Swaybar vs. lowering springs

[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.

[eht13]

OK... I just read that thread, and found it very informative. A lot of knowledge here. The problem is, this is one of those situations where the more you learn, the more you're confused.

I do not autox or anything... just regular road driving, although I enjoy pretty "spirited" driving when conditions are safe for it.

I'm not sure if the amount of body roll I feel when cornering is enough to make it worth getting a rear sway bar; it doesn't bother me, but I don't know if I'm used to it or not. I think I have pushed it near "the limits" on curves, but it hasn't felt like it was understeering to me... and I feel in control through those corners. This is probably totally irrelevant, but could the longer wheelbase of the sedan vs. the hatchback mean that understeer and roll could be less pronounced in the sedan?

[Loren]

Originally Posted by eht13

I think I have pushed it near "the limits" on curves, but it hasn't felt like it was understeering to me... and I feel in control through those corners.

If it ain't broke, don't fix it.

If you're happy with how your car handles, why change anything?