Triangulated 4-Link | D21 Drift Truck - Ep. 19 

Don’t sell yourself short… this was my first go at it. Just took my time.

Yep... I'm predicting he's going to be sorry he didn't use heim joints when the dreaded suspension bind is more than he accounted for.

Thanks! I assure you it’s not on purpose. Haha I try to make content and something always seems to pop up. Just the way it goes I guess.

That’s good to know. Thanks

Haha, I have a nice set of Mitutoyo calipers with my other precision measuring equipment in my closet upstairs. Those cheapy plastic ones are my “bang around” quick reference calipers.

Thanks! All is well indeed.

Unfortunately the stock tank would interfere with the upper link quite a bit.

Welcome back buddy!

Thank you. Keep truckin!

Well, I’ll try to help clarify. I know you’re legitimately wondering like I was at first. Also, I love these types of posts. This is what helps people learn. Please don’t delete it. Lol That would only be true if one end on each upper link was stationary. If you look at the links, both ends have bushings. Both ends on all links move. There are 4 links total with 8 independent points of movement. I presume you’re thinking that only one end moves and that they travel on their own respective arcs. Meaning that the right upper link and left upper link push and/or pull against each other during operation depending on arc lengths. That’s not the case. Having 2-points of rotation on each link eliminates those arc tendencies. There is, however, a slight centering force in relation to the axle… That’s kind of the point of a triangulated 4-link. As the suspension is under force, it helps center the axle ever so much. That’s why triangulated 4-links do not require pan-hard bars or stabilizer bars like parallel 4-links. The upper links split the angular difference allowing side to side and front to back stability. The movement doesn’t chew up bushings because the axle is free to be where it needs to be under the truck. That’s why it’s so important to measure everything correctly. That axle is going to sit where you put it in relation to the bars.

Here’s a book by Max Fish on 4-link geometry that explains it much better than I can: books.google.com/books/about/Air_Suspension_Design_Book.html?id=-2ESzgEACAAJ

It would be the same. You could use a mustang 8.8 with the upper mounts already built in, but the explorer rear has bigger axle tubes and 31 spline axles. You could change the mustang axles though

This is sort of difficult to explain concisely on a reply post, but I will try my best, as far as I can understand. I'm always learning too! The lengths of the upper and lower links are different, but since they are able to rotate at both ends, it allows the diff to move up and down without the twisting effect. Eventually, you would run out of travel range starting with the shorter links first, but that would be over a much larger distance than this particular suspension would ever articulate. If this was an off-road build, meant for massive articulation, then the design would be different. As for the triangulated (angled) portion of the setup... The upper links control the track of the rear end due to them being angled. There's no need for a panhard bar on triangulated setups because the side-side force is counteracted by the upper links. Now, if it was a parallel 4-link, that's a different story. Because there's not counteracting force from either of the links, you would need a panhard bar that would redistribute that force accordingly.

You are right the diff has to rotate because the arc of each control arm is different notice he did not put an angle finder on the flange and cycle the suspension.

You’re almost always going to have a smoother ride with independent suspension. No question. There’s more independently moving parts to assist in adapting to all the variable road conditions. The more independent points of articulation, the more absorbing capabilities you have. That’s why IRS is superior in many ways to a standard live axle. For drag racing and off-roading, this change a bit. You sacrifice certain comforts to gain strength and linear traction.

Nope! Truck drives just fine. Zero pinion angle issues. I actually assumed the same thing, but I put my digital angle meter on the truck a long time ago, unhooked the coilovers, and ranged the suspension 14” and the pinion angle remained the same.

So… I built a 1UZ Toyota pickup years ago, and a buddy helped me fab up a similar triangulated setup. I really enjoyed it. It was predictable and simple. It definitely never felt like the axle was moving around. Haha I think that’s the importance of having it triangulated in the first place. The input force is cancelled out by the opposing side. The reason that there are different types of 4-link is due to fitment, space, and articulation requirements. They all effectively achieve the same result. Triangulated is the simplest, but also requires the most room to properly function. On another note, the only sketchy thing about these little trucks is the flanged axles versus having a nut/hub combo. Thankfully nothing has ever happened to my personal trucks, but it was always in my mind. [Snap! Wheel and broken axle come flying off the truck… 🤣]

A lot of folks think this for some reason. However, that’s not how this actually works. You’re under the assumption that the bushings and links move together inside the permanent welded on mounting brackets. When in reality, there is a metal sleeve in the bushing that sets the nominal distance for “squish”. The welded mounting points and bushings remain 100% stationary, while the link rotates on the bushing during articulation. The link is the only part that can move up or down. The bushing does not move with the link. If you look closely, you’ll notice the zerks fittings and how they distribute grease to the outer bushing side of the internal bushing. The bushing and metal sleeve are not designed to rotate hints why the grease doesn’t lubricate the inner sleeve. The bushings have to compress in order to add torsional resistance. Also, heim joints wouldn’t work at this angle due to convergent geometry. It would toss instant center out the window.

