Official Suspension FAQ - Swaybars - Struts/Springs - Coilovers - Alignment
 

Under Construction with a new revised version

Strut / Spring FAQ

This FAQ has been written by fwa2500. The original post can be found HERE

I am tired of the same questions being asked over and over again, so here is a FAQ that I have put together with the help of Reuben.

Will STi struts and springs work on my car?

Yes, but only '04 STi struts will be a direct fit because in '05 the hubs were changed from 5x100 (which is what your car is) to 5x114.5. '05-07 STi springs will work too, but also require the '04-07 top-hats. Additionally, any '02-07 WRX set-up will work since the WRX never changed away from the 5x100 hub.

I found some '05 STi struts and springs, can I use those?

The springs, yes, but not the struts for the reason mentioned above.

How much lower will STi struts and springs make my car?

Approximately 1 inch.

What about WRX struts and springs?

As stated above, yes they will fit. Any '02-07 WRX strut, spring and top-hat combo will work on our cars. These will only lower half an inch at most with the stock WRX springs.

Can I use just STi springs?

Yes, but you will need the 04-07 rear top-hats if you are using 04-07 springs. If you are using JDM springs meant for a bugeye (GDA) you should be able to use your stock top-hats.

Isn't STi stuff really expensive?

It can be, but for a complete set of '04 STi suspension you are looking at about $300-400, which is a pretty good deal when compared to our stock set-ups.

Would 3rd or 4th gen stuff work?

Unfortunately, no. Both have a completely different rear suspension set-up.

I want my car lower, what is the easiest way to do it?

Get a good set of aftermarket struts or springs, or even both. DO NOT cut your stock springs, not only does this decrease your handling performance but it can be very dangerous.

I want my car slammed and heard S-Techs are the way to go.

No. Just no. You might as well cut your stock springs, just get a good set of performance springs and enjoy. You might not be quite as low, but you and your car will thank me. Please see THIS THREAD on NASIOC for more info.

I've heard wagon and sedan rear struts are different, won't you get 'ass sag' with sedan struts in a wagon?

Generally it's chassis related. In most cases, second gen. Impreza (bugeye-hawkeye) suspension works just fine in our second gen. Legacy wagons and sedans. The exceptions being the 05-07 STi struts which don't work due to the different hub. GC/GF (first gen. Impreza) stuff also works in Gen 2 Legacy's, but GC/GF Impreza rear shocks and springs are shorter, and so you get the 'ass sag', regardless if it's from a wagon or a sedan.

Is it hard to swap struts over?

If you've worked on cars before and generally know you way around, no, it's an easy job. I recommend having a friend help out when installing the struts, it makes things so much easier. Keep in mind that you must get an alignment done once finished.

Ok, I installed some WRX suspension and now my wagon has a saggy butt. How do I correct this?

Spacers. Putting spacers in between the top hats and the top strut mounts on the car will help correct the sag.

That is all good and all, but let's say I want to **gasp** raise my car.

In that case, your best bet is swapping on BD/BG Outback struts and springs or second generation Forester struts and springs.

All that performance stuff is nice, but what about just replacing worn out OEM struts with stock-spec struts?

For that I would recommend KYB GR-2 struts, they are nicely priced and are excellent quality all around. Another option would be Monroe, they are also good stock replacements.

While I have the car in the air, what else can I do to make my car handle better?

One simple thing you can do is install camber bolts. These will give you more available camber (can produce both positive or negative camber) to fine-tune your alignment.

What about swaybars and endlinks?

Good question, please check out Zeus Marine's repost of Jamal's excellent swaybar FAQ HERE.

What are you running on your car?

I currently have '04 STi struts with '05 STi springs, a 22mm adjustable Whiteline rear sway bar, Tribeca 25mm front sway bar, Kartboy solid front and rear endlinks, Ingalls camber bolts on all four corners and a slightly aggressive alignment (-2.3 degrees front camber with zero toe and -1.4 degrees rear camber also with zero toe).

More will be added as is needed. I hope this helps some ;)

Swaybar FAQ

This FAQ has been written by Jamal

I've noticed a lot of swaybar related threads in the short time I've been around here, and I also have noticed a lot of misinformation and contradictory advice. So I thought I'd polish up my old legacycentral FAQ and post it over here.

