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Discussion Starter #1 (Edited)
This isn't really a sales thread. I just wanted to post information about a question I get asked multiple times a day which is "What size swaybars should I buy?" That said, when you are ready to buy swaybars Cygnus Performance can give you the best price and fast, free shipping. We will beat any price and we stock every brand worth buying. I'll be happy to personally help you with technical questions before and after the sale. You get the best of both worlds with us. Real tech support, quick shipping and the lowest prices on the net. It's a combination you won't find anywhere else!


Swaybars & Endlinks

What are swaybars and why do you want to upgrade them?
Stiffer aftermarket swaybars are very beneficial to the handling of WRXs and STis. Upgraded swaybars are the best suspension modification you can make to these cars for the money. Like most cars, STis and WRXs come from the factory with a relatively soft suspension set up that is prone to understeer. This leaves a lot of room for improvement. If you are a performance minded driver who wants to get the best handling out of your car swaybars are a great place to start. A swaybar itself is a very simple part, but figuring out what type and size to buy is not so simple. There is no easy answer here, but in this post I hope to guide you in the right direction.

The purpose of a swaybar is to increase the suspension's roll stiffness. The stiffer the swaybar, the more resistant to body roll it becomes. This means that with stiffer swaybars your car will be flatter through corners, and your car will have more precise handling. Two of the other main benefits of upgraded swaybars are being able to fine tune your suspension to reduce understeer, and being able to increase overall grip though retaining more negative camber. Retaining more front negative camber (reducing dynamic alignment change) is particularly beneficial on cars like the WRX and STi because they use MacPherson strut front suspension (as apposed to double wishbone suspension). Double wishbone suspension is usually designed with a shorter upper A arm which allows greater dynamic negative camber gain as the suspension jounces than is possible with MacPherson struts. With MacPherson struts the fixed upper mounting position of the strut limits dynamic negative camber gain and actually causes positive camber gain once the suspension compresses past a certain point. During hard cornering if the front outside tire (the one with the majority of the weight on it) does not have enough negative camber the weight shifts to the outside edge of this tire. This results in much less traction than you would have if weight were distributed evenly across the width of the tire. For this reason cars that use MacPherson strut suspension will greatly benefit from reduced body roll and stiffer suspension. So to sum it up, a stiffer swaybar will help prevent dynamic positive camber gain for better grip, help keep the car flatter for better handling and help you tune your suspension to make your car feel more neutral.

Swaybar Sizes
I am often asked, "what size swaybar is best?" There is no single answer to this question. The answer will depend on many factors including what you use your car for, what other mods you have (if any), what your driving style is and what surface you'll be primarily driving on. Some people assume bigger (and more expensive) is always better. This is an incorrect assumption. If stiffer were always better the cars with the highest limits would have no suspension at all. Going with bars that are too large can be counterproductive. If a swaybar is too stiff it will not allow the suspension to properly do its job. For example, going with a 29mm front bar on a GD STi driven on a street with less than a perfect surface will cause the front tires to skip across uneven pavement resulting in less traction and poor handling. A 27mm rear bar on the same car may cause the rear inside tire to lift and will probably induce a lot of oversteer without the proper surface, tires and supporting suspension mods. These bars have their place, but for a car driven on everyday roads they are probably overkill. On the other side of the spectrum a bar that is too soft will not have enough benefit. The car will still have excessive body roll and you may not get the results you are looking for. Also keep in mind that if you have aftermarket springs or coilovers this will affect the size bars you'll need. Stiff coilovers will require a softer swaybar since they too resist body roll.

One nice thing about stiffer swaybars is the majority of the time they won't give you any increased noise, harshness or vibration. The only time when added harshness will be apparent is when you are driving on an uneven road where you are hitting bumps that cause the left and right wheels to move independently. If you drive mainly on well paved roads chances are the only time you'll notice your upgraded swaybars will be when you are going around a corner. If you frequently drive on rough, uneven roads it is important to keep in mind that stiffer swaybars will mean added harshness. This doesn't mean that you shouldn't upgrade your swaybars. It just means that you may want to go with a smaller bar than you would otherwise.

The 2002-2007 WRX and 2004-2007 STi share the same chassis and will respond similarly to the same combinations of swaybars. The same is true for the 2008+ WRX & STi. An important thing to note is that comparing the size of a 08+ swaybar to an 02-07 swaybar is not an apples to apples comparison. A smaller diameter 08+ bar will be equivalent to a larger diameter 02-07 bar. The 08+ 20mm bars are roughly equivalent to the 02-07 22mm bars, the 08+ 22mm bars are roughly equivalent to the 02-07 24mm bars and the 08+ 24mm bars are roughly equivalent to the 02-07 27mm bars. Lets look at some popular combinations of swaybars for these cars going from the softest to stiffest combination. It will be impossible to address all of the possible scenarios here, so if you have any specific questions feel free to give us a call or send us an email.

