Sunday, July 15, 2012

Choosing the Right Suspension System

Of all of the modifications I planned to make to my Jeep, the single most important and most difficult choice was which suspension system would be right for me.  One of the Jeep's biggest assets - its huge aftermarket support - can make it difficult to narrow down which combination of parts is best suited to any one particular owner's needs.  As I mentioned in my very first blog post, my Jeep's duty is as a daily driver, a comfortable road-tripper, and a capable 4 wheeler.  The challenge I faced was overcoming the fact that trail prowess and street performance are generally inversely proportional.

It was my intent to combine the best parts from across the aftermarket to build what I consider to be the perfect Jeep.  My definition of "perfect" is based on versatility.  My goal was to build a Rubicon Trail-capable Jeep with better-than-stock ride and handling on-road.  Working within a modest budget, was this even going to be possible?

Suspension kits for the Jeep are not created equal.  Budget kits create ride and handling shortcomings because they focus only on raising the ride height without correcting the suspension and steering geometry, while high-end kits often include expensive, superfluous components that are either overkill or simply not even needed.  I have plenty of experience building countless 4x4s over the course of my life and career and made my share of mistakes, but I wanted to build my Jeep right the first time.

If all I wanted to do was fit some taller tires, I could get by with nothing more than coil spacers and shock extensions.  This doesn't fit my needs though, because it does nothing to increase the suspension's performance off-road and it leaves out critical geometry-correcting components to address the on-road ride and handling compromises.  This might be adequate for a mallcrawler on a very slim budget, but I am unwilling to make compromises with my Jeep.

Once I determined what size tire and what type of tire I wanted for my Jeep, it was time to determine the amount of suspension lift I would need.  The Wrangler's generous fender openings provide clearance for 35's with only 2 inches of lift.  I found this minimal lift height quite appealing because it maximizes the Jeep's on-road handling, but I didn't want to sacrifice suspension up-travel and chassis clearance on the trails.  Conversely, I liked the idea of gaining additional belly clearance on my long-wheelbase 4-door Wrangler Unlimited with a tall suspension lift in the 4- to 5-inch range, but I didn't want to raise the center-of-gravity and compound the issues with the suspension, steering, and driveline geometry that result from excessive lift.  I also determined that my house's garage door clearance would allow my Jeep to be no taller than 4" suspension and 35" tires.  This meant that a suspension kit in the 3- to 4-inch lift range was my target.

If I was building a dedicated rock buggy or high-speed desert prerunner, there are countless high-dollar kits available to choose from.  However, I couldn't let marketing hype persuade me to dump big bucks into long-arm kits and remote-reservoir triple-bypass coilovers that would do little to help my Jeep's real-world performance.  The JK comes with long enough control arms to not suffer from the issues that the TJ, XJ, ZJ, WJ, and MJ do with their short arms, so a long-arm kit is completely unnecessary for my needs.  High-dollar coilover shocks are terrific for extended high-speed desert running, but absolutely unneeded for street, backroad, and rockcrawling duties.

I determined that I was shopping in the middle of the suspension spectrum, with an emphasis on geometry correction and spring and shock tuning.

I considered suspension kits from all the top manufacturers: Synergy, Teraflex, Offroad Evolution, Rock Krawler, TrailMaster, Pro Comp, Rubicon Express and Rancho.  After months of homework, I finally narrowed down my choices to the following three:

MetalCloak's 3.5" Game Changer suspension was almost the winner because of its incredible suspension travel, street-worthy ride and handling, and well-engineered control arms and DuroFlex joints.  I also appreciate the fact that it's American-made.  However, I felt that this kit was probably more suspension than I needed for my Jeep's intended uses, not to mentioned priced out of my league.  I wanted to be able to go to a highsteer setup with a flipped drag link and Reid Racing steering knuckles, but this suspension's incredible uptravel would cause steering interference with the Jeep's frame rail.  Additionally, I wanted to able able to keep my drag link and track bars parallel to the ground and as high as possible to raise the suspension's roll center to further improve on-road handling, so I determined this system wasn't my best choice.  Since making my final decision, MetalCloak has now released a more affordable system that combines their springs and other components with Old Man Emu's shocks.  With less suspension uptravel, the highsteer I wanted to be able to use would work perfectly with this kit.

ARB's Old Man Emu suspension suits my needs very closely.  OME notoriously provides a terrific on- and off-road ride because their Australian engineers design their suspension systems for long-distance overlanding across the Outback where rough, washboarded roads are the norm.  I have firsthand experience with OME's springs and shocks on several of my previous 4x4s and can attest to the superior ride they deliver compared to comparable systems.  Two of this kit's shortcomings are that it uses offset washers as a band-aid to correct the front axle's caster, and it offers no steering geometry correction so the drag link and track bar will cause the axle to move in a side-to-side motion as the suspension cycles up-and-down.  Both of these issues can be corrected with additional aftermarket parts, but I determined another kit to suit my needs even more perfectly.

American Expedition Vehicles' 3.5-inch DualSport ST suspension system provides almost everything I wanted from a suspension system, including being manufactured in the U.S.A.  I purchased it from Dave at Northridge4x4 and received some of the best customer service ever.  But why didn't I choose AEV's more expensive DualSport SC system, since it includes a drag link flip kit with trackbar bracket and the ProCal module?

These two additions are certainly necessary upgrades when lifting a Jeep and installing oversize tires, but I planned to install even higher-end parts for these two features: a Superchips Flashpaq instead of the ProCal, and a highsteer kit with Synergy's drag link flip kit and an upgrade to Reid Racing's JK steering knuckles with Synergy's chromoly tie rod.  More on those upgrades later.