I'd like to start by talking about how our cars handle and what happens to our tires and suspension when we go around corners.

From a flat out, on-road performance standpoint, a subaru starts out at somewhat of a disadvantage. Off the showroom, these cars are set up to understeer, and understeer some more. And then keep on understeering. Understeer is when, in a corner, the front tires break traction and begin to slide.

One reason for this is the AWD. You have four wheels powering the car, and give the fronts the additional task of steering. That right off the bat means that while accelerating and turning, the front tires will lose traction first.

Another problem is the weight distribution. On top of asking the front tires to both accelerate the vehicle and steer, you've gone and put more weight on them. Guess where that leads.

Now we come to the alignment and suspension geometry. When the suspension moves, the alignment changes. This can be a huge advantage, or a big problem, depending on the suspension geometry. In our case, it's a big problem. A tire creates the most grip when the entire tread is in contact with the road. When you go around a corner with the stock car, the car leans over, the tire leans over, and you end up doing most of the cornering with the outside edge of the tire and sidewall. That's not good for grip. Additionally, when the suspension compresses past a certain point the tire will camber out, which makes the problem even worse.

On top of these inherent handling disadvantages, the cars are setup to push at the limit. This is because it's generally safer to go off the road straight than it is backwards/sideways, and inexperienced drivers tend to have trouble dealing with oversteer. There's also something called lift-throttle oversteer, and it's a common cause for crashed wrxes.

Okay so what do I do about it, and what does this have to do with swaybars?

One part of the solution is the alignment. Start with the tire leaned in (negative camber), and when the car rolls the tire ends up with more tread contact. More negative camber in the front means more cornering grip in the front and less understeer. I daily drive with over -2 degrees of camber and have not noticed any additional tire wear. However, it is important to have the toe set to 0 or slightly in, rotate tires frequently, and make sure all of your suspension and steering components are in good condition.

The other part is to not let the car roll as much. Reduce roll, and you reduce how far the tire leans over, and you improve grip. That's where stiffer suspension and swaybars come in. Since this is a thread about swaybars, I'll start talking about swaybars now.

What is a swaybar?

A swaybar (aka anti-swaybar, anti-roll bar etc), is a bar that connects the left and right sides of the suspension. It twists to resist the suspension on one side of the car from being at a different height than the other side. Swaybars exist to add roll stiffness without adding ride stiffness. On a stock Subaru, it's been calculated that the swaybars do about twice as much to resist roll as the springs.

What is roll stiffness?

Roll stiffness is a car's resistance to body roll. Body roll is caused by cornering force. Cornering causes a lateral acceleration, and that force acts through the center of gravity about the roll center (that's a hint at why roll center height is important). Both the springs and the swaybars resist this rolling force.

Why is roll stiffness important?

A car will more roll stiffness will have less body roll and the suspension will load and react more quickly. That is good for two reasons:

1) the tires stay flatter on the road and create more grip
2) the car is more responsive and changes direction more quickly

Great... What does that mean for me?

Swaybars let you add roll stiffness efficiently and also adjust the front to rear handling balance of the car.

A very important rule of suspension tuning is that adding roll stiffness to one end reduces the grip.

The front and rear of the car each resist body roll. Given a constant cornering force, that resistance will be proportional to the roll stiffness on each end, so the end of the car with more roll stiffness will resist more roll.

Doing more to resist roll means that more weight is transferred.

More weight transfer means less proportional grip.

So a car that understeers probably has too much front weight transfer, and not enough in the rear. Adding rear roll stiffness (or taking it away from the front), will increase weight transfer in the rear, and reduce rear grip relative to the front, making for a more neutral handling car.

So then I should buy a rear swaybar?

Yes, probably. To reduce understeer, you need more rear roll stiffness. But to improve grip, you need less body roll. Can you see the conflict here?

A big front swaybar drastically reduces roll, and keeps the tires in better contact with the road. That improves grip. It also increases the weight transfer on the front end. That reduces grip. The interesting thing is that our cars roll so much and gain so little camber under compression that a big front swaybar can, in some cases, reduce understeer.

