Look at that droop! Rock Krawler 4-Link Rear Conversion

[5GENIDN]

I'm gonna be that guy and ask, what's the benefits of a 4 link vs whatever we got now? Suspension is Spanish to me, Audio and electronics are Chinese

You know how the Rock jock relocation bracket helped with bump steer? The 4 link completely eliminates any bump steer at all by eliminating the track bar all together....

Now the big thing with the 4 link is that it is suppose to allow for more articulation of the rear axle. I get how it does that over stock... The stock arms have polymer bushings that work like a second set of springs resisting axle articulation. This replaces the polymer joints with joints that will not restrict any movement... So now the only thing that will limit any articulation of that rear axle is the coil overs. The axle can now move as far as they can move. BUT Mine can do the same... I changed out all 5 of my arms to arms with johnny joints..... They move freely. The only thing restricting my rear axle articulation is the coil overs.... My movement should be the same....

Now I would love to completely eliminate the bump steer. Mine is not that bad because I have minimized it... My track bar is flat.... (the more angle to your track bar the more bump steer.)...

I am not completely sold on the long term durability of the new frame mounts for the upper arms. There are a lot of 4 links out in the wild especially in jeep world... I just know physics and the lateral loading on a leveraged arm is significant. Very significant. I know they hold up for a long time in the examples that are in use..... BUT how long? This is a new design for the Bronco... I think it is a good design... But for me cost vs benefit.... I am not quite there yet... I am sure these guys are going to prove all of my doubts/questions wrong....

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[SierraBronco]

You know how the Rock jock relocation bracket helped with bump steer? The 4 link completely eliminates any bump steer at all by eliminating the track bar all together....

Now the big thing with the 4 link is that it is suppose to allow for more articulation of the rear axle. I get how it does that over stock... The stock arms have polymer bushings that work like a second set of springs resisting axle articulation. This replaces the polymer joints with joints that will not restrict any movement... So now the only thing that will limit any articulation of that rear axle is the coil overs. The axle can now move as far as they can move. BUT Mine can do the same... I changed out all 5 of my arms to arms with johnny joints..... They move freely. The only thing restricting my rear axle articulation is the coil overs.... My movement should be the same....

Now I would love to completely eliminate the bump steer. Mine is not that bad because I have minimized it... My track bar is flat.... (the more angle to your track bar the more bump steer.)...

I am not completely sold on the long term durability of the new frame mounts for the upper arms. There are a lot of 4 links out in the wild especially in jeep world... I just know physics and the lateral loading on a leveraged arm is significant. Very significant. I know they hold up for a long time in the examples that are in use..... BUT how long? This is a new design for the Bronco... I think it is a good design... But for me cost vs benefit.... I am not quite there yet... I am sure these guys are going to prove all of my doubts/questions wrong....

I’m hoping the crazy misalignment abilities that the PB&J lower links provide help with the stresses that will be placed on the frame mounts. It’s awesome how much flex ours now has but with awesome street manners.

 

[5GENIDN]

I’m hoping the crazy misalignment abilities that the PB&J lower links provide help with the stresses that will be placed on the frame mounts. It’s awesome how much flex ours now has but with awesome street manners.

The street manners and articulation are EXACTLY what I would expect with that design... The flexibility in the joints will not alleviate any pressures on those mounts though.... I am sure it will hold up, these guys have designed built and tested thousands of these over the years.... I guess it is the structural overbuild side of me that is just having a hard time with that leverage....

 

[SierraBronco]

The street manners and articulation are EXACTLY what I would expect with that design... The flexibility in the joints will not alleviate any pressures on those mounts though.... I am sure it will hold up, these guys have designed built and tested thousands of these over the years.... I guess it is the structural overbuild side of me that is just having a hard time with that leverage....

**starts shopping for suitcase welders**

 

[5GENIDN]

**starts shopping for suitcase welders**

No NO NO.... This is inspect after hard trail runs and watch for fatigue and cracking type concerns in my mind....

and if something were to appear it probably would not appear for several years of hard use...

 

[SierraBronco]

No NO NO.... This is inspect after hard trail runs and watch for fatigue and cracking type concerns in my mind....

“I suddenly have way more droop and much less control. Maybe I will look at those mounts I’ve been ignoring”

 

[CarmeloS]

You know how the Rock jock relocation bracket helped with bump steer? The 4 link completely eliminates any bump steer at all by eliminating the track bar all together....

Now the big thing with the 4 link is that it is suppose to allow for more articulation of the rear axle. I get how it does that over stock... The stock arms have polymer bushings that work like a second set of springs resisting axle articulation. This replaces the polymer joints with joints that will not restrict any movement... So now the only thing that will limit any articulation of that rear axle is the coil overs. The axle can now move as far as they can move. BUT Mine can do the same... I changed out all 5 of my arms to arms with johnny joints..... They move freely. The only thing restricting my rear axle articulation is the coil overs.... My movement should be the same....

Now I would love to completely eliminate the bump steer. Mine is not that bad because I have minimized it... My track bar is flat.... (the more angle to your track bar the more bump steer.)...

I am not completely sold on the long term durability of the new frame mounts for the upper arms. There are a lot of 4 links out in the wild especially in jeep world... I just know physics and the lateral loading on a leveraged arm is significant. Very significant. I know they hold up for a long time in the examples that are in use..... BUT how long? This is a new design for the Bronco... I think it is a good design... But for me cost vs benefit.... I am not quite there yet... I am sure these guys are going to prove all of my doubts/questions wrong....