1) 22mm front & rear 02-07
This combo doesn't apply to the 08+ cars since Whiteline doesn't make a 20mm front bar for these cars. This is a very mild combo, but it is still a great improvement over stock. This is perfect for someone who drives on bumpy roads and doesn't want to deal with much increased harshness.

2) 22mm front / 20mm rear 08+ or 24mm front / 22mm rear 02-07
This combination is going to work well on street driven cars. It is conservative enough that it will be comfortable on almost any surface, but it still adds enough stiffness that handling will be greatly improved. The fact that the front bar is slightly larger than the rear bar will keep the car's natural tendency to understeer more than equal sized bars would. This is a good combo for someone who wants stiffer swaybars, but is worried about added harshness or going too extreme.

3) 22mm front / 24mm rear 02-07
Here is another combo that only applies to 02-07 cars. It may seem like an odd combination, but it is a combination that has been proven in street tire autocross. I'd only recommend a combination like this for cars that are using stiff coilovers. The rear bar will help make the car rotate while the soft front bar will work in conjunction with stiffer springs to provide the best overall grip possible. This is an ideal setup for the intricate low speed turns in autocross.

4) 22mm front & rear 08+ or 24mm front & rear 02-07
This is my personal choice for the street and street tire autocross. The equal sized rear bar gives the car a more neutral feel. It really does a lot to counteract the car's tendency to understeer. I use this combination on my daily driver and with Whiteline adjustable swaybars it can be set up to perform well on the street, track and autocross course.

5) 24mm front / 20mm rear 08+ or 27mm front / 22mm rear 02-07
The large front bar will provide a great turn in feel with this combo while the small rear bar will keep the car from oversteering much. If you want to keep all four wheels on the ground and have a solid turn in feel this may be a combo to consider. To me this isn’t a very neutral feeling combo. When I drove a car with this combination it understeered quote a bit.

6) 24mm front / 22mm rear 08+ or 27mm front / 24mm rear 02-07
This is another popular combination... Probably just as popular as combination #4. The stiffer front bar will give the car an improved turn in feel over combination #4. I find that this combination doesn't feel as neutral on street tires as combination #4. To me it feels like it gives you a flatter, better turn in feel at the expense of over all grip. If you are on a smooth track with grippy tires this is a different story. This combo is perfect for someone who does track days or time attacks. It is also the preference of many for daily driving. It does give more noticeably better handling than combo #4 for daily driving. It just doesn't suite my personal driving style as well as #4 does. National autocross champions have also confirmed that a bar this large in street tire autocross tends to make the car understeer. The fastest street tire autocross STis in the country for the past few years have used very soft front bars in combination with very stiff coilovers.

7) 24mm front & rear 08+ or 27mm front & rear 02-07
This combo is extreme. This rear bar will likely lift the rear inside tire when you go around corners fast. It is really only suited for cars racing on a smooth surface. If you have a dedicated racecar on race tires this might be the perfect combination for you. I don't typically recommend it for daily drivers though.

Whatever combination you decide to go with remember to drive conservatively and not push the limits until you become accustomed to your car's new handling characteristics. Changing swaybar sizes can dramatically affect the way your car handles at the limit.

Adjustable vs. Fixed
Whiteline swaybars are available in both adjustable and non-adjustable (fixed) varieties. An adjustable swaybar allows you to adjust the stiffness of the bar. This is accomplished by multiple mounting holes in the end of the swaybar (as apposed to a single mounting hole with a fixed bar). A rear adjustable bar will have 3 possible mounting holes on each end of the bar. Bolting the endlink to the middle holes will give you the equivalent stiffness of the actual diameter of the bar ie a 24mm bar will act as a 24mm bar. Bolting the endlinks to the inner holes will make the bar effectively shorter which makes it effectively stiffer. The opposite happens when you bolt the endlink to the outer holes. The bar becomes effectively longer and therefore effectively softer. I use the word "effectively" because the actual length and stiffness of the bar does not change. The only thing that is changing is the way that the bar is linked to the suspension. Each increment of adjustment is equivalent to approximately 2mm in bar thickness. A 24mm rear bar could act as a 24mm bar when set to the middle setting or a 26mm bar when set to stiff or a 22mm bar when set to soft. Front adjustable bars only have 2 adjustment holes and can only be adjusted stiffer.

