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Icon 4 link

42K views 85 replies 31 participants last post by  Aggie007 
#1 ·
Im thinking about buying a 4 link for the front of my truck.

Question is, are there any disadvantages when using these in drag racing or sled pulling applications?
For some reason I thought I read somewhere that they were not ideal for one of the above mentioned uses.


Do they reallly make that big of a difference in handling/ride during everyday driving?

Thanks
 
#2 ·
Im thinking about buying a 4 link for the front of my truck.

Question is, are there any disadvantages when using these in drag racing or sled pulling applications?
For some reason I thought I read somewhere that they were not ideal for one of the above mentioned uses.


Do they reallly make that big of a difference in handling/ride during everyday driving?

Thanks
FWIW and for less money you can get the One Up Offroad adjustable link arms. I have been told they transform the ride of our trucks incredibly.
 
#13 ·
When changing to a 4 link, the bushings in the axle are not made to be twisted like a 4 link try’s to rotate them making the bolt come loose or the travel to limited or the bushing be worn prematurely.
The steering geometry in a superduty is built around a radius arm, not a 4 link and changing to a four link will create bump steer, bump steer prematurely wears all of the suspension components including the steering box.
A 4 link will bind the drive line at full droop reducing usable wheel travel and could cause catastrophic drive line failure.
4 links are commonly sold as benefit of keeping the castor correct thru the travel, This is not a benefit that can be felt driving the truck because the radius arm does not change the castor enough until the truck is almost completely off the ground.
4 links only flex as far as the shocks travel, a radius arm will flex as far as the shocks will travel there is no difference.
The reason the sway bar is so small on a 3 link super duty is the radius arms help the sway bar make the truck feel stable in turns, changing to a 4 link and not upgrading the sway bar will increase the body roll.
Radius arms reduce body roll but still allow real world useable articulation.
When you add it all up you get all negatives and no real positives
 
#15 ·
I am not really sure how you came to those conclusions. Spending a little time on Pirate 4x4 might be a good thing for you doing some research...

The only thing on a super duty from the factory based on a radius arm setup is the size of the sway bar! The natural binding of the radius arms adds a tremendous amount of resistance just like adding a larger sway bar! Compare a Ram HD sway bar to that of a Super Duty? The Ram HD is a multi link system versus the Super Duty radius arm system!

A radius arm setup naturally binds up causing bushings to wear way faster than a 4 link setup. A 4 link setup will allow easier movement of the suspension without bind, thus not having as much bushing wear.

The bump steer relationship has little to nothing to do with the fact that the suspension uses a 4 link or a radius arm. Bump steer is determined by the track bar and drag link relationship almost exclusively!

If you are switching to a 4 link versus a radius arm, it is better that you buy a system and not just an upgrade. Many manufacturer's compensate for the great body roll with their spring and dampening rates of the shocks.

A well designed 4 link system will not bind the drive shaft much sooner than a radius arm system if the instant centers are proper. However, a 4 link system is a much more robust design than a radius arm system providing you with much more positive axle control. 4 link systems are tunable where as a radius arm system is not! You cannot alter the instant centers of a radius arm system to achieve different effects like you can a 4 link.

JP
 
#17 ·
I've had OUO's adjustable link arms since they came out (got one of the first pairs). I've also got an Icon 2.5" lift and OUO traction bars and blocks.

I'll say this, there is no body roll, no bump steer, no front wheel hop on boosted launches and this thing corners like its on rails. As for the ride, its not night and day, but you can feel the difference (the front end just behaves better).

As for which system is better, I don't know. The way it was put to me was that Ford Engineers use radius arms for a reason. OUO wanted to stay as close to factory design while also making a better product.
 
#16 ·
X2...dam can't belive the amount of misinformation in that post.

IMO get either Icon or Pure Performance's 4 link arms they will make a huge improvement in the ride quality of a '05 up suspension..we sell and install both..and use them!
 
#20 ·
The comments about the OUO parts were very complimentary. Thank you.

I don’t like to have these conflicts on forums I would rather let it be and have my post rest with what I have said. However, you insisting that I posted things that are not true and backing it up with complete bias nonsense has forced me to defend my position.

My post was not to say that OUO radius arms are not nice assemblies. I am sure they work just fine. There are just inherint differences between radius arms and a good 4 link assembly. The prior post was full of incorrect information based on geometrical facts. Not opinions.
But Facts? The good thing about the internet is you don’t have to prove anything and you don’t even need common sense, someone just says it and it is fact.

I am not really sure how you came to those conclusions. Spending a little time on Pirate 4x4 might be a good thing for you doing some research...
If that is where you all get all your suspension design information, that explains your position.