There are a number of features that distinguish the AEV suspension from the rest.  AEV sums it up:
There are a lot of suspensions available, what sets yours apart from all the others?
In simple terms: OE-style tuning. With the benefit of a former Chrysler suspension engineer on staff, we began by optimizing all of the JK’s control-arm, track-arm and steering geometry to accommodate a lifted ride height. We then proceeded to develop custom coil springs and custom-tuned shocks. All of this development followed factory engineering methodology. The overall goal was to not only build a lift, but to create a fully tuned suspension that would enable a lifted JK to outperform a stock one in all driving environments.  We think we succeeded as AEV-equipped JKs not only have more wheel travel than stock ones, but can out corner them as well – and all without compromise to safety, practicality or comfort

Although the entire system is greater than the sum of its individual parts, each component stands out from the rest on its own:

Springs: AEV's springs are both progressive and frequency-tuned.  In other words, they get stiffer to support heavier loads as weight is increased to fight suspension sag when loaded down with a weekend's camping gear, and their rates are tuned to the Jeep's specific oscillation frequency which allows the suspension to naturally settle itself after a bump in the road.  Offloading this task from the shock absorbers allows the shocks to be better-tuned for their primary purpose.

Control arm relocation brackets:  These are one of the key components that makes AEV's suspension ride and handle better than any other on the road.  You can read more details of these brackets on AEV's website but to summarize it, the brackets reduce the control arms' angles for better ride quality and they adjust the suspension geometry to increase caster, reduce dive and squat, and minimize front driveshaft travel as the suspension cycles.  I really didn't want to have to deal with front driveshaft clearance issues and the expense of replacing it with an aftermarket unit.  Every negative trait of traditional Jeep suspension kits has been reengineered into a positive behavior with AEV's suspension.

Rear track bar bracket:  Much taller than any other track bar bracket on the market, AEV's track bar bracket raises the vehicle's roll center as high as possible to promote flat cornering, increases stability when the Jeep is off-camber on the trails, and eliminates the typical "tail-wagging" sensation from the rear of the Jeep when large up-and-down suspension motions are converted into yaw movements.  The raised bracket includes a forged replacement track bar that's shaped to clear the frame and exhaust.

At first I was apprehensive about re-using the Jeep's original control arms since most of the top suspension manufacturers supply new control arms with their kits, but after researching the available options, I realized that for most uses, the original control arms are all I need, and in most cases they are actually superior to aftermarket replacements (MetalCloak's control arms are excluded from this generalization).  Both AEV and Old Man Emu understand the benefits to retaining the factory control arms.  First, aftermarket replacement control arms are known for squeaking because of their inferior bushings; even Full-Traction Suspension's much-hyped Silent Ride System is notorious for squeaking.  Second, poor control arm geometry further increases the propensity for squeaky bushings.  To help us understand the extent of control arm geometry variation, MetalCloak created the following diagram that illustrates the superior geometry of their and the OEM Jeep control arms compared to a variety of aftermarket alternatives:

With all of these individual components working together, a Jeep lifted with AEV's suspension system outperforms any other suspension setup in nearly every terrain.  Expedition Portal's blog points to a great video that demonstrates the AEV DualSport suspension's capability on road and track.  This is not the sort of performance that Jeeps are typically capable of when fitted with a suspension lift, but AEV's superior geometry provides a clear difference:


Installing this suspension is incredibly easy.  I was able to install mine in my own garage in one day, with nothing more than a normal set of hand tools.  As mentioned earlier, I also installed some additional steering components that added to the total time to completion, but if you can follow AEV's thorough instructions and have a safe place to work, there's no reason why you should have to hire a shop to install this kit.  Truly the only challenging part of the installation was accessing the upper shock mounts for the front shocks to remove the old ones and install the new ones.  Bending and relocating the brake lines was a bit fiddly, but nothing that should be too difficult.

Some highlights from the installation:

Before the installation

AEV 3.5" DualSport ST suspension components

Yes, you can install this kit yourself! Begin with the Jeep's frame supported by jackstands

Brake hose drop brackets are included for the front and the rear

One of the key components is the ultra-tall rear track bar bracket

Front suspension assembled; new steering components discussed in another post

Control arm drop brackets installed on the far frame rail shows the minimal loss of ground clearance compared to the near frame rail without the brackets yet installed.  The reduced control arm angle plays a huge part in the AEV suspension's ride and handling superiority.

Installation complete, shown before aftermarket bumpers and other accessories were installed

As a baseline measurement, my 2010 Wrangler Rubicon Unlimited on the original 255/75R17 BFGoodrich Mud Terrain tires, original bumpers, and a hardtop measured 36 inches tall at the front fenders and 37 inches high at the rear fenders:

After installing the AEV suspension, Warn Stubby Rockcrawler front bumper, Warn M8000-S winch, and MetalCloak rear bumper and tire carrier, I drove the Jeep for several months and fully cycled the suspension on numerous off-road trips to ensure that the springs were fully settled to their final height before taking measurements at the fenders with the new 315/70R17 Treadwright Guard Dog tires:

The fenders now measure 41.5 inches tall front and rear, so by subtracting the 1.5 inch difference in the tires' radius, the actual amount of suspension lift equates to 4.0 inches in front and 3.0 inches at the rear - exactly what American Expedition Vehicles promised.  Accurate lift height estimates were critical in my case, because I calculated that my Jeep's hardtop would only have 0.75" clearance under my garage door opening with a 3.5" lift and 35" tires

