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Discussion Starter #1
You see it posted almost everyday “new jeep owner, what lift?” and we go thru the motions of what are you going to do with it and what tire size. You also get endless posts of “I am running ***** lift and it is better then stock” along with a poser shot. I still to this day do not understand how someone can see the suspension on a rig from 25 feet away in a photo. Those two important questions to consider when doing a lift, tire size and what you plan to do with it are the keys to setting up your suspension. I am keeping these thoughts mainly on the bolt on kits for the JK.

Most of the op’s have the misconception that somehow a bolt on lift will give them more articulation or “flex” and that a lift will make the Jeep more capable off road. Most will not and some will even make them less capable in some areas when compared to the factory suspension. Reduced wheel base, coil unloading, and low roll center are just some of the things that can happen with an incomplete bolt on kit that will be detrimental to off road performance. Play around with a 4 link calculator if you want to see how much your lift is messing with the actual geometry of your Jeep. The higher you go the worse it gets too.

While a 4” lift will increase the amount of up travel you have if you don’t run a longer shock you will loose 4” of down travel for a net increase in flex of zero. Add a 2” bump stop to the above example and you just lost 2” of flex vs the factory suspension set up. I think most people have this misconception of increased flex due to the fact they usually add larger tires when they lift and that is where they are seeing the improvement off road.

Many manufactures will use names with the word flex in them to describe their arms, lift kits, or joints. These are just marketing terms and do not flex any more then another bolt on kit from other manufacturers. The “upgradeable lift” is another myth made up from the marketing team. Any lift out there is upgradeable, there is nothing special about one that advertises it as one. The term "mid arm" is also a term that is made up by a marketing team, in reality it is the same basic length as the factory arm. They use this term in comparison to the tj control arms that were really short.

I believe that a lift is needed to gain clearance for increased tire size. It can also be used to gain some belly clearance for break over angle (mainly on the 4 door) and for better approach and declination angles, although I would argue that tires should be used for these issues instead of just lifting. The bigger your tires the more total ground clearance you will have as well as improving your break over, approach, and declination angles. I understand that other factors will come into play with large tires, mainly gears, wheel bs, and fuel economy.

If you were to compare two Jeeps, one set up with a 4" short arm kit on 33" tires and one with a 2" lift and 37" tires with trimmed fenders the one on 37's, if properly geared, would run circles around the higher lifted Jeep. It would climb better, clear bigger rocks, be more stable in off camber situations, and would handle better on road due to the lower center of gravity. Both Jeeps would be the same height overall.

For me the thoughts on lifts would be to start with trimmed or flat fenders for 33’s add a 2” lift for 35’s a 3” lift for 37’s 4” for 40’s
Expect some trimming of pinch seams as your tires get larger in size.

Wheel bs should be included in the discussion as well to maintain full steering. Wheel back spacing for the previous lift recommendations on factory width axles.

Net max back spacing:
5.5” for a 33x12.5
4.5” for 35x12.5
3.5” for 37x12.5
1.75” for a 40x13.5



The Parts:

Coils:

Coils are what gives your Jeep it’s ride height, in its most simple form a lift is just longer coils or a spacer placed on top of the coils. The benefit of a longer coil vs a spacer lift is that it will have a bit more travel built into it so you can droop a bit more and run a longer travel shock. A dual rate coil is made with a light coil rate section that will compress at ride height and allow for an even longer throw at full extension allowing for the potential of increased articulation. A coil that minimizes lift and maximizes unloaded length will give you the most benefit for increasing flex and off road performance.
One drawback from a coil that is really long is unloading that occurs on a steep climb or decline when the coils push the jeep away from the axles and give you the possibility of flopping onto the roof. Limit straps and suck down winches can help with that problem. ORI struts have a built in feature that eliminate this problem as well.

Shocks:

Shocks control the compression and rebound of the coils, quality of the ride, and the upper and lower limit to a suspension. To increase articulation, total travel is what you are looking for. Typically for 33”-35” tires you will be looking at a 10” travel shock. With 37”-40” a 12” travel shock will do. These are for bolt on kits, if you want to get adventurous and are willing to cut and weld 14”-16” are doable with considerable effort.

