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Discussion Starter · #1 ·
I want to get rid of as much body roll as possible without breaking the bank and making the ride ridiculously uncomfortable. I have looked at some threads on here that are a couple years old, so I wanted to see what people are using now...if much has changed in the suspension part market.
 

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What is your definition of ridiculously uncomfortable? Have you ridden in any other cars to gauge your tolerance?

Bigger sway bars will reduce roll without increasing NVH, but will reduce grip. What's more important to you, handling or body roll?
 

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Discussion Starter · #3 ·
I rode in an RS recently, loved it. I think body roll and handling are probably equally as important. Maybe I do have to break the bank?
 

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Discussion Starter · #5 ·
I was looking at those, I like the idea of just throwing 4 of those in...and they have the B8's which I hear are nice.

I'm not really set on a budget...more just lining stuff up to see how much money I'm going to need. Planning on waiting till spring to start really toying with her.
 

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I installed Steeda springs and rear sway bar on my 2015. Feels great rite now, but I do think I am maxing out the factory struts/shocks. The bad part is that I can't find Bilstein B8 struts for my year springs. If I did it over I would probably look into the H&R coil over kit. Not much more than a spring, strut, shock replacement and you get lighter weight, better dampers, and height adjustability. I am hoping by time I need to replace dampers the B8s will be available, but those combined with aftermarket traditional springs are not much cheaper than a lot of coil over kits on the market.
 

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Start with the rear sway (cheap, super easy installation) and go from there. You might be really surprised how big a difference that one part alone makes.
 
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I disagree. If you plan on keeping the car you will need to get better struts sooner or later anyways. I just installed the clubsports and body roll is basically all gone. Swapping the RSB will mess the cars natural handling up more than you think
 

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I agree with jalapeno. Also, I would recommend some reading on suspension design and theory. If you just start swapping suspension parts you may end up with a nice look but you will most likely have much less grip than you did stock.

Take a look at some of the info here.
http://www.motoiq.com/Tech/TheUltimateGuidetoSuspensionHandling.aspx
I think parts 2,3, and 4 will be of particular interest.



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Glad to hear it concerning the clubsport suspension parts, have been eyeing those since I began looking at parts to curb the body roll myself.
 

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I agree with jalapeno. Also, I would recommend some reading on suspension design and theory. If you just start swapping suspension parts you may end up with a nice look but you will most likely have much less grip than you did stock.

Take a look at some of the info here.
The Ultimate Guide to Suspension & Handling
I think parts 2,3, and 4 will be of particular interest.

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I have some reading to do tonight! Thanks for what appears to be a very helpful website!!
 

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^ This is true.

The sway bar actually doesn't do as much to control sway, which I am guessing most people are referring to the cars body roll, as it does tuning the balance of the suspension. Adding the rear sway bar on the Focus ST reduces the feeling of the back end feeling loose. If you want to reduce body roll you need stiffer springs.
 

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I would try adding both larger front and rear anti sway bars and keep the stock spring/shocks until you're ready to stiffen it up. I have the eibach front and steeda rear bars and body roll is reduced substantially. Although installing the front bar is a bit more involved than the rear bar, I feel that it was necessary to keep the wheels and tires more upright during hard (autocross) cornering. While you have the sub frame dropped for the front bar install, this is a great time to swap the lower control arm bushings for polyurethane bushings. The poly bushings will compress less than the stock rubber bushings, thus also helping to keep the wheel and tire perpendicular to the pavement. I've been told the bilstein shocks ride better than the koni yellows, I have the konis and my ride is considerably jouncy, primarily in the rear. I haven't experienced reduced grip from the addition of a front anti sway bar, I think it helps to keep my inside rear tire on the ground longer so that it can contribute to the cornering load, thus increasing overall grip. 13615185_10210126021972242_8401812008169975589_n.jpg
 

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In a CliffsNotes version, how does reducing body roll (mainly from a rear sway bar install) reduce grip?
Here is how I would explain it. I'm not sure my explanation is correct but it is the theory that I'm currently operating under. A stiffer rear bar on the ST will cause the rear inside wheel to lift off the ground sooner, once the tire leaves the pavement, it is not contributing to generating cornering force. As you increase the roll stiffness using anti sway bars, the outside wheel (when turning) causes the anti sway bar lever arm to move up (relative to the car body). The opposite side of the bar on the inside wheel also tries to move up in resistance to the weight transfer of the body trying to keep the bar moving down. With enough anti sway bar roll stiffness, you would eventually lift the inside front wheel. So with both the front and rear anti sway bars, they keep the body from rolling by gradually reducing the downward force on the inside tire which also gradually reduces the amount of grip that tire can contribute to the overall cornering force. The greatest cornering force you can achieve lies somewhere before the roll stiffness lifts the tire off the road. This may explain why stiffer springs rather than stiffer anti-sway bars may offer the ultimate handling since you don't have the anti sway bar trying to lift the inside wheel, reducing how hard that tire is being pushed into the pavement and thus reducing grip.
 

