Swaybar vs. lowering springs

[why?]

i didn't buy the yaris because it was an economy car, i bought it because it was what I wanted. It is just a side benefit that i can get 38 mpg.

Anything worthwhile in the sporty car segment is at least 6 or 7 grand higher, and can't touch the fe.

[Kaotic Lazagna]

It's all about a the modding culture. Plus the car gets awesome gas mileage to boot.

[CtrlAltDefeat]

Personally I bought springs first then a sway bar later. The stiffer suspension and lower center of gravity makes the car feel a lot better in curves and look sportier. However, Loren knows a lot about these kind of things, so if looks are more important then at the limit handling, then get springs, if you plan on doing autox or hard maneuvers, follow Loren's advice... (this is my opinion any ways)

[sickpuppy1]

Now from a "practical" point of view, the Swaybar is good sense, in that a more nuetral car is a safer car without sacrificing ride quality. Thats the way I'm going....that and a nice tint job, but thats a different thread isnt it?

[CtrlAltDefeat]

Originally Posted by sickpuppy1

Now from a "practical" point of view, the Swaybar is good sense, in that a more nuetral car is a safer car without sacrificing ride quality. Thats the way I'm going....that and a nice tint job, but thats a different thread isnt it?

tint job?

not sure what you are referring to.. (i commented with pics on a tint thread earlier did i goof up? I dont see any thing...)

also... a sway bar causes less under-steer, which is the opposite of safer...

Originally Posted by Loren

If anything, adding or increasing the size of a rear swaybar (or otherwise increasing rear roll stiffness in any way) will tend to make the back end of the car "step out" (oversteer) more in a turn, not less. Remember, a rear swaybar is transferring weight from the outside rear tire to the inside front, it's giving you LESS grip in the rear... but that's generally not a problem in a FWD car.

Originally Posted by Loren

Without the bar, you FEEL like the rear is going to kick out because of all the body roll back there.

But, in reality, the back end is ACTUALLY more likely to kick out with the rear bar in place. That's an important thing to be aware of. It's one of the downsides of big swaybars. They increase confidence by reducing body roll and making the car FEEL better... but, at the limit, they often have effects that the driver doesn't realize... until it's too late. They make the car less forgiving to big driver errors.

Find a safe place to push the limits of your car and learn what it's going to do! (even if your car is completely stock)

[CtrlAltDefeat]

also:

Originally Posted by Loren

Automotive design and engineering is all about compromises. The general public, especially the "commuter car" market, wants a car that is comfortable and handles predictably. Basically, they want an appliance. A couch that they can drive to work.

For these reasons, cars like the Yaris are designed with fairly soft suspension that handles most road conditions "comfortably" and the car is designed to handle predictably and safely. Predictable and safe handling for the average idiot driver means understeer.

Enter the rear swaybar. A rear swaybar's purpose is to increase rear roll stiffness. Increasing rear roll stiffness has a lot of effects, but the most obvious is a reduction in body roll and an improvement in steering response, which the "performance-minded" driver likes... but the general public might actually prefer the car to be less "twitchy" and prefer a little body roll that allows the suspension to lean in a turn instead of making THEM lean in a turn.

Increasing rear roll stiffness also changes the handling bias of the car and makes it less prone to understeer, or more prone to oversteer. The stiffer the rear of the car is made, the more likely it is to oversteer in an emergency maneuver. Toyota doesn't want the liability of putting the average idiot in a car that could oversteer unexpectedly, so they design their cars to understeer predictably.

Now, if Toyota wanted the rear roll stiffness to be greater on the Yaris... they wouldn't have fit a swaybar to it, anyway. It adds weight, complexity and expense, things that are considered greatly in the design of such a car. Even if they used the TRD/Ultra Racing design (a beam axle reinforcement rather than a true anti-sway bar), it would still add at least 7 parts to the car, one of them being a bar that requires complex forming and welding and heat-treating, the others being a pair of bolts, nuts and washers. (if they put a REAL swaybar on the car, the part count would be at least 3 times as many with brackets, end links, bushings, etc.) No, if Toyota wanted to add more stiffness to the back of the Yaris, they would simply have designed a stiffer beam axle assembly that allowed less twist or they would have fitted stiffer rear springs... either of which would create a compromise to the level of comfort that the car was designed for.

all of this is from my sway bar install thread...