Ride quality from the suspension is terrific, especially if you've ridden in other lifted vehicles.  The ride can best be described as smooth, but firm; it is similar to the factory tuning, but with much less "pogo-ing" over large bumps and frost heaves that significantly cycle the suspension.  The control arm drop brackets smooth the impact from small, sharp bumps, but the firmer shocks dampen the body motions that come from a higher center of gravity.  In my opinion, not only does the AEV suspension provide a better ride than other JK suspensions, it also rides better than a stock Wrangler with factory suspension.  The only real negative to the handling seems to come as a result of the heavy solid axles and 35" tires shuddering over medium-size bumps at high speed (such as a parking lot speed bump at 25mph) when the tires are inflated to street pressure; when aired down to trail pressure, the tires absorb enough of the terrain that this

The flat cornering and nearly nonexistent brake dive result in unbelievable stability at high speeds.  This is not an exaggeration.  Simply put, you would not believe a lifted Jeep could handle this well - especially if you're accustomed to an earlier TJ or YJ Wrangler.

Where this suspension really shines is at moderate speeds on rough, unpaved roads.  This was particularly evident to me during a recent trip across the Nevada desert, where I burned through nearly an entire tank of gas without setting a tire on asphalt.  We covered a wide range of terrain from low-range rockcrawling to full-throttle assaults on rocky, washboarded backroads.  A solid-axle Rubicon is no Ford Raptor, but the AEV suspension provides as much capability as the engine can deal out; on rough terrain like this with the tires at 20psi, speed tops out at 75mph in 4th gear (6-speed manual) while the tires and suspension absorb everything.  The tires left the ground on a couple of occasions, but I slowed to reasonable speeds through unexpected washes and not once did the Jeep crash off its bumpstops.

Despite what some Internet forum detractors might insist, AEV's decision to use Jeep's factory control arms does not artificially limit articulation while rockcrawling.  Of course high-deflection bushings in aftermarket control arms allow for additional articulation above and beyond what the OEM bushings will allow, but as a bolt-it-on-and-go suspension kit, AEV's setup pushes flex to the limits of not only the bushings, but also the brake hoses, the wheel speed sensors, the shock mounts, front and rear fenders, and the driveshafts.  If I was building a dedicated rock buggy, I could replace all of these parts, but I have yet to experience an obstacle where my Jeep's articulation has been a limiting factor.

The Corner Travel Index is the most accurate measurement of suspension articulation.  I had an opportunity to test my Jeep's flex at one of MetalCloak's Skillz Day events.  My Jeep's score was 735:

These tests are a great opportunity to check for problems at maximum articulation.  AEV's suspension proved to be well-sorted right out of the box, and pushes everything to its limits.  I found that my Jeep's rear tires kiss the end of the OEM Rubicon rock rails at maximum compression, and my highsteer drag link has 1/4 inch of clearance under the passenger-side frame rail at maximum compression.  At full droop, my brake hoses and wheel speed sensor lines are stretched to their limits, so I made a small tweak to the bracket to free up a little tension.  Driveshaft clearance is fine, although the joints will not tolerate much more suspension height.

Outside of a controlled environment, this simple bolt-on suspension's performance is even more impressive:

No matter how much suspension flex your vehicle has, you can always find obstacles that are extreme enough to lift a tire off the ground.  However, 40 inches of articulation is plenty for the real world.

One of the great things about AEV's suspension is that it can easily be upgraded in the future.  For instance, if you don't like reusing the original control arms you can easily upgrade to MetalCloak control arms.  If you want to take the steering to the next level you can easily upgrade to Reid Racing knuckles and Synergy highsteer.  The sky's the limit with AEV's suspension, but it performs flawlessly right out of the box.

My stated goal with my choice of suspension was versatility, and at this point the AEV 3.5 inch DualSport ST has lived up to its promise without costing an arm and a leg.  It has delivered on every promise made by American Expedition Vehicles' marketing - the suspension truly improves the ride and handling on-road while tremendously upgrading the Jeep's capabilities in all off-road terrain.

Along with the suspension, I have also upgraded the steering and front axle to further enhance the Jeep's handling and strength, but these mods are covered in other blog entries.  If you have any questions regarding the AEV suspension, please leave a comment below!


  1. Now that this is available which would u buy today between this and the Aev dual sport?

  2. I love the MetalCloak suspension, and I don't think you can go wrong with this kit; MetalCloak's springs and OME's shocks are second to none. The basics of this kit go about lifting your Jeep in a significantly different manner, however - more of a step in the right direction if you plan to upgrade to their full-boogie Game Changer suspension later on down the road. AEV's setup is basically done, right out of the box, but there's plenty of compatibility with other parts that future upgradability is nearly limitless.

    The AEV kit is better-suited to my needs. I really appreciate the improved control arm geometry that AEV's brackets provide, but they could always add those to the MetalCloak kit. However, I wanted to be able to run a highsteer setup with a drag link flip kit in Reid Racing's steering knuckles. I also wanted to be able to install Synergy's track bar reinforcement kit and sector shaft brace. These parts are pretty much incompatible with MetalCloak's track bar and won't work at all if you plan to upgrade later on to MetalCloak's Game Changer suspension kit.

    Since writing this original article, I have gone on to upgrade my steering. Check back soon for an article describing what I've done and what a difference it's made.

  3. If I simply want the same factory functionality of the rubicon but a 2 inch lift to allow for bigger wheels would u recommend anything different than AES 2 inch lift w 285 70 17 guard dog tw tires?