What it comes down to is that the car really doesn't have even close to enough roll stiffness to keep the tires in good contact with the road. If you want to make the car handle well, it's most important to add more overall roll stiffness. Just a big rear swaybar takes away rear grip, which will improve the balance, but it doesn't help with the severe lack of grip that exists in the front. Just a big front bar will help with the grip lost by the front due to body roll, but you end up with a car with a very front-biased roll stiffness.

In some auto-x classes, only a front swaybar is allowed. If you're in this situation, get a massive front bar from addco or strano. Otherwise, it's ideal to add roll stiffness to both the front and rear ends of the car.

How big is too big?

Well, that depends on the intended use, the tires, and the rest of the suspension.

In theory you want the bars to be as small as possible to maintain suspension independence and keep damping properties as consistent as possible. In reality, or rather with the weight and suspension geometry of our cars, you need A LOT of swaybar to handle well on road. Honestly, more than is available for our cars. A good track setup for an impreza with sticky street tires generally involves about 450 lb/in springs and 27mm bars. With R-compounds more spring rate is required.

So, if you're looking for great on-road performance, bigger swaybars are very important, and for a Legacy, there isn't a readily available swaybar that I would consider too big. I have the 22mm front and rear adjustable whitelines to go with my sti struts and springs. I'm pretty happy with the setup, although I intend to buy stiffer springs and stickier tires.

One thing to keep in mind is that bigger swaybars add spring rate that the dampers have to deal with. So if you have 100k mile stock struts, I'd be wary of slapping on some big bars without at least throwing on a set of fresh KYBs.

Okay, well, I think I have a good start. I need to expand on the last few parts a little and update the next post for the newer Legacies.


Fitment:

We've all heard the term that Subarus are like lego and you can interchange many parts between models and years. This mostly holds true for swaybars but there are some exceptions:

Generation differences
In the front, all Legacy swaybars are the same from 90-04, with the only difference being turbo vs. non turbo. There are also two different bushing and mount types, but bars are the same.
The FRONT 05-09 swaybars are different and do not fit on other legacies (although they interchange with 08+ imprezas).
Rear swaybars for an 00-04 Legacy must be specific for that model.
Rear swaybars for an 05-09 Legacy must be specific for that model.
Front swaybars for a '10+ must be for that model.
Rear swaybars for a '10 Legacy are the same as 08+ imprezas and foresters.

Turbo and non-turbo front bars are different

Because of the crossmember and exhaust differences, turbo and non-turbo bars do not interchange.

Impreza rear bars don't fit any Legacies

Our Legacies have a little bump that sticks out of the spare tire well and interferes with Impreza rear swaybars. So while a Legacy bar will fit perfectly on an Impreza, things don't work the other way around. This also probably applies to Forester swaybars.

The new wider-tracked WRX and STi front bars don't fit

The 02-07 WRX sedan has a wider track and therefore different control arms and lateral links. This means that the front swaybar has to be wider. WRX Wagon and non-turbo front bars DO fit on any 90-04 Legacy, following that you are not trying to mix turbo and non-turbo bars. Sti rear swaybars are also wider.

90-91 and 92-99 rear swaybars are different.

The 90-91 uses a droplink setup that goes into a hole in the rear trailing arm. 92-94 uses the C-links that are found on most newer Subarus. Swaybars might be interchangeable. More details of the differences can be found here:
http://bbs.legacycentral.org/viewtopic.php?t=34005

Some legacies do not have rear swaybars

None of the 92-94 L models came with a rear swaybar. I don't think Brightons or some L models did either after 95. Adding one is a really good idea. To do so you need mounting brackets, lateral links, and endlinks. More details here:
http://bbs.legacycentral.org/viewtopic.php?t=26464

Sizes

Okay finally we're here. Regardless of the car you have, there are different swaybars out there. Here's a list of sizes that came on different models of Subarus that will fit 1st and 2nd gen Legacies.
These may not all be correct and it would be great if people could confirm the stock sizes

