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JKS flex link real world test.

36K views 149 replies 35 participants last post by  squinko 
#1 · (Edited)
Let me start out by saying I have had good experience with JKS in the past and have used their adj. discos and adj links in the past and still use the adj links on the rear of my rubicon.
When I saw the flex links it looked like a great idea and even tho I was put off by the $299 price tag I ended up succumbing to my impulses, which is rare for me to buy on impulse.

So yesterday I went wheeling for the day and put the flex links to the test. I went on a trail that some of you know but most won't, it is the Fisher lake trail in Montana near Phillipsburg. It is a day long trail that has a little of everything but mostly just long rough sections that if you want you can take at speed.

I intentionally did not engage my elect disconnects so the flex joints could get a work out.



there is lots of this type of terrain and I really did drive it fast to see how well the flex joints reacted. Here is the results.




as you can see in the stock form that the links come they really have very little travel and unless you spend an extra $95 you will get 0 benefit in my opinion. I could tell no difference between the stock links and the flex links. I have done this trail many times including 4 times this year so I have a pretty good basis for comparison.

The links may work great with the additional springs the $95 kit provides but I am not willing to take the gamble. I know jkeeper has said his worked great so maybe the vehicle has some bearing on how they work seat of the pants. Mine is a 14 jkur with 2.5" RK lift. I did put my Toyo 35's back on so I was running a heavier tire. I also run bfg ko2 in 34's and was thinking maybe the tire/wheel combo was too light to get them to flex but that was not the case for me.

I think JKS should say that without the additional spring pack there will be no real seat of the pants difference between these and stock.
 
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#2 ·
I think there is other variables, one obviously being 2/4 door. I love the feel of the Flex links on road, thats with the OE springs (30 %)

As i mentioned before, it would be smart for JKS to at least offer a choice, that or include the road spring in with the kit.
JKS did mention a kit but i cant imagine it being much cheaper then buying it all together.
 
#3 ·
Nice write-up and many thanks! I was on the fence with these and you just saved me $300. I'm very satisfied with my ride, both on and off-road, but always looking for improvements. The one area I am trying to improve is the body roll I get and was hoping these might help.
 
#4 ·
Thanks for the write up its nice to have an offroad review on these as it was the only reason why I was considering them
 
#6 ·
This is why JKS should give you the choice. The OE springs he's using are furthest from the softer crawl springs. (30% and i believe 70%)
JADMT's gripe has more to do with the cost and the OE springs.

I dont blame him for not spending another $100 A better review would be with the softer springs off road.
 
#7 ·
Hey guys!

I'm happy to see you guys are testing this thing out! Jadmt, you're right. You won't see a ton of difference in the rocks with the OE spring. You get a little bit over an inch of shaft travel with the spring it comes with, which is 85% of the factory sway bar spring rate. You will get more total flex out of it this way because it is engaging the factory sway bar later in the suspension cycle, but it won't be a lot. Where you see the difference while using the Flex Connect is when you purchase the Performance Spring kit. The Rock springs would change your opinion.

We are working on a Master Kit, which will include everything you need to chance spring rates, it will also come with Quicker Disconnect Studs. We are experimenting with configurations, no one has ever attempted a product like this before and we are starting from scratch.

Where the Flex Connect with the OE springs shines is on the pavement and on high speed dirt and gravel roads. You should get a better ride. I have found that customers who live in places with high quality roads with potholes see less results because they just aren't engaging the Flex Connect a lot.

Speaking from experience: I live in the LA area in a Canyon. The roads are garbage, and getting anywhere requires a little bit of canyon carving. Even my wife, who doesn't care to pay attention to my ridiculous Jeep affliction commented that the Jeep seemed to be smoother , and she asked me if I had changed anything. The only thing I changed is the Flex Connect with the OE springs.
 
#11 ·
Hey guys!

I'm happy to see you guys are testing this thing out! Jadmt, you're right. You won't see a ton of difference in the rocks with the OE spring. You get a little bit over an inch of shaft travel with the spring it comes with, which is 85% of the factory sway bar spring rate. You will get more total flex out of it this way because it is engaging the factory sway bar later in the suspension cycle, but it won't be a lot. Where you see the difference while using the Flex Connect is when you purchase the Performance Spring kit. The Rock springs would change your opinion.
We are working on a Master Kit, which will include everything you need to chance spring rates, it will also come with Quicker Disconnect Studs. We are experimenting with configurations, no one has ever attempted a product like this before and we are starting from scratch.