  4. AEV's 2.5 inch lift would be a great option, but could be overkill for those 33x11 tires. If you're just looking to gain a little clearance and improve the looks of your Jeep while keeping everything as close to stock as possible, I would simply install a leveling kit or "budget boost" kit that retains the original springs and shocks. Something like this kit from Teraflex:

    I definitely think you're on the right track with those TreadWright Guard Dog tires. You can read my initial impressions of mine here: I am still extremely pleased with them after 8,000 miles of daily driving and offroad use in all terrains but snow & ice. That'll soon be tested though, and the benefits of the Kedge Grip will soon be put to the test.

  5. Aev has a 2 inch spacer lift but I'm not sure if I should go up to the 310 or stay w the 285

    1. Yes, AEV also has a very nice 2.5" spring lift. If I was doing either of these lower suspension lifts, I would probably have gone with a 255/80R17 tire instead of a 285/70R17. There aren't as many to choose from in the tall/skinny 255 size, but it is a really effective size for most types of terrain.

  6. Nice writeup. Saw your link to this from JKO. I have a 2012 2Dr Rub with a 6 speed. If I go with this same kit as you, do I need to get anything else? Front drive shaft? Tie Rod?

    Just need to make sure I plan everything out.


    1. The 2012+ Jeeps need a new front driveshaft and/or exhaust spacers/Y-pipe for clearance with anything more than 2.5 inches of lift. Other than that, this kit will be everything you need!

      AEV offers their own steering correction kit, but I chose to upgrade mine further with steering parts from Synergy and Reid Racing. After adequate testing, I'll be reviewing those parts too. But so far, it's been flawless.

  7. Choosing right and good quality suspension system for our creating such a big Dell-ma.You are updating some interesting and valuable points over the suspension system.It helpful for all kind of automobiles users.Thanks for sharing us such useful one.

  8. With 8,000 miles on the suspension, the only thing that's left me dissatisfied is the damping level (ride quality) of the Bilstein 5100 shocks. It is great for rockcrawling and blasting down desert trails at high speeds, but at more moderate speeds and while daily driving on the street, I found the Bilsteins to be excessively firm. They provide great handling, but the ride suffers.

    I have now replaced the Bilsteins with a set of adjustable Rancho RS9000XL shocks. Instead of being forced to compromise in most real-world terrain by having a preset firm ride, I now have shocks that are easily adjustable to nine different settings. While daily driving I can have a nice plush ride, but while rockcrawling or loaded down with tons of extra gear I can firm them up however I want them to be with the simple twist of a knob.

    For comparison's sake, the Ranchos on their firmest settings (8 or 9) is roughly how the Bilsteins are valved, which is perfect for high-speed trails and for maximized body motion control while rockcrawling. But for daily driving, I have found that my long-wheelbase Jeep with bumpers, a winch, and tire carrier is best at setting 1 in front and 3 in back when the hardtop is installed, and 1 in front and 1 in back when the hardtop is off. The superior suspension geometry of the AEV DualSport kit allows me to get away with plush damping because the chassis doesn't rely upon the shocks to keep the body settled. Other suspension setups may have excessive brake dive, acceleration squat, cornering lean, and head toss at these softer settings, but that's the beauty of the Rancho 9000's: you may adjust them to whatever level YOU prefer, instead of being stuck with whatever arbitrary valving the shocks' engineer chose for you.

    I found the external build quality and overall beefiness of the Ranchos to be superior to the Bilsteins. The design of the top post on the front Ranchos is also superior because Rancho has provided both a male hex and a flat for a wrench to keep the shaft from rotating while torquing the stud nut; installation and removal of the Bilsteins is much more challenging because the only provision they provide for a tool to keep the shaft from spinning is a small female hex at the end of the stud, which would be okay if there was actually room to get a standard hex tool into it. I had to cut down one of my hex wrenches just to fit it into the shock, and even then it was still a much more challenging install than it should have been. Rancho provides a much smarter solution.

    The quality of the Bilsteins' rear cross pin is a bit better than the Ranchos', but even if I had a problem with the cross pins, they're considered disposable and there are plenty of superior aftermarket alternatives available.

    The only significant difference in which the Bilsteins should perform more consistently is in extended high-speed rough-terrain driving; the high-pressure nitrogen charge will help prevent shock fade better than the low-pressure nitrogen charge in the Ranchos. The single-wall (monotube) design of the Bilsteins also helps radiate heat from the fluid better than the double-wall (twin-tube) design of the Ranchos, so if extended high-speed runs across the desert are your thing, the Bilsteins might be a better choice.

    While we're talking about the monotube versus twin-tube designs, it's worth mentioning that a single small dent in the monotube Bilsteins can ruin them, while twin-tube Ranchos are notorious for shrugging off multiple large dents. The twin-tube design protects the cylinder in which the piston travels from damage to the outer wall of the shock, while the outer wall of a monotube shock is also the inner wall; a small dent in a monotube shock body will shred the piston seal, while a large dent can prevent the piston from moving. If rockcrawling is your thing, a monotube shock is usually a better choice.

  9. Jeep Shocks are needed to absorb the energy from bumps and rough driving conditions by keeping the drive as smooth as possible. Jeep Shocks should be replaced at a maximum of 50,000 to 75,000 miles. Replacement of shocks depends on the specific model of your Jeep.

  10. Awesome! The suspense lifting is the perfect solution for off road trucks. They can ride through the rocks without any problems when they are lifted this high. The Suspension lift is a must have for every off-road lover.
    Fabtech Suspension

  11. Those are really interesting updates and good points on the suspension system.Very handy helpful for all kinds of automobiles users.Thanks for sharing .

  12. Thanks for your blog. I was wondering have you thought about getting any control arms yet? I was wondering if it makes any sense to have the AEV brackets and control arms? With slightly longer then stock arms and the AEV kit would it act like a mini long arm kit? Or would the angles be all wrong?