When running a longer travel shock you will have to take into account the rotation of the axle when one wheel is drooped and one is stuffed. The stuffed wheel will travel farther into the wheel well and you will experience more axle shift where a driveshaft may make contact with the fuel tank or oil pan.



Bump Stops:

Bump stops are there to keep your tires and other suspension components from rubbing on fenders and the frame. They are also used to keep shocks from totally compressing which can potentially damage them. When adding larger tires or doing a drag link flip you will need to add bump stops to keep things from rubbing. You can also trim fenders or notch the frame to gain extra up travel. Remember when adding bump stops you are limiting your up travel and are reducing your flex. Trimming fenders or running flat fenders is a good way to increase flex if tire rubbing the fenders is your limiting factor vs running longer bump stops.

Limit Straps:

Limit straps limit your down travel and can reduce your flex. However If set up properly the limit strap will prevent your shocks from totally extending, potentially damaging them, and can actually allow you to increase flex by overcoming the limitations of other components such as the drive shafts. By placing a limit strap at the differential you can limit the angle of the u joints or keep a driveshaft from making contact with the exhaust cross pipe while still allowing more droop at the wheels so the axle can rotate over obstacles. I have not seen a single lift that offers limiting straps, though they should be in every kit over 3” at least at the front driveshaft.

Sway bars and links:

While most of you disconnect your sway bars when off roading, (I don’t run them at all but my set up is far from a bolt on) should you run off road with them connected you run the risk of flipping your sway bar forward if your sway bar links are too short. This will lock up your steering and will likely bend stuff. They should be sized so they are +- 5 degrees from level. I would error at the +5 if it were me as I have flipped mine a couple of times when I over extended the front end.

Disconnecting the links will give you more potential travel in your suspension but will also make it less stable in off camber situations. After market sway bars like the TeraFlex duel rate or the Currie anti-rock will give you extra stability while having a softer twist rate for articulation.

Track Bars:

Track bars keep your axles centered on the Jeep. As you articulate your suspension the axle will shift from side to side. When you droop the front the axle moves to the driver side. The opposite happens on the rear. As you lift the track bar becomes more angled and due to that angle will shift more then a stock or level track bar. The track bar also determines your roll center. This is a line drawn thru the center of the front and rear track bars to determine how the vehicle will roll on its suspension from side to side. Think of a top heavy feeling from a low roll center. Raising the rear axle side track bar bracket will increase the roll center and make the Jeep feel more stable during off camber situations and on road cornering. The front track bar needs to stay parallel to the drag link for proper steering geometry and only should be raised when in combination of a drag link flip (done typically at 3.5”+ of lift). Many bolt on lift companies will give you an adjustable front track bar to re-center your axle and a raised rear axle side bracket that raises the track bar mount by the same amount as the lift which will center the axle with the factory track bar. Some of the manufacturers that make lower end kits will address the track bar issue by including a frame side lowering bracket as well as a drop pitman arm. While this will correct the steering geometry, it will lower the roll center of the Jeep making it less stable in cornering on road and more tippy in off camber situations. The drop pitman arm will also increase the stress load on the steering box and can lead to bent sector shafts as well as leaking seals on the steering box.
 

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Discussion Starter #2
Fixed Length Control Arms:

These are offered on some lower priced kits to keep the cost down while correcting suspension geometry (mainly caster) for the amount of lift in the kit. They typically use the same low priced clevite joint that the factory arms use.

Rod End Joints:

End joints are used to help comfort the ride from vibration and give it some flex in the connection point to allow for articulation. The more the misalignment built in the joint the more flex you can do without putting stress on the control arm mounts. Will some joints allow for more articulation then others? The answer is yes in theory but when installed on the JK factory brackets all aftermarket joints will perform about the same due to other constraints on the JK that limit articulation. This is one of the areas of a lift kit that can really bump up the cost. If a lift manufacture used 16 Johnny joints vs the factory style clevit joint the cost difference would be in the $500 range. A double adjuster on a control arm will increase the costs roughly $35 per arm.