The stock setup is a 4link as well, this one incorporates triangulation through the upper trailing arms curving inward. This keeps the axles centered under the truck. The factory setup accomplishes this by the use of a Panhard/track bar, but that binds up the rear suspension. With the factory setup, you may notice a weird shift when hitting a break in the pavement or railroad tracks. That doesn’t happen with this kit. By using the Rock Krawler triangulation kit, the benefits include smoother ride/handling and better articulation (claims of 30% more). Our friends Adventures of Rogers and Henderson explain this very well in their video. @EvanPeterson

Okay, makes perfect sense now. Thank you guys!

 

[5GENIDN]

“I suddenly have way more droop and much less control. Maybe I will look at those mounts I’ve been ignoring”

That "droop" though is awesome.... Yes your suspension is going to be a lot more fluid.... That is because you got rid of those polymer bushings that resisted movement.... Celebrate that! Control??? Is there anything in my life that I am in control of????

My guess is that it is just a whole new freedom that you will become accustomed to.

 

[SierraBronco]

That "droop" though is awesome.... Yes your suspension is going to be a lot more fluid.... That is because you got rid of those polymer bushings that resisted movement.... Celebrate that! Control??? Is there anything in my life that I am in control of????

My guess is that it is just a whole new freedom that you will become accustomed to.

Broken suspension mounts for the win!

 

[5GENIDN]

Broken suspension mounts for the win!

NO......

I still have pictures in my head of the early Broncos (2021s) that had fatigue cracking on their upper control arm mounts discovered here more recently.... and then a realization that Ford had redesigned that mount somewhere in late 2021 without telling anyone. Guys just welded them up and added some additional bracing... all good I think.

 

[Arokcrwlr]

You know how the Rock jock relocation bracket helped with bump steer? The 4 link completely eliminates any bump steer at all by eliminating the track bar all together....

Now the big thing with the 4 5 link is that it is suppose to allow for more articulation of the rear axle. I get how it does that over stock... The stock arms have polymer bushings that work like a second set of springs resisting axle articulation. This replaces the polymer joints with joints that will not restrict any movement... So now the only thing that will limit any articulation of that rear axle is the coil overs. The axle can now move as far as they can move. BUT Mine can do the same... I changed out all 5 of my arms to arms with johnny joints..... They move freely. The only thing restricting my rear axle articulation is the coil overs.... My movement should be the same....

Now I would love to completely eliminate the bump steer. Mine is not that bad because I have minimized it... My track bar is flat.... (the more angle to your track bar the more bump steer.)...

I am not completely sold on the long term durability of the new frame mounts for the upper arms. There are a lot of 4 links out in the wild especially in jeep world... I just know physics and the lateral loading on a leveraged arm is significant. Very significant. I know they hold up for a long time in the examples that are in use..... BUT how long? This is a new design for the Bronco... I think it is a good design... But for me cost vs benefit.... I am not quite there yet... I am sure these guys are going to prove all of my doubts/questions wrong....

In theory, the triangulated 4 link should have greater articulation than the factory 5 link even with Johnny joints. The coilovers may be the limiter either way, but if you remove the coilovers, the factory orientation of the upper arms should bind before the triangulated arms will. I already had RockJock arms with Johnny joints and still lifted a tire when I thought I shouldn't have. We'll see if this new 4 link will be an improvement...

 

[SierraBronco]

NO......

I still have pictures in my head of the early Broncos (2021s) that had fatigue cracking on their upper control arm mounts discovered here more recently.... and then a realization the Ford had redesigned that mount somewhere in late 2021 without telling anyone. Guys just welded them up and added some additional bracing... all good I think.

Lmao. I mean, it’s funny to think about. Ford recognizes there’s a problem and doesn’t say anything to current owners. Just makes a lil change in secrecy and hopes nobody notices.

 

[5GENIDN]

In theory, the triangulated 4 link should have greater articulation than the factory 4 link even with Johnny joints. The coilovers may be the limiter either way, but if you remove the coilovers, the factory orientation of the upper arms should bind before the triangulated arms will. I already had RockJock arms with Johnny joints and still lifted a tire when I thought I shouldn't have. We'll see if this new 4 link will be an improvement...

I agree with you... BUT additional articulation does you no good if it is limited by something else....

I disagree that the upper arms would would bind on a 5 link with Johnnies.... The problem with a 5 link is that all of the movement has to cycle along an arc.... So yes if that arc movement angled the upper into the mount or some other part... Yea... But again It can not go that far (at least if the track bar is in the neutral position- Horizontal).... I am limited by the coil over movement... Just like a 4 link. I do not like being on that arc.... 4 link solves that... They have immense benefits but I am sure the "additional articulation" is measured against the stock polymer bushings... Those polymer bushings do NOT like to articulate.

 

[RP80]

Sweet! Just had mine done as well. Will be wheeling through rough New England rocks on Friday so will report back. For now, the on-road handling improvement is truly amazing. Worth the price for this alone.

We also welded the diff tube for extra insurance to those fussy plug welds.

 

[5GENIDN]

In theory, the triangulated 4 link should have greater articulation than the factory 4 link even with Johnny joints. The coilovers may be the limiter either way, but if you remove the coilovers, the factory orientation of the upper arms should bind before the triangulated arms will. I already had RockJock arms with Johnny joints and still lifted a tire when I thought I shouldn't have. We'll see if this new 4 link will be an improvement...

Did you have all 5 arms changed to Johnnies???? I am curious because that would suggest something else was limiting.... I am just not sure what that could be... I will be the first to admit that the theory of the 4 link is far superior to the 5 link.... My one and only concern is the lateral loading that in all probability will pan out to be a non-issue.

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