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My thoughts on lifts.

47157 Views 61 Replies 26 Participants Last post by  lanceberens
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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Just so you know

RE, TNT and a few others have 3 links. Why do most companies run long lowers and short uppers that don't even comply to the 80% thumb rule? That is a better question.

Harsh ride is something we never hear regarding our long arms. Ride quality can be tuned to just about any suspension geometry. We try to stick to general factual information and not opinions. We were speaking in general discussion terms. Not talking brands, not talking anything other than general terminology.

Where did you mount your upper arms for your triangulated 4 link? Shoot a pic please. That would be very helpful for all to see.

Every factor of suspension can be tuned as stated in our prior post. We run all forms of suspension geometry in many many applications! In our last race rig we actually ran a reverse triangulated 4 link in the rear on the JK-R which in my opinion is the optimum suspension geometry in the rear by far. That is just my opinion though. With that geometry you have the most amount of up travel available, but it does require a fuel cell either inside the vehicle or behind the rear axle which is illegal in all states! Federal law requires any vehicle on the road to have the fuel tank located between the axles since 2007.

X2 Geometry for the rear of the JK gets released Jan 1. This is based off our Trail Runner and Trail Demon geometry in the rear and matches what we have done in the JL.

If you are talking an off road only vehicle, sure a lot of things come into play and if you want to wheel your rig against our JK-R we are down for sure.

But if we are referencing street driven vehicles we have to ensure they are compliant with Local and Federal Laws.
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my uppers are mounted as high as they can be mounted under the tub in the corner of the frame, If it were in the same spot as your center mounted 3 link it would hit the driveshaft. Yes I rip on kits like the Teraflex long arm that uses really short uppers and has crazy pinion angle changes under articulation and I think their speed bumps are a joke and they rip people off with them. I am not a big fan of the 80% rule either, I think the upper and lower links should be closer to length then that and your goal should be to put the frame mounts as close to the output shaft as you can. I typically build with uppers being longer then lowers.

Your trail runner was the worst riding lift I have ever been in. There is a video posted and we have been thru this before, not looking to relive it. You guys blamed it on the shock oil and 32 degree weather even though the jeep was stored in a heated building before the test run.

My rig is not an off road only and runs on the road way more than off. AS far as legal, sell a lot of Illegal lifts around the country that cause the vehicles their on to violate many state and local laws.

Have great thanksgiving
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In all truths I would not recommend a long arm to anyone as you can buy a short arm 2.5" lift from metalcloak that will out flex any other lift offered that takes a fraction of time and cost to install and would have a superior ride on road and off.
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The Trail Runner is completely tunable by the end user as is every coil over or advanced system like that. I don't need to say anymore there. If you were a part of the tuning process well..... No need for us to be negative. That older system did not have the X2 Geometry for the rear that is coming out for Jan 1. It is very similar to what we have done on the JL and will make sure RK has a nice family of product.

You turned an open discussion on geometry into your opinion once again. A complete waste of time...

You too have a good Thanks Giving.
You brought up the trail gunner and no I wan not in on the tuning. Professional shop tuned but poor instructions and lack of phone support didn't help with your bypasses. Months down the road it turned out one bypass was bad but still does not ride good. I should track down the owner and try the ride again. He has installed tons on it now and I am curious how it rides with the extra weight. As far as geometry with the trail gunner, basically the same as your other 3 links rear and the front has too little separation at the frame side links, I am thinking it was between 3"-4". 25% rule should put you 7"-8" at the frame. I know the front is tough on geometry as there is just too much stuff up there but if you are going to have the rear links hanging as low as you do and using the low axle side front mounts why not drop the lowers a bit to gain some more separation and flatten the lower links some for less axle shift.

Why is it that you guys put out kits with all kinds of welding required and don't do anything with the lower control arm mounts to increase ground clearance?
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I know the rear isn't a good 3 link option but what about the front ?