The only thing on a super duty from the factory based on a radius arm setup is the size of the sway bar! The natural binding of the radius arms adds a tremendous amount of resistance just like adding a larger sway bar! Compare a Ram HD sway bar to that of a Super Duty? The Ram HD is a multi link system versus the Super Duty radius arm system!
What does this even mean?? I think your point was agreeing with me but I can’t tell.

A radius arm setup naturally binds up causing bushings to wear way faster than a 4 link setup. A 4 link setup will allow easier movement of the suspension without bind, thus not having as much bushing wear.
On a 2005 + Superduty F250 truck, we are talking about the big rubber bushing on the axle housing. The joints that see low rotational force during cycle on a 3 link and changing it to extreme rotational force thru cycle on a 4 link. On a 3 link they see mainly linear front to back forces and a 4 link adds rotational force using up the deflection the rubber had. You say that is better, I say it is worse.

The bump steer relationship has little to nothing to do with the fact that the suspension uses a 4 link or a radius arm. Bump steer is determined by the track bar and drag link relationship almost exclusively!
If you get your suspension design from magazines and from pirates I can see how you would assume this to be true. For you to say this on public forum has lost all of your credibility on anything you say from here on out in my eyes.

If you are switching to a 4 link versus a radius arm, it is better that you buy a system and not just an upgrade. Many manufacturer's compensate for the great body roll with their spring and dampening rates of the shocks.
This is a good idea, if you going down the road of misinformation you should commit 100%

A well designed 4 link system will not bind the drive shaft much sooner than a radius arm system if the instant centers are proper. However, a 4 link system is a much more robust design than a radius arm system providing you with much more positive axle control. 4 link systems are tunable where as a radius arm system is not! You cannot alter the instant centers of a radius arm system to achieve different effects like you can a 4 link.
This one is great too.

Any one that has a dodge from 94 to 2011 knows how robust that design nightmare is. The design that made the term death wobble famous. Really seems like a huge down grade to me.

So do you sell different frame brackets to achieve different effects? Are the brackets adjustable or just the length of the arms? If you are 100% incorrect on the bump steer should we assume you have this right?

Sounds like you are just throwing out keyword terms like Miss Teen USA South Carolina?

And you can’t see on a 4 link the drive shaft’s pinion angle increases as the axle droops. If it doesn’t, how does it keep the + caster? it has to be one or the other. If I had the choice between having a drive shaft function 100% at full droop and full articulation or having good high speed drive ability at full droop or full articulation I will pick drive shaft function. It is hard to get to freeway speeds with your truck fully drooped or articulated.

We realize you and your online sales team wants to sell your systems and in your hearts you feel that you have the correct solutions to the non-problems you are fixing. You will not see my points because of your bias to your product now or ever. We would hope, for your benefit, we could just agree to disagree.
 
#21 ·
I asked Icon to reply..here it is:

When changing to a 4 link, the bushings in the axle are not made to be twisted like a 4 link try’s to rotate them making the bolt come loose or the travel to limited or the bushing be worn prematurely. - The bushing will not prematurely wear. The increase in misalignment is seen in the Rod Ends and Bearings in our 4 Link System. This is why we use these bearings and rod ends with Misalignment spacers.


The steering geometry in a superduty is built around a radius arm, not a 4 link and changing to a four link will create bump steer, bump steer prematurely wears all of the suspension components including the steering box. - Bump Steer is determined by pan rod bar angle and draglink angle. As long as these two are parallel with each other there is will be no bump steer. Changing to a 4-link system does not effect the steering angles of these two parts, therefore will not affect bump steer

A 4 link will bind the drive line at full droop reducing usable wheel travel and could cause catastrophic drive line failure. The shocks determine the amount of travel the suspension has, not the 4 link. So adding a 4 link system to a truck with the correct shocks will not cause the driveline to bind.



4 links are commonly sold as benefit of keeping the castor correct thru the travel, This is not a benefit that can be felt driving the truck because the radius arm does not change the castor enough until the truck is almost completely off the ground. This is true, but the 4 link will also help with handling. The rod ends and bearings deflect much less than the large factory bushing in the factory radius arm.

4 links only flex as far as the shocks travel, a radius arm will flex as far as the shocks will travel there is no difference.Flex (meaning Articulation) is limited by the single pivot point on the frame where the radius arm bolts to the frame. Having multiple pivot points that are allow misalign farther than the factory large bushing will increase articulation

The reason the sway bar is so small on a 3 link super duty is the radius arms help the sway bar make the truck feel stable in turns, changing to a 4 link and not upgrading the sway bar will increase the body roll. This may be true on a stock application but using the right shock and spring will improve the trucks handling.