Where the Flex Connect with the OE springs shines is on the pavement and on high speed dirt and gravel roads. You should get a better ride. I have found that customers who live in places with high quality roads with potholes see less results because they just aren't engaging the Flex Connect a lot.

Speaking from experience: I live in the LA area in a Canyon. The roads are garbage, and getting anywhere requires a little bit of canyon carving. Even my wife, who doesn't care to pay attention to my ridiculous Jeep affliction commented that the Jeep seemed to be smoother , and she asked me if I had changed anything. The only thing I changed is the Flex Connect with the OE springs.
I see zero difference. not even a little difference nada. I am reviewing honestly I have no reason not to give my honest experience. I would look less foolish if I gave a rave review after spending $300. If you read my posts you will see I rave about products that I like and am honest about products I don't.

I live in Montana where most of the roads are bad or rough gravel roads, heck even the interstate has pot holes that will eat a semi tire.. I have over 500 miles on these so far and so far (about 250 yesterday) they are not one iota better than stock sway bar links. I am somewhat crazy but not crazy enough to spend another $100 for different springs. I would be happy to send mine back to you and you could install softer springs and see if that makes a difference.

I just went and measured and the travel (compression) was 1/4" on my offroad trip. That included higher speeds on some rough stuff. based on your 1" inch it would have to extend 3/4" of an inch and not seeing that happening as seems like force going down would be greater than pulling up on the link.

Again this is not meant as a bash as I like jks products but I think maybe it got rushed to market too soon and I ended up being a $300 beta tester. . Hopefully others will have a better experience with them or wait until jks offers them with different spring packs from the get go without having to spend $400.
 
#9 ·
I think those pre-installed springs it comes with are meant for on-road comfort. I think JKS hasn't figured out how to "package" these. If I'm correct about OE springs being mostly for on-road, based on your review I'm pretty sure they are, then JKS SHOULD include at least a set of springs for off-road.

Ever since they hit the market I've been wondering why they didn't make both links "flex-connects" instead of just one.


EDIT: My assumption was correct, jksrep just confirmed it.

TO JKSREP, if you guys do a quick disconnect type of feature for these, are you guys considering an anti-theft feature for them? I would be highly concerned.
 
#10 ·
I think those pre-installed springs it comes with are meant for on-road comfort. I think JKS hasn't figured out how to "package" these. If I'm correct about OE springs being mostly for on-road, based on your review I'm pretty sure they are, then JKS SHOULD include at least a set of springs for off-road. Ever since they hit the market I've been wondering why they didn't make both links "flex-connects" instead of just one. EDIT: My assumption was correct, jksrep just confirmed it. TO JKSREP, if you guys do a quick disconnect type of feature for these, are you guys considering an anti-theft feature for them? I would be highly concerned.
They are, and the do for my JK. JADMT did not feel a difference at all, on road or off.
 
#14 ·
For clarification on the spring rates, I've copied and pasted the description from the website, which does a pretty good job of explaining everything:

Flex Connect Kit Base Spring (Available Separately) PN PAC2110
OE Spring (Pre-installed in the Flex Connect)
- Effective spring rate is 35% softer than factory, 1.1” total link travel
- Closest spring to a stock fixed length sway bar link. Maintains road manners while still giving the benefit of absorbing the “head-bobble” type bumps
- Changes your stock sway bar system into a dual rate system.

For those looking to get the ultimate performance out of the Flex Connect link, this optional Performance Spring Kit allows for roll stiffness to be adjusted using one of the 3 unique replacement spring sets. These springs are tuned to work in different terrains or vehicle setups. The Performance Spring kit includes tools and instructions to swap out the pre-installed OE springs with any of the 3 optional spring sets. Choices can be made based on terrain or even how the Jeep is equipped for a particular trip. As the spring set rates get softer they have more travel, increasing the suspensions ability to articulate. Below, each spring spec and function is detailed. This is a guide to get started adjusting the roll stiffness of the Flex Connect system.