Sent from my SM-N950U using Tapatalk
It works up front since you are one one side of the axle and have better placement of the frame side upper link mount. I prefer a 4 link up front though just for piece of mind not having to rely on a single upper link. Break that link on the trail and all kind of bad happens. I don't care for radius front either.
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Finally someone understands me. I'm running 35's on stock suspension w/ fender flares removed and heavily cut fenders front and rear. I get shit on often by the lift guys.
Yet off road & on road I have a smoother ride compared to those JK's I've ridden in that are lifted.
You are a smart man, don't get frustrated with the "JK bolt on crowd", they will learn someday that you can wheel with tires smaller then 40"
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Yet off road & on road I have a smoother ride compared to those JK's I've ridden in that are lifted.
Most assuredly, shitty lift kits result in shitty ride quality. But a JK can be lifted and IMPROVE ride quality at the same time. Just costs a lot of money and don't bolt-on.

... you can wheel with tires smaller then 40"
Without a doubt. But daily-drivin' sucks with tires smaller than 40". :grin2:
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The real problems that I see coming from store bought lifts, is the compromises that HAVE to be made working around all the factory bits and pieces. There's just no way around it. But, with a store bought lift, you're letting someone else make the compromises for you and, those may or may not be a compromise you'd have wanted to make on your own.

Educating yourself on how suspensions work can go a long way to help in making an informed decision in whether one companies compromises are more inline with what you're after, than another companies compromises. Being honest with yourself on the actual on road/off road time the rig will see, is something I think most people don't really do.

There was a great quote from a suspension design guru many years ago that makes a lot of sense and is simple. "Any suspension design can work if you don't let it move". That is so true.

Our problem is that we are wanting our suspensions to move, and move a lot. We want lots of up travel, lots of down travel, lots of ground clearance, and a low CG to boot. We don't want the front to lift or the rear to squat on climbs and we don't want the front to dive or the rear to lift dropping off things. We want tons of articulation off road with no body roll on road. We also want the axles to go straight up and down through they're range of travel all while keeping the pinion angle perfect and plunge on the driveshafts to a minimum.

That's a ******* tall order. You have to decide what's most important to you and go from there. Are you willing to cut and weld? Do you want to keep the Jeep pristine? Do you drive it to the trails or haul it on a trailer? Is it your daily driver or a toy?


There's a couple things on my build I did to facilitate the best of both worlds. They wont work for everybody, cutting is involved, but, I'll throw them out there anyway. One thing to keep in mind is that you only really need to use a very small amount of your total suspension travel on the street compared to off road.

Spring rates for articulation are too soft for street use, so I'm running 3 piece swaybars. I'll have a set of bars (low spring rate) for off roading and a big fat set (high spring rate) for the street. The big fat bars will eliminate the body roll on the street. It's two pinch bolts to loosen on the arms and pull out the bar, takes ten minutes. I don't even need to remove a tire to swap them out. This still gives a soft ride without the body roll, sway bars do nothing in two wheel bump.

I'm running bypass shocks. This allows me to have a set of street settings, in addition to crawling and go fast settings.

Compromises are easy, eliminating them is a lot of work, time, money, cutting, more cutting and more money.
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Bypass shocks don't give you multiple settings for crawling or go fast unless you change the bypass valves. They allow you to fine tune zones in the shocks travel. Tuning is very important when running coil overs and bypasses and I can't see just turning knobs based on crawling or driving on the street. With as heavy a rig you have I would not think you would be running a real soft coil either. I would think you would be running a 300/400 or greater.
With the adjusters cranked all the way in they essentially close the check valves and don't bypass at all. This will force all the oil to go through the valve stack, effectively creating a much stiffer shock. Bypass shocks are position-sensitive, not velocity-sensitive. I only intend to play with this on the short compression and rebound tubes......the ones closest to the valve stack at ride height. My thinking is that the zone on the street is going to be maybe 3" either side of ride height.