Radius arms reduce body roll but still allow real world useable articulation. This may be true on a stock application but using the right shock and spring will improve the trucks handling.

When you add it all up you get all positives . MY words..
 
#23 ·
When changing to a 4 link, the bushings in the axle are not made to be twisted like a 4 link try’s to rotate them making the bolt come loose or the travel to limited or the bushing be worn prematurely. - The bushing will not prematurely wear. The increase in misalignment is seen in the Rod Ends and Bearings in our 4 Link System. This is why we use these bearings and rod ends with Misalignment spacers.
I am talking about the other end of the link, at the axle, the big rubber joints in the axle.

The steering geometry in a superduty is built around a radius arm, not a 4 link and changing to a four link will create bump steer, bump steer prematurely wears all of the suspension components including the steering box. - Bump Steer is determined by pan rod bar angle and draglink angle. As long as these two are parallel with each other there is will be no bump steer. Changing to a 4-link system does not effect the steering angles of these two parts, therefore will not affect bump steer
This is 100% bad information and no more than an old wives tale that keeps being repeated, and there is no truth to it. This is two dimensional thinking for a three dimensional problem. Unless bump steer and early wear is of no concern, then hey its close enough, you can just get new front end components every 20k and wonder why when you hit a bump you get feedback in the steering wheel.

A 4 link will bind the drive line at full droop reducing usable wheel travel and could cause catastrophic drive line failure. The shocks determine the amount of travel the suspension has, not the 4 link. So adding a 4 link system to a truck with the correct shocks will not cause the driveline to bind
If the 4 link rolls the pinion down as it droops out and keeps the castor positive there is no other choice but to increase the pinion angle at full droop. If the shocks or limiting straps are not just perfect the u-joint at the pinion will bind and fail, how could someone even say this is not true?

4 links are commonly sold as benefit of keeping the castor correct thru the travel, This is not a benefit that can be felt driving the truck because the radius arm does not change the castor enough until the truck is almost completely off the ground. This is true, but the 4 link will also help with handling. The rod ends and bearings deflect much less than the large factory bushing in the factory radius arm.
So we agree on something?

4 links only flex as far as the shocks travel, a radius arm will flex as far as the shocks will travel there is no difference.Flex (meaning Articulation) is limited by the single pivot point on the frame where the radius arm bolts to the frame. Having multiple pivot points that are allow misalign farther than the factory large bushing will increase articulation
So a 4 link will increase wheel travel? I thought the shocks is what limited the travel as you stated above. So which one is it?

The reason the sway bar is so small on a 3 link super duty is the radius arms help the sway bar make the truck feel stable in turns, changing to a 4 link and not upgrading the sway bar will increase the body roll. This may be true on a stock application but using the right shock and spring will improve the trucks handling.
So there are different springs and shocks for a radius arm setup and a 4 link setup?

Radius arms reduce body roll but still allow real world useable articulation. This may be true on a stock application but using the right shock and spring will improve the trucks handling.
So needing a stiffer spring to counter act for the sway bar that is now too small to control body roll equals better handling?

When you add it all up you get all positives . MY words..
Doesn’t sound positive to me.
Saying the same thing over it does not make it true. If you have 100 guys say the same thing and never prove it, still doesn’t make it true. Heck the magazines all say the same untrue things all the time. You don’t have to believe me. But if you are looking into replacing your arms, you should really thing about what adds up in your head, Fords $1,000,000 in design and engineering or the guys that think you can arbitrarily change Ford’s suspension geometry and it won’t change anything. Kind of close is close enough, right?

Not sure I know they work on a 2.5" level kit.
I know the OUO ALA’s will work on lifted, stock height and lowered trucks, They do replace the factory joint at the frame, they are fully adjustable and flex like crazy. I have them on my truck and I did not get them for free. I could have free parts from other company’s but I thought about it and these just made more sense to me.

One last thing, these statements are of my own, none of which reflects the opinion of Truck Toyz or any product company we sell.
 
#24 ·
Sak, I have a 4 link BDS lift, Am I going to have problems long term with my front end? I dont jump it or reallt offroad it. Mostly Cruizing around and road trips hauling the toys. What are my options? Stay with what I have or? I cant see that my truck rides or drives any better than any radius arm lift I have been around. Sorry for the derail but I always hear that the 4 link is the way to go. Thanks for any info.
 
