Perrin Sway Bar - 22mm, Rear Kit

04-07 STI, 04-08 Forester XT

Description:
KEEP THAT CAR FLAT IN THE TURNS!!

The only way to make your car turn, stop or go is if the entire available tire patch is hitting the surface at hand. The factory included what many regard to be a whimsical attempt to increase cornering with puny sway bars on the front and rear. PERRIN™ sees the need for far larger and stronger sway bars and now offers two choices for the rear end of your car.

For street enthusiasts that simply want to attack the drive to work with more gusto, the 22mm (7/8”) PERRIN swaybar kit is the ideal choice. While dedicated track hounds will delight in the increased snap now available from our 25mm (1”) offering. Each size and each end also incorporates 2 adjustment holes to help you custom tailor your suspension to your specific needs and driving habits. Made from solid steel and heavily powder coated to prevent the rigors of salty roads that wreck havoc with less worthy products. All kits include polyurethane pocketed bushings to prevent tedious re-greasing and all necessary hardware for a clean, and painless installation.

Stout Mounts
All PERRIN swaybar kits include the Stout-Mount™ system. This is another factory flaw. The Stout Mounts area connection between the unibody and the rear sway bar. Subaru chose to use cheap stamped steel. While great to keep costs down it certainly won’t help you go around that next bend in anything resembling a spirited fashion. Impreza owners can take full advantage of the 6061billet aluminum mounts. These mounts are overbuilt to handle the added stiffness of upgraded swaybars. You will never have to worry about these failing

Endlinks
Also any rear sway bar and swaybar kit can be purchased with or with out our endlinks. PERRIN™ recommends the use of upgraded endlinks to take full advantage of any swaybar upgrade. Endlinks are the connection between the swaybar and the suspension arms. Some Subaru models use plastic (yes plastic) to make this connection, where as the Legacy uses a solid type connection. So why replace it? The OEM steel endlinks are designed to hold up under the stresses of the OEM bar, not upgraded swaybars. Replacing these with PERRIN solid endlinks will add to the durability and save you some weight at the same time. PERRIN™ Endlinks are made from 6061 billet aluminum and use spherical bearings. This provides a solid non-flexible connection from the sway bar to the control arms.

How does a sway bar work?
First understand that a tire has flat contact patch. If the contact patch is not parallel to the ground, the contact patch gets smaller. In turn traction is lost. As the car makes its way through a turn, the weight of the car, causes the car to lean. As the car leans, the design of the suspension geometry makes the tires contact patch become unparallel to the ground. In turn loosing traction.

Suspension designers used camber to help counteract this, along with unequal control arms. But a large part of keeping the tire parallel to the ground during cornering is controlling how much the car leans. This is where sway bars come into play. During cornering the sway bar acts to keep the chassis from leaning. In turn this helps keep the tires parallel to the ground. Stiffening up the springs on the car does the same thing, but in turn makes the ride much harsher. Sway bars are like stiff springs but only become effective while cornering.

Swaybars connect both left and right control arms with a torsion bar. As the control arms move up and down together, the bar moves with them. During this state the sway bar has no effect. Only when the control arms move in opposite directions does the sway bar come into play. During a corner, the outside arm moves up and the inside arm moves down, in turn causing the sway bar to twist. The opposing directions of the arms are counteracted by the sway bar and the sway bar tries to keep the arms from moving in opposite directions. In turn keeps the car from leaning less, and give you more traction!

Why do I want this?
That is easy to keep the contact patch as flat to the ground as possible! Both front and rear sway bars do different things to cars. Both front and rear sway bars increase traction to the outside tire (the one with the most load), but a balance of front to rear can change how the car handles.

All cars are designed to have a slight amount of understeer. This is done for safety reasons. Understeer is the effect when you go into a corner, and your turn the wheel, but the car goes straight. This is also known as pushing or plowing. In contrast oversteer is when you go into a corner, and the car turns more than you steer. This is also described as the rear end feeling like it is sliding out slightly. Too much oversteer and you will spin out in a corner. Too much understeer and the car will not turn through the corner, and go straight off the road.

Generally people prefer neutral handling or a slight amount of oversteer. With the choices in bar sizes and endlink settings, anyone can find the perfect match to their driving style.

Hollow vs. Solid
Given both are designed to produce the same rate or stiffness, they both do the same job. But in order to get a hollow bar to produce the same rate, a very large diameter is needed. And for those wanting something with a high rate or stiffness, you won’t be able to find this in a hollow bar. Another benefit hollow bar makers try to sell is the weight. The difference in weight is very very small. To give an example, a rear WRX PERRIN sway bar weighs 10.8lbs. Even if you remove the entire bar, the savings isn’t much. If weight is that critical, you can always remove your spare and save more weight. All PERRIN sway bars are made with solid 4140 Steel bar. This provides the best in both stiffness and durability, and creates a bar that will last forever.

Bushings
All PERRIN swaybars use custom made polyurethane bushings. We went direct to the experts on this and that is why you will find 100% genuine Energy Suspension bushings. All of our bushings use a high durometer (really stiff) urethane to ensure the most from your sway bar. A common problem with urethane bushings is the squeak really bad when the grease dries up. PERRIN performance has custom internal spiral cores for each bushing. This allows the grease to stay in the bushings, and constantly lube the sway bar. In turn this makes for longer service intervals compared to traditional smooth bushings. This is a small detail that other sway bar manufactures don’t offer!

OEM Mounts
The OEM swaybars mounts produced between 2002-2004 were a single piecestamping. These are known to fail under harsh conditions when using theOEM bar, let alone bigger stronger aftermarket bars. Mounts producedlater than this date are made of 2 stamped pieces, which don't failwhen using the stock swaybars, but with aftermarket bars forget it! These mounts are known to bend and fail when aftermarket bars areinstalled. The answer to this problem and concern is......

Stount Mounts
The PERRIN stout mounts are over built to keep your concerns atbay. The mount starts life as a block of aluminum and are machineddown to .8lbs of art. While these mounts are over built to handlelarger swaybars, we were still concered with keeping the weight down. The mounts are strong enough to with stand the forces of swaybars 10times the rate of the OEM bar. Nearly all swaybars will fit the PERRINStout mounts. The Stout mounts will fit with 17mm, 19mm, 22mm, 25mm,and some 27mm bars. The most popular size bushings are included tosuite most peoples needs. Call for further details about bushings.

Includes:
PERRIN 22mm or 25mm Rear Swaybar
PERRIN Stout Mounts
Energy Suspension Bushings and grease