Performance Spring Kit Includes:

Red Spring (Road)
- Effective spring rate is 45% softer than factory, 1.3” total link travel
- High Rate/Low Travel
- For those looking to maintain on road manners but gain a little more Flex Connect travel and forgiveness over the preinstalled OE spring. Also a great choice to higher speed offroad situations

Yellow Spring (Trail)
- Effective spring rate is 60% softer than factory, 1.6” total link travel
- Mid Rate/Mid Travel
- For those looking to venture off the trail for mild offroading at moderate speeds

Blue Spring (Crawl)
- Effective spring rate is 75% softer than factory, 2.3” total link travel
- Low Rate/High Travel
- For playing in the rocks and off-camber situation. Gives more suspension articulation then a stand link/sway bar setup while maintaining the stability of the sway bar.
 
#15 ·
An edit in my previous post: I stated that with the OE spring installed you get 85% of the factory sway bar spring rate, but if you use the math skills you learned in 2nd grade, you will see what I MEANT to say was 65% of the factory sway bar rate, because 100-35=65. Hooray! The educational system in America DOES WORK!
 
#18 ·
I bought and installed last week. I have a 2015 Rubicon 4 door and was previously running the JKS quicker disconnects which I like a lot. A couple of comments:

- i think the flex connect links (only on road so far) smooth things out a bit. Not sure they are worth 300. My ride wasn't bad before but I can feel a minor improvement.
- I researched and contacted JKS before buying and I was told that they would work with the quicker disconnect pins but they do not. The pins are way too big for the flex connect. A bit disappointed as I specifically asked before ordering.
- I'm not really interested in the different springs. The price seems high and changing them out for different ride feels seems to be a rather long process of removing, taking apart, installing different spring, re-installing, etc.

The main thing I don't like is not having the quick disconnect option when I was told it would work.

Rick
 
#29 · (Edited)
I bought and installed last week. I have a 2015 Rubicon 4 door and was previously running the JKS quicker disconnects which I like a lot. A couple of comments:

- i think the flex connect links (only on road so far) smooth things out a bit. Not sure they are worth 300. My ride wasn't bad before but I can feel a minor improvement.
- I researched and contacted JKS before buying and I was told that they would work with the quicker disconnect pins but they do not. The pins are way too big for the flex connect. A bit disappointed as I specifically asked before ordering.
- I'm not really interested in the different springs. The price seems high and changing them out for different ride feels seems to be a rather long process of removing, taking apart, installing different spring, re-installing, etc.

The main thing I don't like is not having the quick disconnect option when I was told it would work.

Rick

Hey Rick,

The new 1/2" Quicker Disconnect studs/pins should work with the Flex Connect, they are what will be included in the new Master Pack once released. I can get you part numbers which you will be able to order directly from the Replacement Part section of the website.
 
#30 · (Edited)
Ok a little update. Again my build is a 14 jkur with 2.5" RK lift with Rancho 5000's shocks so it is a smooth riding jeep from the get go. I swap back and forth between Toyo 35x12.5-17 AT2 tires and BFG ko2 34x10.5-17 so on any given day I might be running E rated toyos or D rated BFG's..(I have found tires have no bearing on how mine rides with or without the flex links)

I have had the chance to put a few miles on the flex links and have over 500 miles on the links using the red springs and found them to be very similar to the stock springs which feel no different then stock swaybar links seat of the pants. No better no worse. I took a 450 mile road trip on Monday this week which included 75-80mph twisty roads and I have done this same trip many times including several this year so I have a good basis for comparison and I would bet money that nobody could tell the difference on this trip between stock links, stock flex links and flex links with the red springs.

Ok now for better news. I have now installed the yellow springs and bingo this is the springs that JKS should be including with the links. Immediate seat of the pants difference. All good no negative. I have a set of S curves that I drive every day and max speed is 30-35mph max (even guys with sport cars slow way down and with the yellow springs handled beautifully just like stock links no undue unsettled feeling at all.

I also have a dirt road close by that looks like a mine field test site and with stock links as well as with the flex links running stock springs and the red springs you had to slow down because it was such a jarring ride it would knock your fillings out. If you run dirt roads that turn to washboard roads this is what it is only there are pot holes every where too.

It is the perfect test road to see if your shocks will fade and how well the flex link works. I hit the road with the yellow springs and was amazed at how much faster I could drive and be in control and not get beat to death or have my rig want to bounce off the road. The links with the yellow springs installed totally took the edge off. Kind of feels like a well set up IFS. What makes me even more impressed I actually had my tires pumped to 36psi and I normally run 26-28psi.

Had the links came with the yellow springs I would have been happy from the get go. I have not found any negative on using the yellow springs and really think they should be standard. I have done some intentional evasive action driving to see if the jeep would react safely and it felt very settled. I have done the same think disconnected and had much less control. The yellow springs in the flex links seem to handle this type of driving much the same as being fully connected with stock links again no negatives and only positives from using the Yellow springs.