Turbo Front

Legacy
91-94: 18mm
GC WRX/STi: ?
02-07 WRX wagon: 20mm

Non-turbo Front

Legacy

90-94: 18mm (19mm air suspension?)
95-99 2.2: 19mm
96-99 2.5: 20mm

Impreza

93-01 L sedan: 18mm
93-97 Wagon: 19mm
93-96 LS: 19mm
OBS: 19mm
98-01 RS: 19mm
02-07 RS/TS/i: 20mm

Tribeca: 25mm

Rear

Legacy

90-92 non-turbo sedan: 16mm
90-92 non-turbo wagon: 17mm?
92-94 L: n/a
92-94 LS, LSi sedan: 16mm
92-94 LS, LSi wagon: 17mm?
94 Ti/GT/Mi: 17mm?
91-94 turbo: 18mm
95 (all): 15mm
96-99 2.2: 15mm
96-99 2.5: 16mm
95-99 outback: 18mm
Impreza and 00+ Legacy bars do not fit.

Whiteline Aftermarket

Turbo front

BSF18 - 20mm
BSF18X - 22mm
BSF20Z - 22mm adjustable (22-21)
BSF20X - 24mm
BSF20XZ - 24mm adjustable (24-23)
BSF20XXZ - 27mm adjustable (27-26)

Non-turbo front

BSF19 - 20mm
BSF19X - 22mm
BSF19XZ - 22mm adjustable

rear 90-91

BSR17 - 18mm
BSR17X - 20mm
BSR17XZ - 20mm adjustable

rear 92-99

BSR19 - 18mm
BSR19X - 20mm
BSR19XZ - 20mm adjustable
BSR19XXZ- 22mm adjustable

Other Aftermarket

Rallitek - 22mm non-turbo front bar
Addco - 1" F, 7/8" R
others?

Bushings, mounts, and endlinks

The bushings in the endlinks and on the swaybars are made of rubber and they flex. That reduces the effectiveness of the swaybar. Replacing them with urethane or spherical endlinks is generally a good idea and really improves responsiveness because the bushings and endlinks aren't flexing as much before the swaybar loads, and will cause the swaybar to load more quickly. The only thing you need to keep in mind is that urethane bushings need to be well greased or they will bind and pop and possible tear apart. Whiteline makes urethane bushings in most sizes. Spherical bearings will also wear and eventually start to make noise.

The rear swaybar mounts have been known to break with larger swaybars. Whiteline, Perrin, and Cobb all have stronger mounting brackets available. The cheapest replacement option, however, are the 04-07 Impreza mounts, which are reinforced. They use a new bushing, and that Whiteline part number is W0406-[mm].

As far as endlinks go I'm partial to Kartboy and Whiteline but pretty much anything will work.


^Courtesy of Jamal for all his hard work documenting his experiments ^

COILOVER FAQ


What are coilovers?

Coilovers are an alternative to your stock McPherson strut setup. There are advantages and disadvantages of using a coilover system. If you're even reading this thread, you most likely want better handling out of your Legacy. Read on and I'll explain in more detail.

What are some of the benifits of coilovers?

Just to name a few....Coilovers can allow more alignment custimization, lower ride height, stiffer suspension, less weight, better spring rates, adjustable rebound and dampening, etc.

Sounds like coilovers are the way to go! What is the down side?

The biggest factor is cost. There are some "affordable" coilover kits that start at around $450. The quality of these kits are questionable. A "good" set of coilovers will cost you well over $1000. The other downside to them is ride quality. To many, coilovers on a daily driver car are a little too rough. Most coilovers (even on the softest setting) are considerable stiffer then stock Legacy suspension....Therefor your ride will be much rougher.

I just want to slam my car, and I've heard that coilovers are the way to go!

If you want to lower your car more then lowering springs will allow you too, then coilovers are your only other option. If lowering is all you car about, then I suggest a cheap set of generic coilovers.

I don't need coilovers to slam my car! I can just cut the springs! You're an idiot!

Go right ahead and cut your springs. I won't stop you. I'll just point and laugh at you when I'm riding in traffic behind you and I see your car bouncing around everywhere. As well, good luck with any kind of "aggressive" driving on cut springs.