Steering:

Steering linkages is another discussion for another day but will play a part in lifts 2.5” and taller.

Just for disclosure, I have never actually purchased a "lift kit" although I have installed them on others rigs.

These are just my thoughts on lifts after years of messing around with TJ’s and JK’s other people may have different thoughts and experiences and feel free to jump in the discussion. I would prefer the discussion to concentrate on bolt on kits for the JK and not suspension theory of rock bouncers and koth rigs.

 

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You see it posted almost everyday “new jeep owner, what lift?” and we go thru the motions of what are you going to do with it and what tire size. You also get endless posts of “I am running ***** lift and it is better then stock” along with a poser shot. I still to this day do not understand how someone can see the suspension on a rig from 25 feet away in a photo. Those two important questions to consider when doing a lift, tire size and what you plan to do with it are the keys to setting up your suspension. I am keeping these thoughts mainly on the bolt on kits for the JK.



Most of the op’s have the misconception that somehow a bolt on lift will give them more articulation or “flex” and that a lift will make the Jeep more capable off road. Most will not and some will even make them less capable in some areas when compared to the factory suspension. Reduced wheel base, coil unloading, and low roll center are just some of the things that can happen with an incomplete bolt on kit that will be detrimental to off road performance. Play around with a 4 link calculator if you want to see how much your lift is messing with the actual geometry of your Jeep. The higher you go the worse it gets too.



While a 4” lift will increase the amount of up travel you have if you don’t run a longer shock you will loose 4” of down travel for a net increase in flex of zero. Add a 2” bump stop to the above example and you just lost 2” of flex vs the factory suspension set up. I think most people have this misconception of increased flex due to the fact they usually add larger tires when they lift and that is where they are seeing the improvement off road.



Many manufactures will use names with the word flex in them to describe their arms, lift kits, or joints. These are just marketing terms and do not flex any more then another bolt on kit from other manufacturers. The “upgradeable lift” is another myth made up from the marketing team. Any lift out there is upgradeable, there is nothing special about one that advertises it as one. The term "mid arm" is also a term that is made up by a marketing team, in reality it is the same basic length as the factory arm. They use this term in comparison to the tj control arms that were really short.



I believe that a lift is needed to gain clearance for increased tire size. It can also be used to gain some belly clearance for break over angle (mainly on the 4 door) and for better approach and declination angles, although I would argue that tires should be used for these issues instead of just lifting. The bigger your tires the more total ground clearance you will have as well as improving your break over, approach, and declination angles. I understand that other factors will come into play with large tires, mainly gears, wheel bs, and fuel economy.



If you were to compare two Jeeps, one set up with a 4" short arm kit on 33" tires and one with a 2" lift and 37" tires with trimmed fenders the one on 37's, if properly geared, would run circles around the higher lifted Jeep. It would climb better, clear bigger rocks, be more stable in off camber situations, and would handle better on road due to the lower center of gravity. Both Jeeps would be the same height overall.



For me the thoughts on lifts would be to start with trimmed or flat fenders for 33’s add a 2” lift for 35’s a 3” lift for 37’s 4” for 40’s

Expect some trimming of pinch seams as your tires get larger in size.



Wheel bs should be included in the discussion as well to maintain full steering. Wheel back spacing for the previous lift recommendations on factory width axles.



Net max back spacing:

5.5” for a 33x12.5

4.5” for 35x12.5

3.5” for 37x12.5

1.75” for a 40x13.5







The Parts:



Coils:



Coils are what gives your Jeep it’s ride height, in its most simple form a lift is just longer coils or a spacer placed on top of the coils. The benefit of a longer coil vs a spacer lift is that it will have a bit more travel built into it so you can droop a bit more and run a longer travel shock. A dual rate coil is made with a light coil rate section that will compress at ride height and allow for an even longer throw at full extension allowing for the potential of increased articulation. A coil that minimizes lift and maximizes unloaded length will give you the most benefit for increasing flex and off road performance.

One drawback from a coil that is really long is unloading that occurs on a steep climb or decline when the coils push the jeep away from the axles and give you the possibility of flopping onto the roof. Limit straps and suck down winches can help with that problem. ORI struts have a built in feature that eliminate this problem as well.



