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1. Am I correct in assuming that installing this REAR sway bar will reduce understeer and body roll during cornering?

2. I shouldn't get a front sway bar, right? Because this will increase understeer?

3. Do I need a rear upper strut bar if I get the 19mm RSX sway bar?

4. What do I need to install the RSX rear sway bar? Can I DIY? What are bushings?

5. Those of you who have installed it already, would you recommend it?

Thanks,

IronFist

 
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1) i think it will decrease oversteer, meaning your back wheels won't roll or slide as much.
2) no if you get a front sway bar, you might be in the same position you are in now with very high oversteer because the front bar would be way thicker than the rear. I thought about getting a bigger front bar but I think you should only upgrade the front if you upgrade the rear to at least a 20-22mm bar.
3) No you don't need any other bars
4) There is a diy at www.xenja.com that is slikor's site. It is easy to follow, just don't put it on upside down like I did. the bushings along with brackets hold the bar to the chassis.
5) i recommend it. I think i would have rather had thicker bars like the progress bars, but with the TCS it is kind of hard. But it is a good middle to be at.

 
Rep Power: 425

Rob you got it backwards... it reduces understeer by allowing more weight to shift in the back and still keeps the car planted on both sides. Its like a stiffer spring... when you turn, the car wants to roll, when it does, it'll lift most of the weight off one side. The stiffer bar, holds the inner side of the car down for longer, keeping more weight on the tire. Going too thick with a rear bar can induce oversteer when pushed hard... you make the rear so stiff it won't move, and then the tires have no where to go (they don't turn, they just follow) and if you turn too hard, they can't follow and they start going sideways... which is what causes you to slide. Increasing the front WILL take you back to square one with understeer/pushing problems.
You don't need extra bars, although people will say to get a lower rear tie bar just for safe measure.

 
Rep Power: 414

Ok so let me get this straight. Oversteer is when the rear end kicks out or slides? Why would increasing the size of the rear bar decrease understeer? Wouldn't the rear bar provide MORE stability to the rear thus increasing the amount of stress the rear can take? This whole oversteer/understeer thing is kind of confusing for some of us.

 
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Click here for changes to make for understeer/oversteer corrections

Here's another one


I found tons of crap on this by searching "reduce understeer" and "decrease understeer" on google. there's lots of info if you want to read up.
Road cars are set up to understeer because its safer. Its something thats easier to correct since the car is still pointed in the right direction. Oversteer is nasty if it's not controllable. Really what you're doing is not inducing oversteer by stiffening the bar, but neutralizing the flex in the front and rear. You want both ends of the car to be balanced, which greatly improves handling. If you go too far with it, then you get oversteer.

 
Rep Power: 382

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Its a bit complex, but the basic rule is: The side of the car (Front or rear) that has the higher proportioal spring rate (to the static weight on that end of the car) will have more weight transfered to it during a turn. this all deals with Tire traction. (I'm stealing this next part from another site)

Tire Lateral Loas Transfer Distributoin (TLLTD) AKA: Roll Couple Distrobution

TLLTD stands for Tire Lateral Load Transfer Distribution. While this term may sound complex, it simply measures the front-to-rear balance of how lateral load is transferred in a cornering maneuver. It is commonly used to compare the rate of lateral traction loss between the front and rear tires.

Put simply, there is only so much force that a tire can handle. When we ask more of the tire than the tire can deliver, it "saturates," or loses traction. If the front tires saturate before the rear tires, then we call this understeer or push-which means that the car tends to continue moving in the original direction, even though the wheels are turned.

If the rear tires saturate before the front tires, then we call this oversteer or loose-which means that the rear of the car tends to swing around faster than the front, causing a spin. When neither of these conditions prevail consistently, then we describe the chassis as balanced.

We can measure and compare the steady-state understeer and oversteer characteristics of a vehicle by assigning a lateral load transfer percentage of the front relative to the rear. A TLLTD value equal to 50 percent indicates that the chassis is balanced-or both the front and rear tires tend to lose traction at roughly the same time. A front TLLTD value greater than 50 percent indicates that the front tires lose traction more quickly than the rear tires-resulting in understeer. And a front TLLTD value lower than 50 percent indicates that the rear tires tend to lose traction more quickly than the front-resulting in oversteer.