Can you explain a little bit about the benefits of how a Legacy handles with coilovers?

My favorite thing about my coilovers is the fact that I can run excessive negative camber. I frequently go on mountain runs and track my car. Running about -3 degrees of negative camber helps my handling in corners A LOT. I wouldn't be able to do this with any kind of stock suspension. The camber plates that are on most coilovers allow up to -6 degress of camber. Your caster and toe angles are not affected by coilovers however.

Another big thing is body roll. I currently have D2 Racing coilovers. I have almost NO body roll (and I'm on stock sway bars too!)

When driving my Legacy compared to other Legacys that are on stock suspension, I feel MUCH more planted to the road. As weird as it may sound, I feel connected to the road...instead of just driving over the road.

So all this information is cool and everything....but I can't find coilovers that are made for my car!

You can use any coilovers that are made for 95 - 99 Legacy / Outback. As well, you can use any 2004 STI or 2002-2007 WRX coilovers. You will find the most options shopping for WRX coilovers. They are a direct bolt on mod.

So I bought WRX coilovers....but I cant clip my brake line now? What gives??!??

The WRX/STI uses a different brake line...and a different clip. You have two options to solve this problem.

Ghetto option #1

Zipties. Just ziptie your brake line to the coilover

Correct option #2

Swap brake lines. You can buy any 2004 STI or 02 - 07 WRX brake lines and clips to properly secure them. While you're out shopping for brake lines, I suggest picking up a set of stainless steel brake lines. They will help you maintain a nice pedal feel.

I want stance....yo

Then please go buy another car. Don't destroy a Subaru. Most Subaru enthusiast are function over form. You will find little to no help destroying a Subaru around here....or any other Subaru site that I know of. If you want "stance", then maybe you belong in a Honda.

Can you explain cambler plates?

Camber plates allow you to adjust camber from the top of the coilover, instead of using an essentric bolt in the steering knuckle. Using this method allows for much more adjustment in either direction, as well as an alignment that will not get "knocked out" as easy.

I just got my coilovers and I don't know what I should set them to? Can you tell me?

No I can't tell you. However, I can help you get started. Its best to set them in middle. If they are too soft, then you can adjust them a little to the firmer side. If they are too firm, then adjust them softer a bit. Its a trial and error thing that each person has to figure out on their own.

What are the available coilovers for the Legacy?

There are countless coilovers out there. I'll highlight a few of the major ones.

Raceland USA

These are "budget" coilovers. Quality is questionable and spring rates are unknown. Some people love these, and some people hate them. This would be a good option if all you car about is being lowered.

Rokkor

I personally believe that all of the generic coilovers on the market are made by the same people, just marketed under different names. All of the "budget" sets are pretty much the same.

Godspeed

Godspeed

I have no experience with these. I have read both good and bad reviews on them. It seems like these may be good for someone who wants a little bit of performance and a lower ride height.

http://www.wkionline.com/index.php?route=product/product&product_id=88

These are the "cheapest" coilovers that I would personally buy. They have great reviews and I have personally driven several cars with them. They seem to handle well, and the ride quality is not that bad.

http://www.sandrperformance.com/02-07-WRXSTi-BC-BR-Coilovers_p_182.html

These have EXCELLENT reviews. I have driven on BCs before and I love them. If you want something that will give your car a good look, and help it handle extremely well, these are for sure a viable option.

http://www.d2racing.com/content/products/coilovers

These are my personal favorite. D2R actually makes coilovers specific to the Legacy, but they are NOT cheap. My set was $2300, but was worth every penny. I have driven almost every kind of car on the road on every kind of suspension, and I still have yet to find a suspension system that performs like D2Rs coilovers.

ALIGNMENT FAQ


Camber

http://img.photobucket.com/albums/v2...ign/camber.jpg

Camber is the measurment of how much the top of the wheel is tilted in or away from the center of the vehicle. Most FWD or AWD cars run slight negative camber to help combat excessive understeer.

On most cars, running excessive negative camber will wear the inner edge of tires VERY fast. However, for some reason Subarus tend to get good tire life when running excessive negative camber.

Stock adjustments will get you up to -1.5 degrees. With aftermarket camber plates, one can achieve up to -6 degrees of camber. Most Subaru drivers are happy with between -1.5 and -2.0 and notice no ill wear patterns on their tires. I personally run -3 degrees on all 4 wheels on my Legacy, and I've driven 10,000+ miles like that and I have had no abnormal tire wear.

Camber should match side to side (per axle). Generally, there is a tolerance of about .5 degrees before there is a drivability concern. Usually anything over .5 degrees split will cause the vehicle to pull towards the more positive side (wheel with the most positive camber).

On our cars, Camber is adjustable by an essentric bolt in the steering knuckle in the front.

Our cars do not have a factory rear camber adjustment, however I've been able to adjust rear camber by close to 1 degrees by loosening the knuckle bolts and manually pushing in or pulling out the entire knuckle, and tightening the bolts back up. There are aftermarket camber bolts and adjustable lateral links available to allow further camber adjustment in the rear.

Caster

http://img.photobucket.com/albums/v2...ign/caster.jpg

Caster is the angle of the upper and lower steering pivots viewed from the side.

To best explain steering pivot, its the lower part of the suspension that turns, and the upper part that turns. In a Subaru, this is the lower ball joint and the strut mount (top hat).

Caster has a direct impact on steering effort and lateral stability.

Negative caster will cause the vehicle to wander at high speeds, reducing lateral stability. But on the plus side, it will reduce steering effort.

Postitive caster will help the vehicle retain lateral stability at high speeds, but in turn it will raise your steering effort a little bit. Most cars are set up out of the factory with about 5 degrees of positive caster. Some German cars have as much as 9 degrees of positive caster.

Caster has little to no effect on tire wear. Like camber, caster has a tolerance of about .5 degrees from side to side. If there is a split of more then .5 degrees, the vehicle will usually pull to the more negative side.

In a Subaru (and most other cars on the road) caster is not adjustable. If there are caster problems, its a good indication that there is a bent steering / suspension component from some kind of accident.

Toe

http://img.photobucket.com/albums/v2...lign/toein.jpg
http://img.photobucket.com/albums/v2...ign/toeout.jpg

Toe is probably the single most important alignment angle. Toe identifies the direction a wheel is turned compared to the centerline of the vehicle. Postive toe is the wheel turned out, negative toe is the wheel turned in.

Toe being outside of specifications can cause a few different problems. The big ones are abnormal tire wear, vehicle pulling, and a crooked steering wheel. The ideal toe setting is 0 degrees on all 4 wheels.

On our cars, toe is adjustable on all 4 wheels. If further adjustment is needed on rear tires, aftermarket lateral links are available that allow more adjustment.

Steering Axis Inclination (SAI)

http://img.photobucket.com/albums/v2.../Align/sai.jpg

Steering Axis Inclination (also called SAI) is the angle of the steering pivots viewed from the front.

Like caster, SAI can help improve directional stability by reducing the scrub radius.

SAI is NOT adjustable on any vehicle. If SAI is outside of specifications, its a good indication that there is a bent or broken steering / suspension component. SAI is mainly used by alignment technicians to help them diagnose bent parts.

Included Angle

http://img.photobucket.com/albums/v2...ludedangle.jpg

Like SAI, Included Angle (also called IA) is a diagnostic angle. Its the sum of SAI + Camber. It is also used to help diagnose bent suspension parts. IA is NOT adjustable.

Scrub Radius

http://img.photobucket.com/albums/v2...ubradius-1.jpg


Scrub Radios is the distance between the extended lines of the steering axis and the tires centerline where the tread contacts the road.

Scrub radius is NOT adjustable, however it can be changed a few different ways. Bent suspension parts will change your scrub radius. If this is the case, the vehicle will pull hard in one direction since the scrub radius does not match on each side. Another way scrub radius changes is by installing different offset wheels. This can have a negative impact on vehicle handling.

Setback

http://img.photobucket.com/albums/v2...gn/setback.jpg


Setback is the term used when one wheel on an axle is positioned further back then the other wheel. There is generally a tolerance of about .25 inches. Anything more then that indicates that there is a bent / broken suspension component.

Thrust Angle

http://img.photobucket.com/albums/v2...hrustangle.jpg

Thrust angle is the diection that the rear wheels are facing in relation to the center line of a vehicle. Thrust angle IS adjustable on almost all vehicles. On a Subaru, you adjust rear toe to correct the thrust angle.

If the thrust angle is out of spec, then the vehicle will "dog track". As well, it will handle differently when turning left vs right.

On a solid rear axle vehicle (like a truck), if the thrust angle is not in spec...then usually the vehicle must visit a body shop for frame repair. Sometimes the rear diff can be re-positioned to compensate for the thrust angle however.

Ride Height

If I need to explain this one, there are some problems lol.

Ride height is not adjustable on Subarus unless you have an aftermarket coilover system installed. You can get a lower ride height by installing lowering springs on your factory struts too.

Any time you change your ride height, you MUST do an alignment since it will affect your camber and toe on all 4 wheels.

Toe Out On Turn

http://img.photobucket.com/albums/v2...outonturns.jpg


During a turn, the inside wheel of the turn will turn sharper then the outside wheel will. This is the "toe out on turn". See the above illustration to understand.

If this is outside of specs, its likely cause by a bent tie rod or steering arm.

Offset

http://img.photobucket.com/albums/v2...ign/offset.jpg

Zero Offset - The hub of the wheel is in line with the centerline of the tire
Negative Offset - The hub of the wheel is towards the inside of the vehicle
Positive Offset - The hub of the wheel is towards the outside of the vehicle

By changing wheels to a set with a different offset, you effect toe out on turn and scrub radius.

Alignment images from http://www.anewtoronto.com/wheel%20alignment.html


SUGGESTED ALIGNMENT SETUP

I will give my person reccomendations here based on a few different setups and driving styles. This is not a "one size fits all" chart, however its a good starting point. You will likely have to tweak the following numbers slightly to find something that feels good to you. These numbers are just what I have found works for me.

Stock Suspension - Daily Driver

Front Toe : 0
Front Camber : -.8
Rear Toe : 0
Rear Camber : .6

Stock Suspension (including WRX) - Aggressive Cornering

Front Toe : 0
Front Camber : -1.5 give or take a bit. Max out the camber bolts and make have 0 cross camber
Rear Toe : 0
Rear Camber : -1 max out having 0 cross camber

Coilovers - Daily Driving

Same as stock

Coilovers - Drag

Front Toe : 0
Front Camber : 0
Rear Toe : 0
Rear Camber : 0

Coilovers - Aggressive Cornering

Front Toe : 0
Front Camber : -3.2
Rear Toe : 0
Rear Camber : -3

Making your alignment work for you

Any alignment changes you make have a direct impact on the way your vehicle handles. One of the biggest things you can change is the handling balance of your car by reducing understeer or oversteer.

Reduce Understeer : run more negative camber in the front. This is probably the single most important thing that anyone can do to make their car handle better. This will bring the car to a more "neutral" steering car.

More Understeer : run more positive camber in the front. This will likely make your car undrivable if you start going into positive numbers though. BE CAREFUL with this. If you're in the rain, snow, or ice and you're running positive camber, you will likely crash into a big tree and have an airbag blow up in your face.

Getting your alignment done

Almost any automotive shop can do an alignment for you. "Stock" alignment settings for Subarus SUCK. Its better to walk in knowing the alignment you want. Ask to talk to the tech doing your alignment so you can explain to them what you want out of the car and they can help you decide what settings are best. Keep in mind though, that running a bit of negative camber on our cars WILL NOT wear out your tires like it will on most other vehicles, no matter what the tech tells you.

Make it VERY clear that you want 0 toe, 0 thrust angle, and 0 camber split on both axles. Make sure that they adjust camber on all 4 wheels as well. It blows my mind how many half ass alignments I've seen done where someone doesn't bother to touch camber....or they will get everything "in the green" and call it a day, but the car leaves with a .7 split on the front toe. If the tech tells you that camber is not adjustable, teach them something about your car. Earlier in this article I explained how both front and rear camber are adjustable. If for some reason the shop wants to charge you more to do this, walk away from them. This is part of a NORMAL alignment and does NOT cost extra to do.

