08-22 WRX and STi Rear Camber and Toe Correction
– Introduction –
For many people this is going to be the second most important suspension modification after a good set of coilovers and the most important supporting mod to go with their new coilover set. I know I’ve typed up a couple of replies to questions about this in the group, but I wanted to make an official comprehensive post. In this post I will cover both why/when adding aftermarket adjustment is recommended and the brands and components that I personally recommend using. Although they are not on our website yet I have also decided to start selling these components again after a long hiatus.
In the interest of keeping this post more concise I am going to assume that readers understand what camber and toe are. If you’re not sure what these terms mean an internet search for a quick illustration would be the best way of understanding it.
– When is Adding Rear Alignment Adjustment Important? –
Off the showroom floor these cars do not have rear camber adjustment. It’s important to note that this does not necessarily mean your rear camber values are very good off the showroom floor. Oftentimes these cars have pretty bad camber numbers even at stock ride height. Sometimes left and right camber are very far from symmetrical. Over the years I’ve sold many sets of rear lower control arms to customers who need alignment correction even though they have not changed ride height. When you start changing ride height matters only get worse. You pick up a pretty significant amount of static negative camber when you lower these cars.
When your rear camber values are too high/too low, not symmetrical or both you can expect accelerated tire wear, less than ideal handling and sometimes the car will even pull to the side on the highway. Aside from improving handling, adding adjustment if you need it typically will pay for itself pretty quickly by extending the life of your tires.
Adding rear camber adjustment is always a good thing provided that you are adding it with high quality components. Without it the rear camber values are pretty much guaranteed not to be perfect. The importance of aftermarket alignment adjustment for your car is going to come down to four main variables which are how far off your alignment was when your car was new, how much it has changed since, how much lower or higher than stock you’re adjusting ride height by and how you want to set alignment. Obviously there is really no way of definitively knowing how critical adding rear camber adjustment is until you get the car on the alignment rack, but virtually every single person who owns one of these cars will benefit from having adjustment at least to some degree.
– Ways of Adding Rear Camber Adjustment –
Unlike with the front of the car you cannot adjust rear camber via camber plate. Camber plates only work on MacPherson struts. We do offer rear camber plates on the older models that use MacPherson struts on all four corners, but because the rear is multilink on any 2008+ WRX or STi rear camber plates are not an option with any coilover set for these applications.
There are four main ways of adding rear camber adjustment. You can do it with adjustable rear lower control arms, adjustable rear upper control arms, eccentric upper control arm bushings or eccentric lower control arm bushings. In my opinion you can eliminate two of these options right off the bat because these bushing kits with offset tubes are more trouble than they are worth. They do cost a bit less than going with a full arm, but that is the one and only advantage. They have a very finite range typically only giving you about 0.75° of adjustment, they are finicky to adjust which makes getting the values you want and getting things symmetrical difficult, they use low quality urethane bushings that are a downgrade from the stock bushings and on top of all of that most alignment shops have no idea what to do with them and the ones who do typically charge you extra because of the difficulty of adjusting them which negates any advantage with price. They are a waste of time – don’t buy them.
This leaves full upper control arms and full lower control arms as the two viable options of adding rear camber adjustment. For the vast majority of people rear lower control arms are going to be the way to go. They are more accessible and significantly easier to adjust. They offer more adjustment range, and there are a lot more options on the market. In rare instances adding an adjustable upper control arm in conjunction with an adjustable lower control arm can be helpful to have better control of offset, but this is not going to be necessary or beneficial for most people.
– Additional Rear Toe Adjustment –
These cars do have factory toe adjustment, but when you add rear camber adjustment this factory toe adjustment is often insufficient. It’s an eccentric bolt with a finite adjustment range that was not designed to compensate for camber adjustment. A turnbuckle toe arm is the best way of adding additional toe adjustment. It’s easy to adjust, and it has plenty of range no matter what you are doing. As with rear lower control arms there is no downside to adding this adjustment as long as you go with a high quality toe arm. I also like to remove the factory eccentric adjustment when turnbuckle toe arms are added since it becomes redundant. A straight bolt that eliminates it makes adjusting things less finicky and greatly reduces the chance of anything slipping.
– Rear Camber and Toe Values –
I wanted to add this section just so readers understand that I am deliberately omitting this information from this post. Recommended alignment values are a long discussion and highly dependent on individual uses. I will make a future post that comprehensively covers recommended alignment values for specific uses. In this post I will simply say that while adding adjustment is always beneficial it becomes highly recommended if you have less negative camber than -1 or more negative camber than -2 or if rear camber is different from left to right by more than half a degree.
I should also point out that alignment values on pre-2008 WRXs and STis are not an apples to apples comparison with the newer cars. Dynamic camber characteristics have to do with how camber changes as the suspension is compressed (eg when you are cornering). The dynamic camber characteristics with unequal length double wishbones is superior to MacPherson strut dynamic camber characteristics. Because of this you need less static negative camber (the camber value when the car is sitting on a flat surface) in the rear of the newer cars than you did with the older cars.