[eht13]

Originally Posted by CtrlAltDefeat

all of this is from my sway bar install thread...

Thanks. Could you provide a link to that thread?

[tk-421]

Originally Posted by eht13

Thanks. Could you provide a link to that thread?

http://www.yarisworld.com/forums/showthread.php?t=17087

[CtrlAltDefeat]

Originally Posted by tk-421

http://www.yarisworld.com/forums/showthread.php?t=17087

Thanks tk

[eht13]

Thanks.

[CtrlAltDefeat]

well the wheelbase is like 3.5 inches longer on the sedan, so I cant imagine that would affect it much. according to my limited knowledge, body roll is a product of the stiffness of the suspension along with things like sway bars. springs will give you a stiffer suspension, causing less compression of the suspension on the side of the car on the outside of the turn. The sway bar transfers force to the opposite side of the car, by physically linking them.

Under-steer is where you have to turn the wheel further then the angle of the turn you are making, because you are losing traction on the turning wheels (common on fwd cars, since both acceleration and turning has to happen with the same set of wheels)

Of course I am a relative noob, so this is just what I've gathered from the little experience I've had. If I am wrong, I hope someone else will enlighten both of us :D

[Loren]

"Better" is an interesting concept. You're not driving anywhere near the limits of the car as it sits. What's the point of "better" in that instance?

It's like having a car that is capable of accelerating from 0-60 in 6 second, but NEVER doing so. Instead, you drive it gingerly, accelerating at the typical pace of traffic. "Better" would be to modify it to make more power and be capable of accelerating to 60 mph in 4.5 seconds... but WHY?

Honestly, your best course of action: Invest in a kick-ass set of performance tires. There are no downsides to that, and unlike suspension changes, they'll also help the car to STOP better when you need it to.

[eht13]

Good point, but not sure how to know it's nowhere near the limits now. As I said, I think I have pushed it near "the limits" on curves (based on speed and the tightness of the turn)... but just that I still felt in control and that understeer didn't seem to be an issue. Thanks for the idea about better tires too.

As far as the downsides you mentioned... do you think swar bars' main downside is the potential to cause oversteer when unexpected? And how about the downsides of lowering springs in comparison? Thanks again.

[detroiter]

You know your pushing the car to the limits when you hear the tires squeeling and begging for mercy :)


And you can avoid oversteer. It's called don't turn hard and sharp while going as fast as you shouldn't be.

[Loren]

If you want to learn the limits of your car, the street isn't the place to do it. Search for autocross events in your area.

[eht13]

^ Definitely. Just wanted to clarify my driving experience so far, and ask those other questions regarding relative downsides. Thanks.

[Loren]

It's like this: The typical driver in an emergency situation tends to panic and over-react. If they try to make an evasive maneuver, they do it too hard. If they try to slow down, they slam their foot to the floor (and lock up the brakes if they don't have ABS). Cars are designed for this behavior. They are designed to keep the car pointed in the right direction as much as possible, even in those awkward situations where the driver has done something stupid.

Adding a rear swaybar to your Yaris removes some of that protection and puts the burden of "not being stupid" on you. If you continue to drive like the "typical driver", you'll be much more likely to lose control of the car due to something like trying to execute a overly-exuberant turn while braking with all your might. If you have your wits about you and know NOT to do that sort of thing, there is absolutely no downside at all to adding a rear swaybar.

In short, there's a reason the car didn't come that way from the factory. But, also bear in mind that TRD wouldn't offer a part that was going to make your car unsafe to drive. It's not like the TRD rear bar is going to suddenly make your car undriveable or anything... just slightly less idiot-proof.

[eht13]

Makes sense... thanks!