the truck handles on the road.
Also, how is your ride height with the regular non HD 62" Deavers? If I was having ride height issues, you must of been lower, unless maybe you aren't running any added weight. Not saying that's a problem to be lower, I just didn't like how mine sat.

 

The ride height is a little on the “low side “ after off roading a few 100 miles . I have a 3rd Gen double cab 4x4 auto, stock bed and tail gate with a cbi steel rear bump. Not a lot of weight , but enough to sit at 1/2 up travel and 1/2 down travel with these non-HD 62s. In principle it’s not ideal as I want more uptravel for higher speeds but in practice it’s amazing. Never bucks or bottoms out in the rear , and the ride is nice and soft. I’m tuning fox triple bypass and icon hydro bump . This combo lucky was absolutely dialed perfectly
not sure how the uniball shackles effect body roll but if it does it’s hard to discern either way just because it’s LT and will have body roll regardless of bushing or uniball.