– The Brands I Recommend –
As with any suspension mod the quality of the components you buy is absolutely mission critical. Just as with coilovers when it comes to lower control arms and toe arms low quality overseas made options can be very problematic and a big downgrade from stock. If you go with high quality components adding alignment adjustment will not be the only benefit that you experience. You will also end up almost completely eliminating unwanted movement and play in these suspension components. Less unwanted movement and play and better articulation will greatly improve suspension function. You’ll be able to tell what the car is doing at the limit, and handling will be noticeably more precise and confidence inspiring.
Some of you have been following my suspension tech posts for a long time. I have been making them in places like Nasioc since 2006 and for more than a decade here on Facebook. My opinions and recommendations when it comes to manufacturers are always evolving. As some of you have seen I am not afraid to contradict myself or change my recommendation if a product changes or if my own experiences and research provide new information. I am not married to any of these third-party manufacturers or suppliers. For the most part I can sell whatever I like which means that I sell what I recommend rather than the other way around. My sole interest is getting you guys the best possible results and value for your money.
With all of that said my recommendations on brands when it comes to these components have changed several times over the years, and recently they have changed again. For many years now my go-to recommendations for aftermarket control arms and toe arms have been Cusco if you’re not worried about budget and SPC if you want something cost-effective. Although these are no longer my top recommendations they are still a reasonable way to go and better than the majority of the competition.
Although SPC is still probably the best cost-effective option it’s a slotted sliding style rather than a turnbuckle style. This makes adjustment more difficult, and it significantly reduces adjustment range. A turnbuckle is a better solution. The problem with a turnbuckle is a good turnbuckle is not cheap, so if you want to spend $400 or less you don’t want a turnbuckle. If you have the budget for something high quality ($600+) a turnbuckle is always the way to go. Adjustment is easier, and you have far more of it.
I currently have three Subarus in my fleet which are a 2013 STi hatch, a 2017 manual transmission Forester and a 2020 Outback Touring XT. For years now I have been running SPL on the STi and Cusco on the Forester. These are my two favorite turnbuckle adjustable lower control arms. Cusco was my top recommendation simply because it has a sealed heim joint rather than an open heim joint like most of the other options. After seeing cheap heim joints make noise or fail completely I felt that recommending something that was sealed better served our customers who were daily driving. However, after many years of running these two control arm sets a recent incident made me rethink all of this. One of the Cusco heim joints failed. Upon closer inspection the seal was trapping moisture and dirt and doing more harm than good. I would guess that the seal probably did do its job properly for a couple seasons, but my American made SPL heim joints are still going strong. I do hit them with spray lithium once a year, but that’s not really a big deal.
The failed bearing alone is not what caused me to change my recommendation though. It was the solution to the failed bearing that was the bigger issue for me. Although I have not had to replace them, the high quality American made FK heim joints that SPL sources out of Connecticut only cost about $15 a piece to replace. They are very nice component that is Teflon lined and produces very little friction. The fact that you can get a high quality heim joint made in the United States for this price shows you how cheap these lower quality brands are being when they get something that probably costs less than $1 out of China. With Cusco it seems that you are looking at the typical JDM tax. These are $157.50 each to replace, and because they are made overseas having a quick replacement is not guaranteed. Admittedly I have no idea what it costs Cusco to produce one of these, but when I look at it next to the $15 SPL component that outlasted it I personally can’t figure out a good reason that it should cost 10 times the price.
Aside from my own personal experiences with longevity and ease of adjustment when compared to SPC and Cusco I like SPL because it’s CNC’d in the United States from 6061 billet rather than welded or stamped. They use a triple electroless nickel plated adjuster which has been totally bulletproof for me. They also give you multiple mounting point options for the rear shocks and end links which is nice.
They offer a turnbuckle toe arm that eliminates the redundant factory eccentric toe bolts which is always a good idea when you are adding a turnbuckle adjustable toe arm. As with the lower control arms these use components that are easily replaceable in the United States if you ever need anything which is a huge advantage over some of these other brands.
SPL is my top recommendation for both of these components. They also manufacture trailing arms, adjustable length end links and a roll center adjustment kit that is actually adjustable for different ride heights. The benefits of these other components is beyond the scope of this post, but I’m happy to help if anyone has any questions.
About a year or two ago we removed all of these supporting mods from our website. When it came to tech support I was spread too thin, and I wanted to make sure there were no compromises when it came to supporting our coilovers. Even if it costs me money I always want to run a business that I would personally be happy with purchasing something from which means a lifetime of real tech support before and after the sale. I decided that these supporting components are important enough that we really need to sell them with our coilovers. In the coming weeks we will be adding SPL back to our website (CygnusPerformance.com). In the meantime I’m happy to get anyone who is interested the best price on these components with free shipping and no sales tax to most destinations. Please feel free to PM me if I can help.
– Thank You –
If you found this technical post helpful please share it. You guys spreading the word is greatly helpful to me. It’s why I’m able to spend my time typing this stuff up rather than advertising. I will continue to do everything I can to get people in the Subaru community the best possible value and results with their suspension. Thanks for reading, and if you have any questions feel free to post them below or PM me 
Thanks,
Geoff