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Here is how I would explain it. I'm not sure my explanation is correct but it is the theory that I'm currently operating under. A stiffer rear bar on the ST will cause the rear inside wheel to lift off the ground sooner, once the tire leaves the pavement, it is not contributing to generating cornering force. As you increase the roll stiffness using anti sway bars, the outside wheel (when turning) causes the anti sway bar lever arm to move up (relative to the car body). The opposite side of the bar on the inside wheel also tries to move up in resistance to the weight transfer of the body trying to keep the bar moving down. With enough anti sway bar roll stiffness, you would eventually lift the inside front wheel. So with both the front and rear anti sway bars, they keep the body from rolling by gradually reducing the downward force on the inside tire which also gradually reduces the amount of grip that tire can contribute to the overall cornering force. The greatest cornering force you can achieve lies somewhere before the roll stiffness lifts the tire off the road. This may explain why stiffer springs rather than stiffer anti-sway bars may offer the ultimate handling since you don't have the anti sway bar trying to lift the inside wheel, reducing how hard that tire is being pushed into the pavement and thus reducing grip.
Bingo.

And why it seems people with street cars run bigger bars and softer springs, it rides better and they don't need the ultimate cornering grip. On a more dedicated track car or someone that loves a harsh ride, they can run much stiffer springs to get the grip they need and control roll, and then use sways to fine tune the balance.
 

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My experience is that it should be springs (dampers) first and sway bars second as a fine tuning element. As stated above, swaybars are good as a fine tuning element but not as the primary method of improving handling. Springs allow the car to resist roll by holding the car up, and dampers aid/modify the rate that the springs compress or rebound by adding mechanical/fluid resistance via the valving. If you could tune your car for a specific track or situation you'd dial in the springs and dampers and may not need a swaybar. The limitation is that you'd need very stiff springs and aggressive damper settings to handle the cornering which would make the ride uncomfortable (not an issue for racing). So here swaybars come into play bc they only become part of the spring forces when cornering and have little effect on straight line ride comfort. Ideally the car springs and dampers are matched to whatever purpose the car is being used....but even then the maybe a desire to slightly alter (stiffen) the handling/cornering depending on traction conditions, road, weather, and driving style.

If you rely on the swaybars for a large portion of your spring rates, then you'll need a fairly large bar (stiff)...this has its limitations. The basic result of a larger rear bar is that it transfers more force and at a faster rate to the opposite side of the rear axle and to the outer front tire. This makes the car feel much more stable, aids turn-in feel, and increases the rate of weight transfer without as much roll...feels more like a go- kart. As speeds increase the bar starts to try to lift the inside rear corner, and further loads the outer front tire. The front tire will gain more downward force/grip until it exceeds the capability of the tire then it will push (understeer)....and this setup will increase cornering speeds up to the limits of the tire/slip angle. At the same time the inner rear tire starts to lift thus reducing rear traction (gradual loss of a tire contact reduces grip) and by doing so induces more and more rotation (oversteer). By increasing and adjusting the rear bar the car can be "dialed in" to suit the driver and the road/surface conditions.

So what are the draw backs? As previously mentioned the rear bar will start to lift the inner wheel and at some point the loss of grip/traction can drop enough that the outer tire can not provide enough grip for the car to remain on course...and it "snap over steers" off the road. Additionally it robs the car of suspension travel....potentially upsetting the car over bumps while cornering. It also tends to decrease suspension compliance and can affect even straight line ride quality.

Many times a simple increase in the rear bar stiffness can significantly improve the car's handling without negative effect if done conservatively. Adding a rear bar that is 1 or 2 mm thicker than stock size (15 - 30% increase in spring rate) on a stock suspension will allow the driver to find a sweet spot and reduce the roll, improve turn-in feel and aid cornering without "over powering" the springs and dampers. Unfortunately some people feel that more is better and that no roll = better handling. Unfortunately this is not the case and they put way to big of a bar on the car. While it feels great at 8/10ths or below, it starts to loose its effectiveness near the limits or in changing weather conditions, creating an overly loose rear or worse...snap oversteer.

If you are racing or autox your car then a big bar maybe ideal, or if you've upped your spring rates and dampers and added stickier tires you may need/want a bigger bar...but even then many people simply go to far.

Recommendation: If you have stock suspension and you do not race or very infrequently race, keep the rear bar increase under 3mm (~ 50% stiffer) and ideally have a bar with 2 or 3 hole adjustment. If you now are upping the spring rates and dampers as well as sticky tires then the upper limit might be to increase bar size 3-4 mm (50- 70% spring rate increase)...much beyond this is too much rear bar....remember a little goes along way.

**If you are racing these suggestions really don't apply bc the car is dedicated to a narrow band of use and weather conditions and in a controlled situation.
 

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Woah...awesome reading guys.

So is it fair to say that your goal is just a great handling car on good curvy roads where you're not pushing it no where near the limits of the car or the tires, you can still find benefit in a RSB if not overdone? Also, I fully understand the theory you guys are relaying about the tendency to lift the inside rear tire if too much bar is added and the car is pushed to far, but would it again be fair to say that up prior to that point where the inside rear tire is maintaining good contact, grip is still greatly improved with a stiffer RSB? The comments about the stiffer RSB reducing grip only become a factor when you've found that limit and the inside rear tire starts to lose contact? But therein lies the magic question...where is that point of which that occurs? Is it so extreme that you'd only see this on a track under "near the edge" conditions? I'm guessing from the reading I've done (and as long as you don't throw a ridiculous bar on the rear), this may not be a factor on the street, even on an aggressive curvy road...unless you're just driving like an animal on said roads, lol.

And this seems like a good place for me to add this...seems from my reading a lot of guys go after the rear bar on these cars instead of the front or both...is there a basic, overarching, simple explanation for this...or did I miss something?
 
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