Right now I have 175/225lb springs for the front and 150/225lb springs for the rear, all 16" over 18". That's what Ryan from Accutune recommended I start with from his program. I told him my hunk of shit would probably weigh 6k. I've only tried slapping the fronts on so far, with 1" preload, and they didn't compress but for a couple inches. Obviously I won't know exactly what my rate will need to be until it's finished........but I have a feeling it will come in way under 6k.
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I understand how bypass shocks work, I don't get your thinking though. Crawling and street are very close to the same set up while go fast is where you need more compression and fast rebound. closing off the ride zone so it stiffens up makes no sense since you would be going from a stiff initial rate (ride zone)to a soft secondary (upper compressed) to a stiff third (bump zone) on the compression side and would want the shock to dump giving you a fast rebound. With go fast you would want a more progressive curve on the rates that restrict the oil flow as you hit bigger bumps. Of course your coils and psi in the shocks will have affect on the performance. Crawling would be the softest settings IMO so the suspension works and the coils don't lift the whole vehicle preventing articulation. On road you would be soft for comfort but also control body roll at speed so you find a balance there and you are addressing that with the swaybar system you are going to run. At the rates you listed your dual rate is around 90#-94#, if your unsprung weight was 4000# then you should have compression of 11 inches add 3" of preload should put you at 50/50 on a 16" travel shock. Not sure why you would only be getting a couple inches of compression on the fronts. My 2 door weighs in at 4000# of sprung weight I would guess you will be around 1000# or more with the amount of steel you have in your rig. I would think you would want to be closer t a 125# initial rate for mainly crawling and street and maybe a bit higher for go fast off road which you will typically see rates of 400-800 but these are purpose build for high speed, your jeep will never see these kinds of speeds. I know Ryan and he knows his stuff but I can't see you tune and set up a shock without knowing the weights of the car. Even a Couple hundred #'s will make a difference in shock performance. If you watch the ultra 4 guys race a short course and have a spare on the back is because it changes the performance.
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I told Ryan I thought my junk would end up around 6k, that was all me. That's all he had to go off of when he sent springs. The Jeep was/is nowhere near finished when I tried slapping on the fronts just for the hell of it. So it was much lighter than it will end up, and got me to thinking it will much lighter than my initial guess when it's finished.

Luckily, I believe Ryan does free spring swaps as long as the springs aren't all chewed up. So once the Jeep is finished (in 2034:thefinger:) I can give him the info of where everything sits and he can do his thing. I think I really overshot with the initial weight I gave him.
My JKU is in the shop currently getting a comp cut on front and rear fenders (no not the fender flares, those have been long gone)
I'm on stock suspension w/ 35's (really measure 33.5" but I digress)
The local wheeling club I go out with is shaking their head. But I'm determined to go 38's w/ 0" of lift after this comp cut front & rear.
Future plans will be coilovers w/ coilover hoops poking through the hood for, you guessed it, minimal lift. Maybe an inch? Time will tell. But the hood cut will be measured once we push out the front axle, in order for the coilover hoop to have room. Then the welding begins.

OP writing this thread has been such a relief to read. To know someone exists that understands LCG is really where it's at.
but I have a feeling it will come in way under 6k.
My fat ass of a Jeep somehow came in at ~5850. One tons and 40s, heavy ass rear bumper and a very light front. Thats it. No fenders or aftermarket sliders. Based on that I think you will be north of 6K by quite a bit. If you somehow come in under 5850, Ill book you a flight to CO so my Jeep can go on the gt1guy diet :grin2:


But I'm determined to go 38's w/ 0" of lift after this comp cut front & rear.
Have you seen Jeep's lower 40 build from years back? If you want to run 38s with no lift and want any sort of usable up travel, its going to require a bit more than a comp cut...
I think gt1guy is talking 6000# sprung weight, hell he has 400#'s of welding wire in the hood alone.:surprise: I would suspect the whole rig will be 7500-8000#'s
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My fat ass of a Jeep somehow came in at ~5850. One tons and 40s, heavy ass rear bumper and a very light front. Thats it. No fenders or aftermarket sliders. Based on that I think you will be north of 6K by quite a bit. If you somehow come in under 5850, Ill book you a flight to CO so my Jeep can go on the gt1guy diet :grin2:
I think gt1guy is talking 6000# sprung weight, hell he has 400#'s of welding wire in the hood alone.:surprise: I would suspect the whole rig will be 7500-8000#'s

Man I hope you guys are wrong. I fear you're not though.
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