Shocks:



Shocks control the compression and rebound of the coils, quality of the ride, and the upper and lower limit to a suspension. To increase articulation, total travel is what you are looking for. Typically for 33”-35” tires you will be looking at a 10” travel shock. With 37”-40” a 12” travel shock will do. These are for bolt on kits, if you want to get adventurous and are willing to cut and weld 14”-16” are doable with considerable effort.



When running a longer travel shock you will have to take into account the rotation of the axle when one wheel is drooped and one is stuffed. The stuffed wheel will travel farther into the wheel well and you will experience more axle shift where a driveshaft may make contact with the fuel tank or oil pan.







Bump Stops:



Bump stops are there to keep your tires and other suspension components from rubbing on fenders and the frame. They are also used to keep shocks from totally compressing which can potentially damage them. When adding larger tires or doing a drag link flip you will need to add bump stops to keep things from rubbing. You can also trim fenders or notch the frame to gain extra up travel. Remember when adding bump stops you are limiting your up travel and are reducing your flex. Trimming fenders or running flat fenders is a good way to increase flex if tire rubbing the fenders is your limiting factor vs running longer bump stops.



Limit Straps:



Limit straps limit your down travel and can reduce your flex. However If set up properly the limit strap will prevent your shocks from totally extending, potentially damaging them, and can actually allow you to increase flex by overcoming the limitations of other components such as the drive shafts. By placing a limit strap at the differential you can limit the angle of the u joints or keep a driveshaft from making contact with the exhaust cross pipe while still allowing more droop at the wheels so the axle can rotate over obstacles. I have not seen a single lift that offers limiting straps, though they should be in every kit over 3” at least at the front driveshaft.



Sway bars and links:



While most of you disconnect your sway bars when off roading, (I don’t run them at all but my set up is far from a bolt on) should you run off road with them connected you run the risk of flipping your sway bar forward if your sway bar links are too short. This will lock up your steering and will likely bend stuff. They should be sized so they are +- 5 degrees from level. I would error at the +5 if it were me as I have flipped mine a couple of times when I over extended the front end.



Disconnecting the links will give you more potential travel in your suspension but will also make it less stable in off camber situations. After market sway bars like the TeraFlex duel rate or the Currie anti-rock will give you extra stability while having a softer twist rate for articulation.



Track Bars:



Track bars keep your axles centered on the Jeep. As you articulate your suspension the axle will shift from side to side. When you droop the front the axle moves to the driver side. The opposite happens on the rear. As you lift the track bar becomes more angled and due to that angle will shift more then a stock or level track bar. The track bar also determines your roll center. This is a line drawn thru the center of the front and rear track bars to determine how the vehicle will roll on its suspension from side to side. Think of a top heavy feeling from a low roll center. Raising the rear axle side track bar bracket will increase the roll center and make the Jeep feel more stable during off camber situations and on road cornering. The front track bar needs to stay parallel to the drag link for proper steering geometry and only should be raised when in combination of a drag link flip (done typically at 3.5”+ of lift). Many bolt on lift companies will give you an adjustable front track bar to re-center your axle and a raised rear axle side bracket that raises the track bar mount by the same amount as the lift which will center the axle with the factory track bar. Some of the manufacturers that make lower end kits will address the track bar issue by including a frame side lowering bracket as well as a drop pitman arm. While this will correct the steering geometry, it will lower the roll center of the Jeep making it less stable in cornering on road and more tippy in off camber situations. The drop pitman arm will also increase the stress load on the steering box and can lead to bent sector shafts as well as leaking seals on the steering box.
Great write up

Sent from my SM-N950U using Tapatalk
 

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When I have some time I will read through your post and if you want I can PM you some of my thoughts.
I have lifted a few jks and have made list for people looking to buy lifts/tires.
My jeep is pretty much all "custom". my lift uses heims, dom and ruff stuff brackets.

Sent from my SM-G935V using Tapatalk
 

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Thank you for taking the time to write that up. Helped me to understand some issues I'm having with my lift...
 

