Why Does a 2-Link Rear Suspension Limit Articulation?

First off, we should take a moment to clarify that a GM style, truck trailing arm (the rear suspension used in NASCAR) is not the same design as the 2-link that is commonly used in the air suspension industry.
The 2-link that we are discussing in this video is the design where the front points are typically bolted into the factory leaf spring mounts. It should also be noted that ladder bars are also a type of 2-link that has similar binding issues that are inherent to the design.
This particular 2-link variant is a very common rear suspension on bagged trucks and is well known to have no capacity for articulation (one wheel up and one wheel down). This binding is caused by the links not being able to pivot independently from the axle. Essentially, if you put the axle on the ground and bolted the two links onto the axle, you will have created a large, stiff "U" shaped part that will resist any pivoting where the links meet the axle housing. Whereas, a 3-link or 4-link, which are attached to the axle housing with bushings or heim joints, will allow the links to pivot up and down, not affected by the other links in the system.
As always, there is a lot more to it, but this quick video should help clarify things a bit.
Book order page - www.airsuspensi...

[@markfortin421]

Well...they say it's never too old to learn...and at 72 I'm still building cars, and Thanks to you, I'm learning stuff that I knew the basics of...but not the specifics.
Thanks!! ✌😊

[@MatthewScott]

The best content and knowledge for suspension design. Get the book. You'll never regret it and learn a ton from it. I did!

[@reynaldopadilla7420]

Do they go over suspension in general?

[@skinnydipper3493]

Interesting video. First time I've seen them. Will definitely look at more.

[@genoory5090]

This is something I plan on doing to my 2011 ford ranger,,but except trying to make articulate more & flex when I'm off roading etc

[@chansemiles7439]

Realize this is an old video but I have a question. Would one be able to build a 2 link and use Heim joints as the front pivot point?

[@joesmoke9679]

They would have to be right Before the trailing arm meets axle mount..

[@davidrutledge6033]

Awesome illustrations on the descriptions and very informative can't wait for the truck arm video great videos keep up the great work

[@Kmaaq]

Hey, way less suspension components and your axle is now a sway bar too. All in all great weight savings!

[@bananaman2184]

You might be onto something...

[@gotj]

Hello, in your shop I can't choose Spain as destination for shipping. Can you fix that please? Thanks.

[@coryholbrook4643]

Never seen a 2-link used anywhere before.

[@BOOT]

Don't think I've ever seen a 2-link as pictured, there is always a bushing of sorts at both ends so it's not trying to twist the axle as you showed. Ladder bars aside of course

[@psk5746]

Agree. Please list a car that has this design

[@tesznye6992]

@@psk5746 suzuki ignis

[@psk5746]

@@tesznye6992 thank you

[@richardschofield2201]

Don't land rovers use this type of suspension at the front?
The arms are called radius arms.
You still need a panhard rod to prevent side to side movement.
I've seen huge amounts of articulation on land rovers (granted more from the back that uses A-frame)

[@LeeOwen-g9h]

The Range Rover P38 had this setup at the rear with bushes at the axle end and a special shape arm to allow flex, works really well offroad and simple

[@charlesdavis7441]

But dragstrip would be okay, right?

[@17cepane]

Would a ladder bar setup work the same or is there articulation present?

[@pedanticpublishing8881]

A traditional ladder bar would do almost the exact same thing as this is showing.

[@loganshotrod4x464]

There are so many things to consider when designing & setting up suspension...

[@396M21]

When is the truck arm video?

[@thakormihir4875]

Thanks for video

[@elmodhka420]

Like your videos a lot very helpful . Can you please do one for the truck trailing arm with wats links. Thanks

[@pedanticpublishing8881]

Our book covers both of those subjects, but we actually have a Watts-link video already - th-cam.com/video/xWl3Cd7edgM/w-d-xo.html

[@sriharivaila7276]

Wt is the meaning of articulate

[@mattdavis9601]

How the axle moves (flexes) in response to terrain.

[@runninlow9609]

Any idea when the book will be done? I feel like i paid for it years ago.. lol.

[@pedanticpublishing8881]

We are still working on the book, but have no release date yet. All we can do is keep on it until it is done.

[@felipelimon2484]

How's the progress of the book now

[@felipelimon2484]

I would like to buy

[@wesconecustoms]

@@felipelimon2484 buy it, they started shipping this week

[@MrDejast]

Only true on that solid axle, not on independent rear suspension.

[@Iammastercheif1]

Right. The title states 2-link, which the type of solid axle displayed. It makes no claims for that to be true of any other setup

[@psk5746]

MrDejast, no kidding