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hello.

i've heard of people switching their stock civic rear swaybar for a rsx swaybar.
mt question is this:
if the stock in civic is 15.9/12 front/rear
and the stock rsx is: 23/19 front/rear
then swithing civic/rsx will be 15.9/19 front/rear



wouldn't this cerate mad oversteer?
don't you want front slightly larger? (3-5mm)

thanks.

 
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Our cars are Tuned to understeer Excessivly, and bumping up to a 19mm rear bar helps tune out that understeer.

I have H&R sport springs and The RSX rear bar, and At the limits of traction the car still wants to understeer through most corners. If I enter correctly I can get the rear end to rotate but its tough to do. So, for a street car the 19mm RSX bar is perfect. it reduces a great amount of Understeer but dosn't make the car Dangerous for the Average driver. Just know that if you are too quick with steering imputs the car will want to bring the rear end around, but thats driver error any way. And having a little oversteer is not a bad thing any way, so long as you dont do any thing stupid to make it worse. Like push on the breaks or lift off the throttle.

the more you tune the cars handling towars performance, the more you have to drive the car properly

 
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yes that's true, but when i look for aftermarket sways, i find sizes that are like 27/22, 25/21, 20/16, 24/23.5, etc.
all have a larger diameter in front than the rear.

 
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Most aftermarket sway bar setups are rather Mild with their handling. As in They are designed for the Average driver on the street, not some one who autocrosses or does track days. What this means is that although the car will handle much better with one of these set ups, at the limits of traction the car is still going to understeer. which is Safe and predictible for 99% of the drivers on the street. In a Performance application, understeer is less then desirable, So having a set up that creates a little bit of oversteer is much more desirable. also, what cars are you getting these #s from? FWD cars will have a different sway bar setup then RWD cars.

 
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i've been shopping for civic sway bars, not RWD cars.
those numbers are what the sizes the swaybars that are artermarket..
suspention techincs, progress, elttlebroc, (can't spell), nuespeed, etc.

the other numbers (stock) came from honda.com

so you are sayn' i should buy diffrent brand front sway bars than the rear, depending on the amount of understeer i want?

like use a stock rsx front sway bar (will that even fit???) and a neuspeed rear sway bar? that would be a 23/22 mm. set-up?

or should i use a smaller front than rear? like a ettlebrok front and neuspeed rear? a 19/22 mm. ser-up?

 
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Precisely! what you are tuning is called Roll couple Distribution. its the ratio of roll resistanes on the front of the car Vs the rear of the car.

In a turn a car can only do one of 3 things, it can understeer, nutural steer or oversteer. when and where the car does one of these 3 things is constantly changing due to corner speeds, how you enter the corner, ect.,.... meaning that it is IMPOSSIBLE to tune a car to be nutural in every corner. So for a performace set up, you'd tune the suspension to be biased more twards Oversteer rather then understeer, on the street cars are tuned to Understeer long before they ever oversteer.

So for tuning:
If the car understeers then there is either an excess of roll resistance on the front or too little roll resistance on the rear. and if the car oversteers then there is either too much roll reistance on the rear or to little on the front.

How you want the car to handle will determin what parts you need to get, and to chang the roll resistance Front or rear, you can change either the spings or the Anti-roll bars. The easiest way In my opinion is to get an adjustble anti-roll bar, that way if you find the car oversteering too much or understeering, you can tune it out by adjusting the strength of the bar. Depending on what springs you have will also determin when the car will oversteer/nuturalsteer/understeer so take those in to account too.

Like I said, I have the 19mm rear bar and the stock front bar with H&R sport springs, and the car still understeers through most corners, Though MUCH less then it did before.

 
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I think the stock front sway bar is bigger than 15.9.. when I put my progress front on it was only a little bigger but is solid rather than hollow. anyways I've got the 27mm front and 22 mm rear and the car handles great... I don't think it understeeres or oversteers.. .it just goes in the direction I want it to, and when I take a turn I can take them fast without losing too much acceleration....

 
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Your probably not pushing the car to its limits then, which is a good thing on the street. Go autocrossing, and you'll find that the car probably still understeers at the limits of traction. On the street where you never reach that limit (Good) those set ups are perfictly fine. But like I said For motorsports its better to have a car that slightly oversteers rather then slightly understeers.

 
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The stock front sway bar for a 01-02 is 25.4mm exactly 1". They changed it to 15.9 in 03 i believe.