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First you have to start talking about guitars to get his attention.

I think Jeffery should be a mod.:thankyou:

My bad forgot about that let's see here.


My younger than me wife and my dead rat just bought me the best old school Gibson guitar, but I don't play them so if only I knew of someone who plays and loves guitars that I could give this to...… any thoughts @StubEXrube oh and while you're here maybe sticky...or not :x
 

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First you have to start talking about guitars to get his attention.

I think Jeffery should be a mod.:thankyou:




I'd be honored plus gentle and fair...

:thefinger:


Just scream ,
" @StubEXrube !!
Free lubrication !
Free Dean Markley strings!
There's a dead rodent in the cowling!!! "

that'll usually bring him around ....
 

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Thank you for compiling this Dirtman. This article will be used as my 'go to' when purchasing new parts...:rockon:
 

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Thanks Dirtman! I've been eyeballing my bumpstops and wondering if they were too long. I will have to check it out when I get a chance soon.
 

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Discussion Starter #17
I ran a 3 link rear for a while and did not like it. Felt too loose in the rear. Hard to get good geometry with the frame side upper mount being so high due to the drive shaft. Requires you to run a really high bridge and then you loose available up travel. This is likely why you don't see many manufacturers offer the 3 link.
 

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I ran a 3 link rear for a while and did not like it. Felt too loose in the rear. Hard to get good geometry with the frame side upper mount being so high due to the drive shaft. Requires you to run a really high bridge and then you loose available up travel. This is likely why you don't see many manufacturers offer the 3 link.
Makes sense ,we recently had a big event in logandale . I was trying to get this guy in a JLU on tons and 40s threw a big v notch that's shaped like a z . He had a front and rear 3link . It traked like crap! I had gotten half a dozen rigs through with no problem. But the 3link sucked balls.
(So did the driver )but still the rear just didn't follow well with full flex.

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If you bring into the discussion the mechanical advantage increase for a given tire to climb an obstacle it may help those who don't understand how a 2.5" lift with flat fenders and 37's will out perform a 3.5 or 4.5" lift with stock fenders and 35's on a given vehicle.

The misconception of the bridge height of a 3 link versus a 4 link is just that. If you are putting an arm and given joint size above the differential it takes up the same spaces wether that be a 3 link or a triangulated 4 link. You can achieve your desired instant centers and roll centers with either set up. With the triangulated 4 link you will position all your control arm mounts to achieve the desired IC and RC. With the Independent 3 Link you will position the upper arm mounts and lower arm mounts to achieve the desired IC and the track bar mounts will achieve your desired RC. This just satisfies theories or packaging requirements. The "how it feels" will also be affected by spring rates, shock rate and positioning, and sway bars. All of those things need to come together wether you are doing a Independent 3 Link or Triangulated 4 Link arrangement.
 

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Discussion Starter #20
There is no misconception. On a 3 link like yours you have to build around the frame upper link which is above the driveshaft. With this being fixed it limits where you can put axle and frame lower brackets so you can increase ground clearance. If you move the lower links up for clearance then your geometry goes out the window. If I put your single upper link in where you do I would get -1% anti squat, in order to get it close to where I am at 74% anti-squat I would have to raise the axle side upper mount up around 3". To compensate for a -1 anti squat I would have to run a really high rate coil that would ride rough and would not compress very good under articulation. You could also run a high rate sway bar to help with stabilization but then again you compromise articulation.

With my set up I can run 7" of up travel and have more ground clearance with a low coil rate and a 2 door anti rock. I am 78" to the top of my windshield for reference on lift height. On road my ride is very nice and off road the suspension really soaks up bumps without the side to side jarring ride I have experienced in every jeep I have rode in with a RK 3 link. I also have better clearance under the jeep and axle and don't have the axle shift you get with running a pan hard bar. Is not the main reason to run big tires and lift to gain clearance and articulation?

Yes your 3 link allows you to run a long arm and retain the factory tank but has many compromises to do it in terms of ride quality and tracking. And again if a 3 link was so great why does not every manufacturer have one?
 
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