The only real drawback of an adjustable bar is the slightly higher cost, but when you compare this to the cost of replacing an entire bar if you want to change size it is definitely worth while. When you install your new swaybars on your car and feel what they do you might find you want to stiffen or soften one or both bars. With adjustable bars you have that option. If you only have the budget to get one of them adjustable I'd recommend the rear for two reasons. 1) It gives you more range of adjustment than the front. 2) Being able to adjust the rear bar is more critical when it comes to the overall neutrality of the car. If you want to make the car understeer or oversteer more you will get more obvious results from changing the settings of the rear bar.

Swaybar Brands
In order to offer a wide variety to our customers we sell several brands of swaybars. While they all basically do the same job, my personal favorite is Whiteline. Whiteline has been making swaybars longer than the competition has, and Whiteline swaybars and endlinks are proven on the track and on thousands of cars throughout the world. They make some of the most copied parts in the industry, and in my opinion they are the most innovative suspension brand for Subarus. They offer excellent fitment and come in a wide variety of sizes. One thing I really like about these bars is the fact that they are forged from a single piece of Australian spring steel. This sets them apart from some of the competition who use welded on plates for their swaybar ends and/or use inferior steel. Again, this is just my personal opinion. There are plenty of reputable companies who make quality swaybars. Whiteline is just my favorite.

Endlinks are what connect the swaybar to the rest of the suspension. Without endlinks your swaybars would just hang and do nothing. They are a vital part that should not be overlooked. You can use your factory endlinks with aftermarket swaybars, but this doesn't mean you should. You have to remember these aftermarket swaybars are much stiffer than factory swaybars. The factory endlinks were only designed to cope with the stress of factory diameter swaybars. Depending on the year of your car aftermarket swaybars can cause the stock endlinks to flip and in some cases even break, but this is not the main reason I recommend upgrading endlinks. Factory endlinks are soft and don't give you the full advantage of your stiffer swaybars. Aftermarket endlinks will give your new swaybars a more solid connection to the rest of the suspension which means you'll get more benefit out of them.

Types of Endlinks

We offer several brands and styles of endlinks. I've sold a whole lot of endlinks and there have been happy customers with every brand and style we sell. Endlinks are a part that can be designed and built in very different ways each having its own drawbacks and advantages. Up until recently the two most popular styles were spherical bearing and urethane bushing endlinks. Both of these designs have issues. Spherical bearing endlinks are known to make noise in some cases. This is usually because dirt has gotten into the bearing. Urethane bushing endlinks have also been known to make noise in some cases. If a bolt doesn't pass through them at a 90 degree angle it puts stress on everything. Other types of endlinks allow free movement, but urethane endlinks resist anything that is not 90 degrees. In many cases this is not severe enough to cause binding and noise problems, but it is definitely a possibility. The other problem with urethane bushings is they are soft. They flex around quite a bit which puts a buffer between the swaybar and lower control arm. They don 't allow the swaybar to do its job as quickly or effectively, so they don’t perform as well.

The new style I have been running and recommending is called a ball link. Whiteline started offering sealed ball link endlinks in 2010. This style of endlink brings together the best of both worlds. They perform significantly better than urethane bushing endlinks since they don't use spongy urethane bushings. They also fit better than urethane bushing endlinks since they allow free movement, but unlike spherical bearing endlinks they don't make noise. They cost a little more than urethane endlinks, but the difference in fit/performance is well worth the price.

Heavy Duty Rear Mounts / Braces
Whiteline makes heavy duty rear mounts for the 02-07 WRX & STi and rear swaybar mount braces for the 08+ WRX & STi. These kits both accomplish the same thing. They strengthen the factory mounting points for the rear swaybar. This helps prevent any flex which helps you get the most out of your rear swaybar. It also helps prevent any kind of breakage or failure. Your factory mounting points were only designed to cope with the stress of your factory diameter swaybar. When you add an aftermarket swaybar you put A LOT more stress on these mounts. These kits are not absolutely needed, but they are something I highly recommend. The rear braces are included with all Whiteline adjustable 08+ swaybars, but you can buy them for any swaybar.

If you have any questions about anything feel free to contact me.

Phone: (321) 600-0889
Fax: (321) 600-9415
AIM: CygnusPerf
Yahoo Messenger: CygnusPerf

4,957 Posts
Discussion Starter #3
This should be stickied in GD/GR Suspension forum!

Thanks! That would be nice, but I would be very surprised if it happened :lol: If any of the mods agree I'd be happy to edit it a little and remove the direct links to my site. In the tech forums more people would see it for sure. Anyway, thanks for reading glad you found it helpful.

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