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Lifted Jeep JK Alignment

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Jeep JK AlignmentOn a stock Jeep JK, you have very few adjustable components when it comes to wheel alignment. The Control arms are not adjustable, the track bars are not adjustable, the ball joints are not adjustable, it has a straight axle so there is no camber adjustment.  The drag link and the tie rod are both adjustable which will allow an alignment shop to center your steering wheel and set the vehicle's wheel toe and that's about it aside from taking your money.

Unlike the previous model of Jeep Wrangler (the TJ), the new steering design on the Jeep JK Wrangler, requires just a few adjustments with regard to alignment after the installation of a small to moderate suspension lift (2″-2.5″ of lift). The JK steering geometry does not change much at all with 2.5" of lift or less.  Sure, your axles will be slightly off center unless you install adjustable control arms and your caster might be just slightly off unless your lift came with adjustment washers. Your wheel toe will not likely need to be adjusted at all unless it has already taken a pounding on the trails.

Of course, if you install a taller lift that includes more adjustable components, you will be able to make several additional and more precise adjustments that will allow you to fine tune things such as pinion angles, wheel base and caster.

CENTERING THE STEERING WHEEL
Installing any amount of additional lift on your Jeep JK Wrangler will require you to re-center your steering wheel. The more lift you add, the more off center the steering wheel will be.  An adjustable front track bar will minimize this to a certain extent but, you will still need to re-center your steering wheel.  When the steering wheel is not centered,  it will cause your ESP (Electronic Steering Program) to react as though the vehicle is in a slide. The ESP will attempt to compensate by activating your BAS (Brake Assist System). The BAS is designed to optimize the vehicle's braking capability during emergency braking maneuvers. Having optimum brake pressure applied is a good thing when needed it but, it can be dangerous when you don't.

CENTERING THE FRONT AXLE
Any amount of suspension lift on a Jeep, or any vehicle with a straight axle, will shift the front axle toward the driver's side of the vehicle and the rear axle toward the passenger side.  The amount of axle shift is directly proportionate to the amount of lift you install. Installation of an adjustable track bars are necessary to precisely center the axle under the frame.

NOTE: If you install a lift that exceeds 3",  your axle positioning and steering geometry will both require correction in order to maintain good handling, drivability and steering. This will require an adjustable track bar, a track bar relocation bracket and a drag link flip kit. The drag ling flip kit relocates the drag link to the top of the steering knuckle on the passenger side and must be installed at the same time as the track bar relocation bracket to maintain proper steering geometry.

NOTE: Many aftermarket track bars utilize the existing OEM bolt which is fully threaded. We recommend that this bolt be replaced with a shouldered bolt of the correct diameter so that the threads don't oval out the bracket holes and the bushing sleeve. A loose track bar usually results in loose or flighty steering and in worst case scenarios, DEATH WOBBLE.

SETTING CASTER ANGLE
If you have chosen to install a lift kit of 3" or taller on your Jeep JK Wrangler and intend to run 35" tires or larger, your caster angle will most likely have been altered  enough to cause a "flighty" or "wandering" steering sensation when driving at highway speeds.
 
When a vehicle's front suspension is aligned, caster angle is adjusted to achieve the self-centering action of steering, which affects the vehicle's straight-line stability. Improper caster settings will result in a need for the driver to move the steering wheel both into and out of each turn, making it more difficult to maintain a straight line.

To address this issue, it is necessary to bring the caster angle back closer to the factory setting of +4.2°. More positive caster will help your Jeep drive a lot straighter and will reduce or eliminate the vehicle's  tendency to wander entirely but, if you are running the stock OEM drive shafts, there is a possibility that you might develop drive line vibrations, especially on taller lifts

The most favorable way to adjust your caster angle is to install a set of adjustable front upper and lower control arms. The lowers would be used to reposition the axle properly under your Jeep and the upper control arms allow you to set the caster angle. If you're on a budget, you might consider installing control arms in stages purchasing the front upper arms first but, you will need to make sure they can be set short enough to provide the results you need. You can purchase the lower control arms later. Cam bolts can also be utilized to provide more positive caster if you are on a tight budget but, they are certainly not the best or most durable option.

Upper and lower control arms are installed using the same principles. The only difference is that you would adjust the upper arms short than the stock arms and adjust the lower arms so that they are longer than the stock arms.

NOTE: The slope of most public roads and highway surfaces toward the outside which allows for proper drainage is referred to as ROAD CROWN. Excessive road crown can cause a straight axle vehicle to pull to the right. Slightly increasing caster on the right front wheel is sometimes done to compensate for road crown.  Without caster being set a bit higher on the right side, you will often notice that the vehicle tends to wander to the right.

CAMBER
Camber is the angle that the tires are at from top to bottom when looking at the vehicle from the front. Camber is Typically slightly negative (The top of tires tilted slightly inwards). Very few if any vehicles  have factory specs that require positive camber (the top of tires tilted outwards), but some vehicles do allow enough adjustment or tolerance to allow a small amount of positive camber though it’s not recommended.

That being said, camber is NOT adjustable on Jeep TJs or JKs without special offset ball joints. If your jeep's camber is severely off, it is very likely that you could have a bent axle housing. You should always be sure that your axle housing is indeed straight before purchasing expensive aftermarket ball joints.

WHEEL TOE SET
Toe set is the most common measurement associated with front wheel alignment. Normal chassis and linkage wear, in addition to the beating that many Jeeps get on rough trails, make toe-set something that should be checked and corrected on a regular basis.

Toe-in is the precise angle of the front wheels when the steering and wheels aim straight ahead. To most people, having your front wheels exactly parallel to each other would seem ideal but in fact, the front wheels seldom sit at a zero-degree toe set. Typically, the front of your tires point slightly inward . This is called a "toe-in" and, on a rear wheel drive vehicle, it is deliberately set this to help keep your Jeep driving straight and proper toe setting will result in more even tire wear.

TOE does NOT cause a Jeep to pull in one direction or the other. You simply set the toe to spec by adjusting the tie rod and then center the steering wheel with the drag link (the drag link does not affect the alignment of the tires. It only centers the steering wheel).  Jeep TJs and the newer JKs  have a solid front axle therefore, you can only set the TOTAL toe. Both steering knuckles are connected making it impossible to adjust individual toe due to the fact that there is not a separate tie rod on each side of the steering gear.

A stock Jeep's solid axle offers rugged simplicity compared to IFS (Independent Front Suspensions).  It is the Wrangler's solid axles, coil-link suspension and steel components that also make it the most popular SUV for customization. As a result, alignment on a jeep can be extremely simple with very few adjustments necessary or it can be much more involved depending on the aftermarket components that have been installed.

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