ALWAYS ask for a before and after printout of your alignment.

If possible, watch the tech do your alignment. That way you can at least pretend you know what he is doing, and he is less likely to half ass it.

A fair price for an alignment is anywhere between $75 - $100.

Your alignment will likely come with a warranty. However, this warranty is void if you "race" or "abuse" your vehicle. Meaning if on your way home you go through the corners like a bat out of hell, it will void your alignment warranty if the shop finds out. So when you take your car back, don't mention that you have raced or "abused" your car. Some shops offer a "lifetime warranty" on their alignments. This usually runs about $150. If you plan on keeping your car for a long time, this may be worth it. If you do this, I suggest taking your car back about every 3 months to have everything checked.

edited

BY : Jac Wagon

Hey Zues, I found this on a 240 site. Good info for those who are new to the world of suspension.

There are 2 kinds of springs. Progressive, and Linear.

With progressive springs, as they compress the lighter rate coils compress, and force higher rate colis into action. Effectively increasing spring rate as they are compressed. Stock 240sx springs are progressive. (most stock springs are.) This type of spring is good for street driving b/c they are comfortable over small bumps, but tighten up as you start turning, or braking harder.

Linear springs are the same spring rate no matter how much they are compressed. Almost all coilover systems come with linear rate springs. Linear springs are much better for sport driving, b/c they are much mroe predictable, and make tuning your suspension much easier.

You can only preload springs with threaded shock body coilovers.

To preload a spring, you compress it b/w the upper and lower spring perches by adjusting the lower collar with the spanner wrench.

With linear springs:
When you put the weight of a corner of a car (probably around 700lbs) over your spring it compresses to absorb that weight. With 400lb spring, it will compress about 1 3/4". So, if you start with the lower collar so that it is just tight enough to hold the top of the spring against the upper perch this would be 0 preload. Raise the collar 1 3/4", and you now have 700lb's of preload. (arbitrary #'s for the sake of illustration.) Since you have preloaded the spring, the same weight as the car's corner, when you put the car on that spring, it will not compress at all, and will simply sit on top of the spring. If you were to hit a bump, the force would still compress the spring the same amount it normally would if you had set the spring to 0 preload. Now if you set the spring to say 900lbs of preload, when you hit the bump (say its a bump that generates around 250lbs of upward force), the spring will compress much less b/c the spring is already beyond the load specified to absorb the bump. Since there is only 50lbs beyond the preload, the spring will only compress about 1/8th inch, and the car will likely be launched over the bump.

You will likely never ever preload a spring beyond the weight of the corner of the car it is on for that exact reason. Springs are there to absorb bumps, if there are any bumps at all, this is a bad idea.

What good is preloading the spring then?

It can provide you with more suspension travel in certain situations. In the ideal world, having the spring at 0 preload would place the piston inside the shock exactly halfway through it's stroke (middle of shock) once the car's weight is resting on the spring. This is almost never the case. by preloading the spring, you can adjust the amount of rebound, or compression travel you have in the shock. If you preload like 200lbs, this will give you more compression travel, and will help keep your car from bottoming out when cornering. You have to be careful though, b/c you don't want to sacrifice too much rebound travel, or you could cause all sorts of other problems.

Progressive springs:
With progressive springs, preloading the spring does all the same things as linear springs, but it also increases the initial rate of the spring. So say you have a spring with a 200lb/in initial rate, and a 400lb/in max rate. (all progressive springs are rated this way.) Preloading 200lb's will compress the spring just under 1". Since the rate goes up with a function, it will have increased to probably somewhere around 250lb/in by the time you reach a 200lb preload. So now your initial rate is 250lb/in, with a max 0f 400lb/in.

You will likely never deal with this though, b/c very few coilover systems come with progressive springs, and remember you can't preload without adjustable spring perches. (coilovers)

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also should quicklink to the post # on the first post so ppl dont have to scroll

Already done. It wasnt like that at first because I was trying to snatch the first several posts before someone replied lol. Now I'm going back and editing everything

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