Taco Sauce TX Pro Build: Custom LT, 37’s, Tundra Axle Swap, and now a Back Half?

Probably 1 or 2 more test cycles to dial in the upper pivot location and it will be time to build the real shackles and pivot.



Looking like it’ll end up between 17.5-18” of clean usable travel with a 12” shackle at similar ride height as before. Longer shackle testing got me 19-19.5” of travel but the ride height was way too tall. By the time I moved the upper pivot to bring the ride height back down it resulted in the same travel as the 12” because The frame is in the way of gaining back the bump travel. Not worth the hassle of notching the frame to gain that little bit of travel. You want more than 18” of travel then don’t stay with leafs lol

 

Lookin good man! excited to see these beefy shackles.

you're axles are done btw. I didnt snag a pic.. but can tomorrow. Ya just gotta press in the studs.

 

Sweet! Was gonna text you and make sure you guys are open or available to pick up next Saturday.

 

ehhhh... IDK. I can be there.. but somebody else might need to be there to finalize it all. I dont have those powers.. lol

 

Ok ok. Well if you can ask that would be great. Worst case maybe I can PayPal you on Friday? You take care of the bill and just grab my shit and we can meet up somewhere near the shop on Saturday? Zuk is like 5 miles down chandler Blvd on the other side of the 101 for your shop so anywhere in that general area would work for a meet up. Well text next week and work out the details. I know they emailed me an invoice but I haven’t opened it yet

 

Cool. Yeah I'll see what I can do man! That works for me if it does.

 

Playing with computers for the new shackle designs while waiting for a few bits and pieces to arrive. It’s simple and definitely didn’t need the CAD for anything other than my personal practice. But still fun to mess with at times.

 

Looks good. I wish I had the know how to play around on CAD for projects. I can see where it would be very beneficial.

 

Would it be easier to not just do some tube or something like total chaos for the 1st gen?

 

A little yes and a little no. Building that style would be easier and a reason they do that style is the leafs on the first gen are directly under the frame usually. So the upper pivot either runs through the frame itself or sits on top of it. So the shackle needs to be able to straddle the frame. My setup the leafs are outside the frame so it makes things a little easier to build the upper pivot where the bushing is a part of the shackle.

Second thing is that with such a long shackle there is risk of a lot of side loading while trying to keep the axle centered under the truck in corners. To combat that I am going to do a shackle slider setup like this so that big flat surface is beneficial

 

Ryan, I am a little concerned with running an 18” long shackle and maybe you can clear things up. Due to the design of leaf spring suspension, it allows not only vertical movement, but also the unfavorable transverse or lateral depending on how you look at it. OEM suspension has minimal transverse movement due its shorter “links”; less arc in the springs and a shorter shackle. This is also dictated on where the axle is located in its range of motion. Let’s say you went from a 12” to an 18”. That is a 50% increase in length which correlates to a 50% increase in lateral force on your rear pivot due to the longer moment arm. I am not a vehicle dynamics engineer haha (I’m more involved in heat and mass transfer), but I feel that there is going to be a lack of stability at higher speeds due to more sensitivity to lateral forces. Maybe the shocks can somewhat control that as well, but I’m not exactly sure. Like I said, this isn’t my expertise, but wanted to express my thoughts.

 

Never mind, I saw your last post on how you are going to help mitigate it

 

Don’t you dare bring up heat and mass transfer haha that was actually a super interesting class but holy hell was it a tough one. Also not gonna run 18” shackles, that was just kinda a joke to get MAXIMUM travel out of the leafs. My mock up ones had holes for 10,12,14” lengths while I cycled and tested upper pivot positions. I was shooting for the 12” mark as that is a common length for this style of setup but a factory frame hole as a pivot point and 14” shackles gave me almost perfectly desired results and ride height so I’m gonna run with that one.

The “slider” will cover 7” of the shackle at full droop and up to 10” at bump in my attempt to keep it from hanging low off the frame as well so that long 14” moment arm is supported at least 50% of its length throughout its travel. And I will have an internal rib inside the shackle to help mitigate deflections. For reference that picture of the other setup is on a heavy bronco with 14.5” shackles and he’s been running that setup for a few years now. And if I do end up chewing through upper bushings then I can always have some machines or if delrin for additional support

 

Yeah my least favorite class back in school and somehow my career revolves around it haha. I couldn’t tell if you were joking or not so decided to give the information route instead of risking the chance of insulting you lol.

Sounds like a good plan. I guess you’ll see what happens when you start pushing it; all part of development work.

 

Yeah it was an interesting class but damn was it difficult. And I appreciate the concerns. I’m a recent ME grad looking for my first job still. I try to consider all the design parameters and possible failure points but sometimes you forget or don’t see something. Got a few friends that are engineers as well and I usually bounce ideas off of them as well as a buddy that used to build and race leaf spring trucks. He’s been my tour guide into design and how certain things will effect the ride. Also the one that turned me onto that slider to limit deflection (his buddies bronco)

 

I wish you the best of luck with the job search. Yup, you can only cover so much of the DFMEA solo; definitely beneficial to have some connections with experience.

 

Thanks. Kinda the worst year to be entering the job market. But I’m finally starting to see some job opportunities open up. But yeah, buddies that are into trucks/ bikes with various engineering backgrounds and a buddy that used to build race trucks are great sources for bouncing ideas around.

 

Picking up axles and diff tomorrow

 

Diff is back and in, axles assembled with new bearings and seals and all good to go. Just need to redrill brake rotors and I can work on brake lines and what not

 

Looking good man! How'd pressing in the studs go?