I will put some more miles on and then install the softest blue springs and see how they feel but for the time being I am very happy with the yellow springs.

It is about a 10 minute job to swap springs and no technical skill is required. If you can unscrew a bottle cap you can swap springs. I know somewhere it was mentioned that the springs would be the only wear item but after seeing the springs I believe they are lifetime springs I doubt they will wear out. They look like race car valve springs. I had a set of the jks adjustable disco links which have the same bushings and my buddy is running them now and they have around 60,000 miles and the bushings are still going strong so the bushings will last a long time too.

One other thing they quick disconnect set up works very well and works exactly like jks quick disconnect links work. You of course only have to do one side on these tho instead of both. I think with the quick disconnect set up you could literally do a spring swap in under 3 minutes if you wanted to.

When I get a chance to do some hardcore offroading (planning on Moab in Jan or feb) I will put in the blue springs and give a full eval on those but again I will say the Yellow springs feel pretty nice.

 
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#32 ·
I absolutely knew you were going to ask that lol.
Over double what the stock ones did and this was not on nearly as rough of a ride. I can say the reds or stock would not have moved an 1/8" on what moved the yellows over 1/2". The yellow springs traveled more just on the pavement dips than the stock ones did on the off road trip.
 
#34 ·
I have to agree the stock ones are so close to useless they should of not bothered with them . Yellow would of been a better choice installed initially I feel. The stock silvers could of remained as some ones valve springs . For me yellow is fine on the street. It may be some what because my shocks have always seemed a bit stiffer than I liked. Now they have a little more working against them so it seems softer on the road with no big difference in body roll. That also may be due to the height of the AEV rear track bar mount that increased the roll center more than some for the lift height . I still think I can possibly do a little work to soften up the rear sway bar some more also. I will experiment with that after this damn storm passes.
 
#36 ·
I am used to a soft setup maybe a little more body roll than some. I'm used to my TJs that I have always had antirocks on . The 05 short arms with Bilstein 5100s and the 99 with Clayton long arms and Rancho 9000XLs . I just feel like the yellow springs got me closer to that ride in the front. This JK with the AEV suspension just stays so flat cornering I figure I can do a few things to soften it up and still handle decent . I am trying to work with what I have to justify what I have bought so far without dumping the 5100s for the 9000XLs. Not that I have been over joyed with them either.
 
#38 ·
Reading this thread I think the reason the units are shipped with such stiff springs is a liability issue. The sway bar is a major component responsible for handling and control. If they were shipped with the softest springs and someone loses control and crashes as a result, the liability is with the manufacturer unless it is specifically stated as off road use only. If you chose to open the units yourself and fit softer springs, the liability would be on the owner I would imagine? Their web page starts of by saying the OEM springs will retain road handling but once you read about the softer springs they only discuss off road driving.
 
#40 ·
I need to update this thread. I did suffer a link failure while in Moab. I would caution that if you have an electronic sway bar discos and have a suspension system that has considerable droop i.e. Long shocks and coils you might want to manually disco when off road. If you electronically disco and max flex its possible for the link to fail due to the bushing popping out of the housing. There is termendous force on the joint when the axle droops and shifts. Jks replaced the damaged flex link.
 
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#43 ·
This is a point I want to be clear about. I have a Metalcloak 3.5 on a Rubi. Your saying it's better to manually disconnect on tough trails? I am doing a jeep jamboree next week and doing some tougher trails. Will you get more flex by doing this or is it just easier on the parts?
 
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#42 ·
No that was legit. If I would have not been electronically disconnected there would not have been an issue. I can tell you I'm spoiled by it. I have long shocks and rk coils have long Fred length so when elec discod there is a lot of side force on the link.
 
#44 ·
Yes remove the flex link completely via quick disconnect mounts. If you just disco by pushing the button and leave the link in place you risk ruining the link. Id post a photo but can not figure out my iPad and I'm computerless St the time
 
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#45 ·
 
#47 ·
 
#48 ·
So I am guessing you guys only use this for the street and fire roads/ light trails? Then disconnect when on the harder stuff?

I am wondering if it would be worth it for me. My Billsteins are a little stiff and on concrete slab highway theres a lot of the bounce back and forth. Was looking into quicker disconnects and this looks like it could improve my ride a little too?
 
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