 
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rob's correct.

honda went softer.

depending on your driving preference, u should upgrade the front sway bar to a bigger bar too.

it was:

01: 25/12
02: 25/13
03: 15.9/12

(and er.. some models years dont have rear sway bars... ie: 01 only ex have rear sway bar... 02, ex/lx and maybe hx has it... )

its all about how u want ur car to handle.

ideally, I believe we all want neutral handling.. where the car doesn't understeer or oversteer.. it just goes where u want it to go..

but... getting to that middle perfect point isn't something swapping sway bars will do.

 
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well...i have a 02, so that's sweet!!!
that means the rsx will put me at 25/19......that sounds good... imp:

 
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The problem about tuning for Nutural steer, is that its a Transient state. If you tune the car to be nutural in one corner, in the next it may Understeer or oversteer.

Think of the three states of handling as a Lininar graph. with understeer on the left, Oversteer on the right and Nuturalsteer in the middle. Now values of this graph change for each corner, and since your suspension Values Dont change, then you can see that tuning for NuturalSteer is impossible to do for EVERY corner. Now this is dealing with the car at the limits of traction, so this dosnt really apply to the street. With this in mind, some one tuning for Racing weather it be Autocross or road racing will tune the car more biased twards Oversteer rather then understeer. This is because Oversteer in a racing application is MUCh better then understeer, because with oversteer you can use it to line up your corner exits and be on the gas that much sooner, where with understeer your pretty much screwed. On the street where you will not get any where near the limits of traction (at least I hope not) then you can have the car tuned more "Mildly" twards understeer, and since you never reach the limits of traction you'll never reach that point of understeer. This is Great for the street, but Sucks for a Race application.

2 examples of Milidly Preped civcs in autocross
Bot cars have H&R Sport Springs, but one has the RSX 19 mm Rear anti-roll bar(Car 1) and the other has the 22MM Progress Rear bar(Car 2). (Car 3) has H&R sport springs and Stock Roll bars(As a control) (Both Car 1 and 3 is my car before and after examples)

1. Car 3, when I ran autocross with that setup, it would understeer in all but the fastest corners, this would kill my times because I would have to enter corners Slower then I wanted to. When I switched to Car 1 set up, I instanly Droped 1 to 2 seconds off my times, and the car would only understeer in the Slower/sharper corners. and In certin corners, if I got on the gas a little, I could bring the rear end around and create some oversteer.

2. Car 2, according to the guy that was driving this car (When I autocrossed in San Diego) he could steer the car with the gas. Why would he want to steer the car with the gas???? the answer is simple, If he could use the trottle to help turn the car, he could also maintain higher speeds through the corner giving him not only an advantage in the corner its self, but on corner exit, he would have the advantage of acclerating sooner because the car would be pointed in the right direction sooner. Now on that day of racing he was 4 seconds faster them me. Now this is all not due the the larger bar, and I believe that I could have shaved off 2 seconds if I had more time on that track (To get use to the querks), but that still leaves 2 seconds.....

So my point is about all this is, IF a civic with the stock Front sway bar and the 22 mm rear sway bar is Set up Pretty damn good for autocross, then if you were to increace the size of the front sway bar then you would loose a lot of that Throttle steering and loose a lot of time.

So i reiterate, MOST Front and Rear anti-roll bar combos are designed for the street, and therfore are tuned to understeer at the limits of traction. This is perfictly fine and Dandy for the street but is LESS then desierable in a race application. so when you decide on getting these parts, Look at how you are going to use them and choose accordingly. But be warned, the more you tune the car for a race aplication, the less forgiving that car will be to your mistakes, so you as a driver will have to pay more attention to your driving.

 
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Funny thing is, I can say the same thing for the 22mm rear bar.

EDIT: & GCs.

 
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Have you done any track driving or autocross? I find that the level of driving that we think is "the limits" on the street are actually no where near how hard you could actually push the car in a controled inviornment like a track day or an autocross event. (I know my limit on the street is no where near how hard i push on the track) Try it once, I think you'll be able to instigate more oversteer in the corners then you previously thought possible.

 
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Yeah, that's probably 'cause tracks have smooth surfaces. I have a pretty stiff setup and I lose traction when I hit a small bump or hole when taking a corner aggresively. On the track I could push it to the limits of traction. On the street you have to take into account the uneven surface. Maybe a suspension setup that's less stiff would work better for the street?

 
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Thats exactly what it is. Which brings up the topic of Wheel rates and Suspension Frequencies. But thats another thread entirly....