Hopefully good things. Haha

Thanks! I can’t wait to just beat the hell out of this thing. Tired of looking at it, just want to drive it.

Easiest way is to hop on IG and lookup Beebani Customs (Jason Pope). He doesn’t have a site to link.

@@IvelLeCog I work in construction.

@@Inner_Sanctum Nice, love the trades. Am a plumber myself

Wheels: 17x9 +0 Tires: 255/40r17

Thanks!

QA1 Coilover Bodies: DS401 QA1 Springs (Front): 9HT450 QA1 Springs (Rear): 9HT250 I have since switched springs. I’m now running 9HT650 up front and 9HT450 out back.

We don’t really have anything to sell off the engines. Chris owns 1, I own 1, and we have one spare that we’re building. Sorry.

Nope

@@Inner_Sanctum feel free to Google "parallel vs triangulated 4-link"

@@vincentking8267 your assumption is a very common misconception for folks. What you’re saying only makes sense for a singular point of rotation on a link. Meaning one side rotates while the other remains stationary. That not how this works. Both sides of the link rotate freely over the bushing therefore there’s no change to pinion angle during articulation. Also, the difference in length is important for instant center. Please feel free to Google.

@@Inner_Sanctum you can't get an instant center on a parallel 4 link because the 2 plains will never intersect, hence the term "parallel". Instant center references a triangulated setup. Which you had a kit for.

@@vincentking8267 that’s what I am talking about (triangulated). My setup is a triangulated 4-link that requires instant center. You’re assuming there’s a difference in arc length therefore there’s a change to pinion angle. What I am saying is that there is no arc length in this range of articulation because the link is able to rotate at both ends. Meaning when the axle moves up, it is able to remain in the same fixed position because there is no fixed point that makes it rotate creating a pinion angle issue.

I bought this kit particular kit from Jason at Beebani Customs. Pretty much had to modify everything in some way, but it ended up working out okay. Definitely would have saved the money and built my own knowing what I know now.

Depends on the joint I’m welding. I almost always put a ~45 chamfer/bevel before welding certain joint types. The inside corner joints and heavy lap joints on the upper mounting plates have plenty of penetration since I run the machine hot with a smaller .30 wire. The link mounting tabs on the axle third member absolutely have bevels. Most of my welds have bevels.

They are “Camco” RV stack jacks. You can get a set of 4 on Amazon for ~$35 shipped. I then went to Home Depot and purchased a 4’ stick of 3/4” all-thread and some 3/4” nuts for adjustability. Lastly, I cut (4) 1’ pieces from the all-thread and assembled. Viola!

Thanks! I would kill for another 620. I should have never sold the one I had. Yeah, that ports-band is becoming more useful by the day.

Stock D21 rear end with the Beebani dual caliper brackets and 2002 Honda Passport V6 AWD rear rotors.

Texas all the way!

I can look through my VH parts bin this weekend. I have another VH all tore down for spare parts.

@@Inner_Sanctum Dude that'd be sweet! No rush, but lmk.

It’s actually the weaker 10-stud 3.54 H190 with rear ABS. 97 was a weird year. Yep, I have a Dakota Digital signal box that I’m going to wire up to the ABS sensor and use as a VSS for the speedo. The pinion toner used is perfect for this kind of setup. I would like to swap over to a H233B at some point…

@@Inner_Sanctum I am working on H233B right now for my 1977 620. I blew the h190 years ago with a stock sr20det on 13lbs (T25).

@@Zukuri620 oh yeah, I’m sure it won’t hold together long. Just need it to survive long enough to shake it down.

Thanks man!

Thanks Gill. I bet that RB rips! Here’s that info: Wheels: Level 8 MK6 17x9 +0 (6x139.7) Tires: Federal RS-R 255/40r17

@@Inner_Sanctum thanks mate it's my mums old phone so it comes up her name .my names Scott gitsham ..cheers for the info re wheels .. I love the set up its so clean ..great videos

Thanks!

Thanks! I purchased the stands off of Amazon for ~$35. They are listed as: “Camco RV Jack Stands”. Then I just pulled the jack’s leveling post out and replaced it with 3/4” all-thread from Home Depot. Then I used nuts to level and lock everything.