    1. When my suspension out-flexes the OEM control arm bushings and wears them out, I will definitely be upgrading to the MetalCloak control arms. They'll allow me to push my rear axle back a little bit to properly center the rear tires in the wheelwells and gain enough room to fit 37's with no more suspension lift.

  13. Hey again check out metacloak is selling this in exchange for a 1oz gold coin... spot gold prices I can get a gold coin for 1500 and it's a 2000 suspension system... this is tempting!

  14. I have watched a lot of articles regarding information for Truck on leveling kits, Suspension and other parts of a Truck for customization.
    I found similar website which has similar information and also a lot of lift kits and other information. The information of is really attractive rather than I found from local market.

  15. Hi, i follow your blog for some time and first off all i want to congrat you for your posts and ideas.
    I'm from Portugal and owner of a 2 door wrangler JK from 2010 i first install an Teraflex 2.5" and i few mouths ago remove it.. it sucks really!!!
    I want to do a new project from scratch and in the post i fund some good and share ideias.
    I'm wondering if you can help me to choose parts because like i'm from Portugal and i maybe going to buy in US i must choose wisely because of transportation and taxes...

    Happy to ear from you, Regards from Azores, Portugal

    1. I'm saddened - but not surprised - to hear of your dissatisfaction with the Teraflex suspension - I don't have any firsthand experience with Teraflex's products, but I've seen some really cruddy Jeep steering linkage that was claimed to be theirs, and I think they're total douchebags for their recent outright copy of Reid Racing's steering knuckles. Let's just say I don't plan on ever using any of their parts on my own Jeep.

      As the article above elaborates, finding the right lift kit isn't easy. I'm still absolutely in love with the AEV kit - I haven't ever had a single problem or criticism since I installed it, and others who have driven my Jeep are consistently impressed with its on-road manners. If you like the 2.5" lift height, I'd recommend AEV's 2.5" kit. Rancho Suspensions is another to consider since they now have a variety of suspension kits to choose from, including some control arm relocation brackets similar to AEV's that will ensure your Jeep drives better with the lift than in stock configuration.

  16. Happy for your response.
    Do you have some place to chat?

    1. If we discuss here, then other Jeepers can benefit from the information.

  17. This comment has been removed by the author.

  18. Sure, sounds good.
    Ok i will put here my ideias.

    I had 3" Teraflex so maybe the 2.5 was ok but i'm going to put min 35" tires and some near future 37" so i think will be better 3.5".
    My fisrt reason to really think about AEV or Metal Cloak is about the Dual Rate Springs (please your feedback) second reason and pushing to MC is about the control arms with the new system.
    I understand that like you said AEV is a wonderful system to work on from zero if want more the the AEV stock.
    I'm going to put here my ideia and hoping some comments about it and if worth it.
    I wanted to do like you, install Reid Knuckles, Synergy Jeep JK Chromoly Tie Rod, Synergy Jeep JK Front Steering Correction Kit etc, Currie Swaybar for the back, MC arms control... it is some ideias to apply on AEV system.
    So something like this worth it instead MC Game changer for instance.

    Sorry my English, and best regards from Pico.

  19. It will take quite a bit of work to fit 37" tires with only a 2.5" kit. My AEV 3.5" kit flexes enough to completely stuff my 35" tires into the wheelwells, so longer bumpstops and fender trimming would be required to fit a set of 37" tires. You could always install 1-inch coil spacers above some 3.5" springs at some point in the future if you plan to upgrade from 35's to 37's.

    If cost isn't a big deal, you can't go wrong with MetalCloak's suspension. To further improve on-road handling, you can always add a set of control arm relocation brackets from AEV or Rancho, but keep in mind that MetalCloak's GameChanger kit does not allow you to fit a drag link flip kit or the Reid Racing steering knuckles, so you will have some minor steering compromises if you go with the GameChanger. However, if you go with MetalCloak's Overland kit with the Old Man Emu shocks, you can absolutely do the Reid knuckles and drag link flip kit with no steering-to-frame interference issues.

    I wouldn't bother with the Currie sway bar for the back, unless you've found some reason why you really need to fine-tune the rear-end's suspension articulation.

  20. On a quick research, the AEV Kit plus MC arms is a litle more expensive that buying a not game changer MC suspension with the arms. Sure thats the real deal because i'm buying all at the same brand. So if i want the MC arms i'm better go with the MC's Kit like you said above they lunch this lite suspention when you choosing the AEV, do you have feedback for the dual rate springs like the arms of MC? The socks, well if i buy the kit i'm going to use them OMU or Bilstein and after upgrade to others like i was thinking using FOX or Better Bilstein.

  21. The MetalCloak "Lite" suspension with Rancho or AEV control arm relocation brackets, adjustable Rancho RS9000XL shocks, and a Synergy drag link flip kit on Reid Racing steering knuckles would be an awesome combination of parts! I didn't like the Bilstein shocks that came with my AEV kit - I found their ride quality was way too stiff so I replaced them with the adjustable Rancho shocks and I couldn't be happier.

  22. Ok, other view, rockkrawler 3.5", 3 link and the rear axle has been moved back 3" to "provide a perfect 99" wheel base" it's a another championship?

    If you ask what i going to do with my jeep, it's all things, road, krawling, expedition.

    1. I'm not particularly impressed with the Rockkrawler suspension, due to the choice of bushings and linkage they use. I don't think you gain much performance for all the cost and effort involved in extending the wheelbase 3 inches. I think you would be better served by the 3.5" AEV, 3.5" MetalCloak Lite, or 4" Rancho Sport suspension kits. For your Jeep's uses, I definitely recommend Old Man Emu or Rancho RS9000XL shocks.