It is important to note that our discussion of TLLTD only considers steady-state cornering maneuvers, such as a long 270-degree on-ramp or off-ramp. Moderate-to-aggressive throttle or brake application can upset this balance during a transient condition, briefly transitioning a vehicle from understeer to oversteer.



The Effect of Anti-Roll Bars Upon TLLTD

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Ideally, you now understand how an anti-roll bar can be used to limit body roll, and you understand that reduced body roll can lead to a reduction in adverse camber changes for better tire traction. But what may not be obvious is the effect of anti-roll bar changes upon TLLTD (understeer and oversteer.)

In fact, given the above information, one might even assume that a firmer anti-roll bar, which leads to better camber control, would lead to better traction. If we add a firmer anti-roll bar to the front, traction loss diminishes, so understeer is reduced, right?

Wrong. Let's evaluate more closely the meaning of TLLTD-tire lateral load transfer distribution. Stated another way, we might describe TLLTD as the relative demand of side-to-side energy control that is placed upon the tires. Because a firmer anti-roll bar allows less deflection, it will transfer side-to-side energy (lateral loads) at a faster rate.

As the rate of lateral load transfer increases, additional demands are placed upon the tire. So if we install a firmer anti-roll bar in the front, then we increase the distribution of lateral load transfer toward the front tires. This increases the front TLLTD value, which will result in additional understeer, holding all else constant.

The same logic also holds true in the rear. A firmer anti-roll bar in the rear will increase the rate of lateral load transfer, placing more demand upon the rear tires, accelerating lateral traction loss and creating more oversteer, holding all else constant.

This is why blindly adding parts to your car may not produce the desired results. A wise consumer consults with-and buys from-knowledgeable experts that have the tools to make informed tuning recommendations.



I Want a 50 Percent TLLTD On My Car, Right?

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Since on paper a 50-percent TLLTD indicates a balanced chassis, many enthusiasts are tempted to jump to the conclusion that this is therefore desirable. They may think that all cars should obviously come this way from the factory. Unfortunately, this is not the case-and the considerations are not that simple.

In reality, a car with a 50-percent TLLTD is literally on the constant brink of oversteer. And there are many factors that can quickly and easily take the car from the brink into a full-scale, out-of-control, spinning-in-circles disaster.

For starters, consider the effects of weather conditions that might create a wet or icy road surface. Or imagine that the driver happens to apply too much brake late into a turn-a common mistake among novice drivers. Or consider the effects of varying tire temperatures, tire pressures, or tire wear-all of which will have major impacts upon lateral traction thresholds. And of course, varying weight distribution, as a result of changing fuel tank levels, passengers, or the number of subwoofers in the trunk, will also impact TLLTD.

With all of these things to consider, automotive design engineers are forced to create a more conservative TLLTD. As a result, they intentionally target higher front TLLTD values so that stock vehicles will be prone to understeer-the assumption being that understeer is safer and more predictable for the average driver.

As a general rule, an average street-driving enthusiast is probably willing to accept some compromises-within reason-of a more aggressive TLLTD in exchange for better handling. A suitable target is probably a front TLLTD value of approximately 58 percent, a value that is considered aggressive, but suitable for street driving.



Hope this helps.
Really bad *** PDF that goes deeper in to handling

ANother Something on Shock tuning Where I stole it from

 
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Cool thanks!! I guess my assumptions were wrong about adding the bars, but I am glad that it seems to be an easily made assumption! Anyway, I think all of IronFist's questions were answered.

 
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Yes, let me read that once again...

So before I read it again, it would improve my handling if I added the 19mm rear sway bar and left the front one alone, right?

Those of you who have added it, what have you noticed?

Thanks,

IronFist

 
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Yes because:

In case no one realizes it, the weight distribution on our cars is 60% front/40% rear. A thicker rear bar "increases the rate of lateral load transfer" adding stability to the rear of the car making the entire car turn better.

 
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I read an article about RealTimeRacing's RSX-S. One of the drivers (Pierre Kleinubing) says about racing front-wheel drive cars: