I know that there is a lot of debate over what lift is best, but my questions is what is the differences between a 3 link, a triangulated 4 link, a 4 link with a track / pan hard bar, and radius arms. Maybe if someone from one of the lift manufacturers (Teraflex / Evo / Full Traction / Currie) as far as what the differences are, why they picked what they did. Obviously all lifts are made with the same goals in mind, and I am sure each style has something that it works best for.

Just to make sure everyone knows I am not looking to start a debate between whose lift is best, but the actual science and technology behind the lifts.

 

mabe this is to broad of an answer but when they say 3 or 4 link it is where the axle is attatched to the chassis/frame. an example would be your 4 control arms

 

I guess I was kind of hoping someone would do a write up kind of like Currie did on the axles, only make it for the suspensions.

I know that each company will praise only their particular lifts, but when you look at books detailing suspensions they are usually hundereds of pages long, and not everything probably applies to the JK.

 

a 4-link with a track bar is what your jeep comes with factory. it is a good design and one that can be enhanced with adjustable control arms and joints that allow for a greater degree of rotation.

both a 3-link and a triangulated 4-link rear design will allow you to achieve a greater amount of flex and with less bind. if you can get a triangulated 4-link to work, you can run it without the use of a track bar as the geometry alone will keep your axle centered under your jeep. for flex, a triagulated 4-link or even tri-link upper design is optimal but due to the location of the gas tank, it is also just about impossible to do on a JK without significant modifications.

up front, pretty mucht the best you can do is a 3-link setup where you basically run only one upper control arm. however, a track bar is still needed with this setup.

 

this is not such a bad idea and if i have some time, i will try to work something out with diagrams and all

 

i agree, it would be nice to see someone do a write up on the pros and cons of the different designs.
i am NO expert on this, and i hope people chime in on my comments and correct me if/and where neccessary....

so, for the most part it all boils down to what you want to use it for. extreme rock crawling vs: mud and desert racing....do you trailer, or do you run it down the highway.....and then there is always...what do you want to spend...

putting radius arms with a track bar is rather inexpensive compared to modifying a stock or semistock vehicle to a three link or triangulated four link. Then again, a three or tri-four link has alot better wheel and driveline alignment than a radius arm setup, but clearances for tires and suspension travel get more involved. exhaust (and other items) generally needs mod'd and you will find the tires rubbing the inside of the wheel wells easier.

if you never leave the highway but want to run the big meats... a four link with trackbar will keep the axles right where they need to be... and in the rocks where "true" wheel alignment isn't critical... it can perform very well too... even more so with coilovers. but if you are doing higher speed in the desert with a trackbar, the axles will be shifting laterally during extreme suspension travel... and that "could" get exciting too!!

 

I could truly talk about this subject for ages, I will not get into what is better or not because they all have their inherent characteristics. One 3/4 link can work great and the other could not, same goes for radius arm and everything in-between.

I will try to give you the general Cliffs Notes of terminology and some, not all, of their characteristics.

“3-link” and “4-link” in its most general term refers to the number of mounting locations on the axle or frame although most typically it refers to axle locations.

Triangulated 3/4 link: Triangulated 3/4 Links systems infer that one set of linkages, whether the upper set or the lower set are mounted on the center of either the axle tube or centered in-between the frame, where the other, opposite set of links, if uppers are centered then lowers are relatively parallel (most are slightly triangulated in the opposite direction) to the vehicle and vice verse. By having one set of linkages triangulated, when the axle cycles up and down it stays perfectly centered from left to right. By doing so, this increases the vehicles stability (compared to trackbar versions) throughout its suspensions range of motion.

3/4 Link with trackbar/panhard: 4 link with trackbar is what the JK has from the factory. It refers to 3/4 mounting locations to the frame and the axle with an additional linkage that mounts parallel to the axle or perpendicular to the vehicles frame, which is called a trackbar and panhard bar. Since the 4 link arms are not triangulated, the vehicles axle is not fully constrained without the trackbar. Its purpose is to constrain the axle from motion in the perpendicular direction.

Although the triangulated and trackbar versions essential purpose is to constrain the axles motion in the left to right direction, the major difference between the two is the motion of the axle in the left to right (driver to passenger) or vice versa throughout its cycle. Since the trackbar is an additional linkage mounted parallel to the axle tube, it pushes and pulls the axle, forcing it to move left and right through its vertical cycle, the triangulated version keeps the axle completely centered throughout its vertical cycle.

Radius arms systems have two linkages with two mounting locations to the frame and typically 4 mounting locations to the axle with the addition of a trackbar just as stated above. Radius arm systems, when done correctly have the ability to maintain drive angles that are perfectly in phase and little to no drive shaft plunge. From a pure geometry standpoint the disadvantage to this type of system is the loss of castor throughout its cycle although this is a tradeoff to drive phase angle.

There is so much more to suspension development than 3/4 link, triangulated, not triangulated, radius arm, etc. All that these terms imply is a suspension systems ability to constrain an axle in all directions which all these versions do. There are so many other much more important characteristics (which I will not get into) that actually make a difference in a vehicles ride and performance, such as roll center, anti-squat, anti-dive etc, which can all be changed and adjusted with advantages and drawbacks throughout a suspension systems development whether it is a 3/4 link, triangulated or not or radius design.

EVO…