  23. I'm spend some time looking and searching, i'm almost decided to:, maybe with OME and later upgrade or the other and choose FOX, but for now and spend less... i'm thinking OME i now they are great i had one set and have friends with them.
    The other parts are that steering upgrades. I'm going to try if they sell that kit without the front and rear track bar or really stay with them... they fit on synergy products don't they?


    1. I would recommend talking with Will at MetalCloak - let him know you want the GameChanger OME kit but that you want to run Reid Racing highsteer knuckles. He can help you customize the kit so you get all the right parts and still be able to raise the steering linkage and track bar.

  24. Did your change your gears @ rubicon4wheeler?

    1. No, I haven't. The Rubicon model's 4.10 gears are perfectly matched to the 6-speed manual transmission when running 35-inch tires.

    2. I'm glad I came across your blog @rubicon4wheeler. Reading this blog was like you were reading my mind, and exactly what I was looking for in a suspension lift for my driving needs and occasional wheeler. After months of researching, reading forums, picking peoples brain and changing my mind back and forth I had narrowed it down to AEV and BDS suspension. Reason for that is because I have a well experience with BDS and had purchased and installed it on my 2000 TJ, also I like their lifetime warranty. However, after reading your blog I have pulled the trigger and purchased the AEV 3.5 DS sc. Just before I decided to go with AEV I had a conversation with a colleague and fellow wheeler. He runs a teraflex 4" lift with adjustable control arms. Furthermore, he strengthen the fact that if I'm running 35's I would need to change my gears to a minimum 4.88 or preferably 5.13, which he's running, due to the "fact" that he lost his 5th and hardly used his 6th gear just before he changed his gears. He also stated that I should at least change my front drive shaft. Have you had any issues with your drive shafts? also, are you currently running without a steering stabilizer? sales rep where i bought the AEV lift adviced and recommended to never run without a stabilizer.

    3. I have to disagree with your friend and his insistence that you change the gear ratios. You didn't mention what year your Jeep is or which transmission it has, but that plays an important part in answering your questions. I have a 3.8-liter with a manual transmission and the 4.10 gears that come in the Rubicon model, and I absolutely do NOT need to regear it. Freeway hills that I used to have to downshift for in my 4Runner, Sidekick, and Samurai are a breeze to climb in the Jeep's 6th gear with no drop in speed. But if you have the 3.8-liter with an automatic transmission, it will be downshifting for just about any hill with 35-inch tires and the Rubicon's 4.10 gears. If you have a 2007-2011 non-Rubicon with 3.73 or 3.21 gears you'll be in even worse shape. But the newer Jeeps with the 3.6-liter engine will have no problems with either the 5-speed auto or the 6-speed manual. If you're going to regear from 3.21 or 3.73 it doesn't make sense to go to "only" 4.10 gears - you'd want to go to 4.88's. Unless you're running 37-inch tires or taller I wouldn't recommend going to 5.13 gears, especially considering the fact that as you go deeper in your gear ratio, the pinion gets smaller and the overall strength of the ring and pinion gearsets drops. Regarding your friend's recommendation about replacing the front driveshaft, that is only required on 2012 and newer Jeeps with the 3.6-liter engine; Jeep relocated the exhaust crosspipe on those Jeeps into a location that interferes with front axle downtravel when a lift kit is installed, and the driveshaft on those models contacts the exhaust. The 3.8-liter Jeeps do not have this problem, so I'm still using the original driveshafts and have never had a single problem. As far as a steering damper is concerned, I've driven my Jeep without one and there was zero bumpsteer or death wobble or anything like that. But as automotive engineers unanimously agree, a steering damper is a good thing, especially in offroad terrain where trail obstacles can jump out and grab a tire as the vehicle is moving, which can force the steering wheel to suddenly spin out of control and possibly spraining a thumb in the process. For that reason, I reinstalled the original steering damper. I haven't finished writing my article on all the steering upgrades I've made since installing the AEV suspension, but I'll tip you off by saying the balljoints, drag link flip kit, tie rod, track bar, track bar bracket, and sector shaft reinforcing bracket I got from Synergy Suspension, the Reid Racing heavy-duty steering knuckles, and the Artec axle truss kit have made for a nearly bombproof front-end that steers much better than stock.

    4. My apologies for not being clear on the year and model. I have a 2013 JKU Rubicon with manual transmission. Since the last time I wrote on the Blog I purchased the AEV 3.5 dualsport lift and had it installed by the Tire place where I purchased my 35X12.50 BF goodrich KM2's. Reason for choosing the KM2's is because my jeep came with them and I like how they ride and feel and very little noise. I installed the tires on my stock rubicon wheels with 1.5" spyder trax spacers, However the tires are rubbing a little at where I believe is the swaybar but only when I turn the tire all the way. wondering if you were experiencing this?

    5. I haven't heard of this being a problem. Many people use this size tire with OEM wheels and 1.25" wheel spacers and don't have rubbing problems. With another 1/4-inch of clearance, you shouldn't have any rubbing. I have no rubbing with my Spidertrax 1.5" spacers and 35x12.50 tires. Maybe you're getting a little more steering angle out of your front-end. You could solve the rubbing problem by installing some Reid Racing steering knuckles like I have, and then grind down the steering stops to exactly where you need them to be to keep the tires from rubbing at full steering lock.

  25. Great write up. I didn't see any mention of spacers or mods to the exhaust to clear the front drive shaft, did you have to change anything or is it all still stock.