#27 ·
I'm having some issues understanding how bumpsteer is determined by anything other than the drag link and track bar combination... could someone please enlighten me? If they are setup the same length and parallel to each other - then there won't be any bumpsteer present - at least that is what my experience is telling me.... can someone show me how changing from a radius arm to a 4 link and leaving all else constant has ANY effect on the bumpsteer characteristics?
 
#29 ·
I'll take the experts at Icon and Pure Performance and as you said the hundreds of others over your one voice saying that you know better than others and can see things that others can't and your product is best.. their is a term in psychology that I think would applie.
 
#32 ·
Here's a term for your a$$...CHUMP. Why don't you go peddle that Pure Performance crap somewhere else. Everybody and their brother thinks they can just buy a computer program and design a suspension system. Congrats...you've just proved that you're an idiot.

As for the best, OUO is the best jacka$$. I'll put my truck up against any other truck with that crap on it. Lets go jump #### and see which one breaks first.

I got a pretty good idea about who's gonna need a tow truck to get home.
 
#31 ·
To the OP,
Depending on the bracket of racing you are doing, it may not be allowed. Typically they are trying to prevent 4-link rearends, however it is a blanket ban for some classes. What size lift are you looking at? If it is a smaller lift height, I would consider either a 3-link or a 4-link. On larger lift sizes or long travel setups, I would only recommend a 4-link. This is just my opinion and please keep me out of the hell mess. If you need any further help Spatel, feel free to pm me.
 
#35 ·
really?


I can only assume that since your inviting me over that you think
you wanna try and kick my ass or something....


thats your answer?


I just pointed out the fact that you only had 8 posts at the
time and 6 of them were OUO related...it dont get much clearer
to see than that....

you really need to grow some thicker skin.
 
#39 ·
:whs: I 100% agree....

Now can someone help me visualize in 3D what factors have an effect on bump steer other than the drag link and the track bar?

I think very well in 3D - please explain it to me - and you don't have to dumb it down for little ole me - I'm a pretty technical guy. Explain how the bump steer is different between a properly setup radius arm suspension and a properly setup 4 link suspension that has the same operating parameters and identical track bars and drag links. Real world examples with pictures would be fantastic.
 
#41 ·
Here are some different 4-link choices. From past experience polyurethane bushings do not seem to hold up too well on heavy duty trucks. I am not pushing any certain brand. Just trying to show the differences.

Rize(Both upper and lower bars are adjustable. Also has alignment cams on lower link bars). Old style bars are different than the newly designed ones.


Icon/dr(only the bottom link bar is adjustable)




BDS(uses poly bushing and bars do not adjust)



PMF 4-link(Both arms are adjustable)



Fabtech(non adjustable 4-link bars)They do have an adjustable alignment cam on the bottom link bar.



One Up Offroad(adjustable and large heims)



Pure Performance(poly bushings) Adjustable upper and lower bars.



I am sure I am forgetting a few. Superlift and skyjacker probably don't need to be mentioned.
 
#43 ·
As a side note i have a set of BDS 4 link brackets, i should bolt them on and see if i can make a 4 link set up based off that for a stock height or lower truck.

Thats the biggest issue with 4 link set ups, is they are not available for sled pullers who are running stock front springs or lower.
 
#47 ·
Guys,

I do not want to participate in a vendor vs. vendor battle but I do wish to clarify a point.

The critical factor being overlooked by some in this discussion is axle path. Everyone seems to be more or less on the same page in regard to the importance of the relationship between the drag link and track bar in terms of vertical and horizontal moments. What is being ignored is the equally important longitudinal moment. The ability to keep the deflection rates of the drag link and track bar consistent though the fore and aft arc exhibited during the suspension cycle is every bit as important as the lateral deflection. When the axle path is changed the deflection rates of the track bar and drag link are changed as well. This relationship is complicated by the fact that the drag link and track bar are neither equal in length nor in lateral angle relative to the axle. The axle path is dictated by the geometry of the locating components (i.e. radius arms or 4-link bars). The complexity of engineering an axle path which maintains proper geometry simply cannot be done in 2 dimensions and requires 3 dimensional CAD modeling (not to mention awareness of the critical factors). Dave Hoppert of One Up Offroad and Dylan Evans of Icon Vehicle Dynamics have both spent a great deal of time refining their designs in a 3D environment.



To make a general proclamation that a 4-Link is better is like saying everything tastes better with ketchup on it without consideration for the brand of ketchup or what you are putting it on.

In regard to the assertion that a 4-link is more robust, note that many 4-link “upgrades” on the market rely on auxiliary brackets which slip into the stock radius arm mounts. When unsupported these designs apply additional leverage to the stock mount which can result in failure of the mounting rivets. This is not what I would consider a robust design.

 
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