    The reason I'm asking is because I just had the same kit installed yesterday and the dealership said that in most cases,it was not needed.

    1. Only the 2012 and newer Wranglers with the Pentastar 3.6-liter engine require exhaust spacers or new Y-pipe for clearance between the exhaust and the front driveshaft. The 2007-2011 Wranglers have a different exhaust crossover pipe with plenty of clearance for suspension downtravel and the corresponding movement of the front driveline.

  26. I have had the aev 2.5 for one year on my 12 Jku with 315 duratracs. The ride has progressively gotten worse to the point I absolutely hate driving this jeep. There is no dampening from the suspension. I feel that the shocks are blown. With that said, the bilsteins do ride like shit and I'm about to pull the trigger on some rancho 9000s. My research from Internet alone shows 7 people who love it (switching from aev spec), and one person who didn't feel the difference driving on shitty pothole roads. I imagine any shock at this point would do me better and I'm not even interested in replacing with new bilsteins.rubicon4wheer, Do you still like the ranchos?

    1. Assuming you haven't increased the air pressure in your tires, the most likely cause of your deteriorating ride quality is the shocks. Typically as a shock absorber wears out, it will lose its damping abilities and will result in a softer ride, but the valves within your shocks may be sticking closed and preventing them from working properly. I would definitely recommend contacting AEV to see what recommendations they might have; perhaps they will replace your shocks under warranty. I never liked the ride quality of the Bilsteins so I sold them and upgraded to the adjustable Rancho RS9000s. They provide a much smoother ride on the road and at lower speeds, while still having the ability to be set for firm damping when needed: while carrying a heavy load, towing a trailer, rockcrawling, or covering rough terrain at high speed. The adjustability isn't a gimmick - their adjustment range goes from extremely soft to even firmer than the Bilsteins. The Ranchos also have a lifetime warranty so in the event you ever have a problem with them, you're covered.

  27. Hello,

    I have a 2012 2dr Rubicon 2.8 CRD (Diesel) and am planning to do exactly as you did: AEV 3.5” lift with stock wheels and spacers.

    But I have some questions to which I hope you might help me with some answers from your experience and knowledge:
    1. Having in mind that I have an automatic diesel, do I have to regear for max 33 inch tires to have stock performance?
    2. What tire size would you recommend 265/70/17 or 285/70/17? I care more about how it drives (on and off-road) than how it looks.
    3. How much does the additional weight (tires & wheels) affects axels and other components if I go with bigger tires?

    Please excuse my English.
    Thanks for your reply!

    1. With the torque of your diesel, I seriously doubt you will have any problem with your original gearing for 33-inch tires. The additional weight of the tires won't be significant enough to affect your axle and suspension components - remember, these Wranglers come with 32-inch tires right from the factory, so a 33-inch tire isn't going to be problematic. In fact, with this much suspension lift, you might find that a 265 or 285 is too small a tire. If you want to keep the weight down and maximize street performance, the tire size I would recommend is a 255/80R17. This will be about 33.5 inches tall so it will fit your suspension height much better and provide better ground clearance, but it will be lighter in weight with less rolling resistance.

    2. Thank you very much for your reply!
      Maybe indeed 3.5" is too much for me, what do you think about 2.5" with the high steer kit and geometry correction brackets(AEV)? would it be exactly the same as the 3.5" kit (of course, beside the 1" height difference, procal and jack-base) or do I need some other parts to reach 3.5" SC performance?

    3. The 2.5-inch kit would be more appropriate with a 33-inch tire. The AEV geometry correction brackets have mounting holes for 2.5, 3.5, and 4.5 inch lifts, so everything will be proper. You can still benefit from Reid Racing highsteer knuckles as long as you use the proper front bumpstop spacers to keep the drag link from touching the frame when the suspension is fully compressed. I would also recommend installing Rancho RS9000XL shocks instead of the Bilsteins, because the Bilsteins that come from AEV are tuned very stiff. I did not like the ride quality at all so I replaced them with the Ranchos, and now I can adjust the ride quality to however firm or stiff I would like it to be.

    4. Hello again,
      so, basically, you would recommend the following:
      1. AEV 2.5inch lift-kit;
      2. AEV geometry correction brackets;
      3. to switch the Bilstein's shocks with the Rancho's.

      And a further improvement:
      Reid Racing highsteer knuckles with the Synergy high steering kit and maybe Metalcloak's control arm set.

      Did I get everything right?:)
      Thanks again very much!

    5. I'm still using the original control arms and haven't had any problems with them or with their bushings wearing out. But once they have worn out, I will upgrade to the MetalCloak control arms. I wouldn't say you need to worry about replacing your OEM control arms immediately unless you really want to.

      As for the AEV 2.5" kit (it comes with the geometry correction brackets) I would definitely recommend it. If you like a firm ride, the Bilstein's are quality shocks. If you prefer a more compliant ride, or would like the ability to fine-tune your suspension's performance, then I absolutely recommend the Rancho RS9000XL shocks.

      Correcting the steering geometry is ideal, and raising the steering linkage up and out of the rocks is obviously beneficial. The stronger Reid Racing knuckles work with any drag link flip kit; I chose the Synergy kit for their stronger chromoly tie rod and drag link, and I knew they would work perfectly with the Synergy track bar and their kits for the track bar mount and steering box sector shaft reinforcing kit which I also recommend. These upgrades produce an incredibly stout front end with steering that is noticeably better than stock despite the higher ride height.

  28. For the best ride Nd in road handling do u recommend. Specific tire?

  29. Love your article. I have a 15 Rubicon Hardrock Unlimited with an automatic, 3.73 gears, 35 Duartec tires on the stock Rubicon wheels with spacers and the Smittybilt XBR Body Armor Fenders. I intend on rock crawling on the weekends and using it as a daily driver during the week. Would you recommend the 2.5 or 3.5 AEV OR the Metalcloaks cheaper alternative you posted in your article for me? I appreciate your opinion.

  30. You can't go wrong with either AEV or MetalCloak. I'd recommend the 3.5" lift since you have an Unlimited - the long wheelbase is the 4-door Jeep's Achilles' heel with its long breakover angle. I definitely didn't like the AEV Bilstein shocks because their ride was punishing. I replaced them with Rancho RS9000XLs and absolutely LOVE their ride and control, but you can't go wrong with the Old Man Emu shocks. I'm inclined to recommend getting the MetalCloak kit, and adding the control arm geometry correction brackets from either AEV or Rancho.

  31. Where do you purchase this lift now? I can't seem to find it....

  32. HI,

    Nice discussions here and appreciate the knowledge sharing. I haven't come across a discussion like this in any forums. I think you are the exact person I was looking for :)
    I have a JKUR 2014 and was running a teraflex 2.5" coil lift with shock extensions. Now I have ordered the 3.5 game changer with 6 pak shocks.
    Since I am running 33x12 tires with stock fenders. Metalcloak recommends their fenders to make full use of their 6 pak up travel, but that is generally for 35" tires or bigger. From my discussions with Metalcoak and reading in forums I am assuming that 33" tires with 2" bumpstop is what I will end up with stock fenders. I don't know if that will the full use of the 6 pak shocks or no bumpstops will be the full use. If I end up with 2" bumpstops, I am also thinking of adding 1" teraflex spacers to get a little more height for both belly clearance and reducing bumpstop height to use full potential of the 6 pak shocks.
    Is my plan correct.


  33. Thanks for the excellent write up. I'm very interested in doing something similar to what you've described here. It seems the AEV DualSport ST 3.5" kit is no longer offered. From what I can tell of their current offerings, the DualSport XT looks like it is the closest thing to the DualSport ST setup that you purchased, however the XT is only offered in a 2.5" kit. Their current 3.5" kits (SC and RS) seem to include many more components than the kit that you purchased, likely making them quite a bit more expensive, although I'm not sure what you put into your kit at the time of purchase. However, I'm going to make what I think is a correct assumption that the current 3.5" offerings are quite a bit more expensive than the DualSport ST kit you've got. Given this, would you recommend going with the newer MetalCloak kit that you mentioned above and adding the geometry correction brackets from AEV?

    1. MetalCloak actually has their own geometry correction brackets now! Since the AEV-specific Bilstein shocks are so stiff (necessitating replacement with Rancho RS9000XL shocks) and the AEV springs have sagged (necessitating replacement with MetalCloak's 3.5" springs) I'd recommend just getting the MetalCloak Overland suspension kit.

    2. Thanks for the info on the lift. I just got my first jeep it is a 2016 Wrangler Unlimited Willys Wheeler W (auto trans) and I love it. It is my daily driver but I'm going to be doing trails too. I live in OH so not a lot of rock crawling opportunities, but I do like the idea of having an up-gradable suspension and you post is full of great information that is easily digestible for a noob (you don't always get that on forums).

      Based n your article my plan is to upgrade to 35s with a 3.5 lift using the following: MetalCloak Overland 3.5 Elite Suspension kit, Rancho RS9000XL shocks, Reid Racing highsteer knuckles with the Synergy high steering kit, MetalCloak Duroflex Control Arms, and regear to 4.56

    3. I've been happy with my AEV-based suspension, but given the rough ride with their Bilsteins and the problem with their springs sagging, I would do exactly what you're planning to do if I was starting over from scratch on my own Jeep.

  34. This comment has been removed by the author.

  35. Hi, I am planning to install a 3.5 inch rubicon express lift kit on my 2016 2 door jeep jk, and Rancho RS9000 shocks. However I am confused with which are the right part numbers of the Rancho shocks I should get. Some say I should get the RS999329 and RS999330, but others say I should get RS999331 and RS999332. I am so confused. Could you please help me out?

  36. Hi, thanks very much for the great write up:)

    I'm trying to decide what suspension kit/set-up to go for on a 2007 2dr Rubicon and being used as a daily driver, but also looking for much improved off-road performance over my Mk2 Pajero (which is on 33's, 2” suspension lift and 2.5” body lift). I'm based in the UK so would need r/h drive parts! The vehicle will be used for 'green-lanes', 'pay and play' off-road sites and off-road trials events.

    Firstly, I like the idea of fitting 35's, but if that would mean changing more parts and much more expense then I'd probably stick with 33's - any advice on this please?

    I have been advised that I could run 35's on a 2.5” lift. If this is the case, I may well go with a 2.5” lift, use 33's initially and see how I get on with the option to change to 35's if necessary. But, would a 2.5” lift allow 35's?

    Is there any off-road performance increase in using a 3.5” lift over a 2.5” kit? More articulation?

    After reading your blog, the AEV kit sounds good, but I'd be concerned with the firm ride of the Bilsteins that it comes with and wouldn't really want to have to replace the shocks straight-off!

    I also liked the look of the Metalcloak Gamechanger kit and the increased articulation it offers, but this looks more expensive and no UK distributor from what I can see.

    I have also seen an OME kit (2.25”) which presumably with give a better ride quality that the AEV with Bilsteins, but you mention this isn't the best set-up to get good geometry.

    If you're able to give me any advice please as to which way to go, it would be very much appreciated.

    Many thanks

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