Sway Bars - How they work and how to choose the right size for your needs

[justin93gt]

Ive been reading this thread and also checking out the various bars. What is the best size bar for a daily driver? Ive read that the big bars are for racing and smaller are for daily, but what is a "big bar" be in size and a "small bar"?
PS. very helpfull

[Norm Peterson]

Ive been reading this thread and also checking out the various bars. What is the best size bar for a daily driver? Ive read that the big bars are for racing and smaller are for daily, but what is a "big bar" be in size and a "small bar"?
PS. very helpfull

For the variety of sizes that's available, "small" is the 12mm OE bar, and "large" is the 22mm Addco(?) piece (that's a bit too big for the OE bracketry).

As for the "best" size, that depends partly on the rates of your front and rear springs and partly on your own preferences in handling characteristics, roll control, and ride quality. There's likely a few other things, but those are the "biggies". What point within the range between base OE-level ride comfort and serious cornering-competition handling are you shooting for? And if competition is being considered, is it more like 30 - 50 mph 2nd gear autocross or 100 mph road course running?

Norm

[justin93gt]

no it sjust daily driving, but I go to school and to get to school I take a highway and theres a lot of turns and ones very very sharp. It has intrax on it...

[Hans[93GT]]

Get the 16mm bar from the 2000 Mazda 626

[Domino81]

You won't change your front sway bar. Trust me on that one, it's not removable unless you drop the entire front subframe, including lower control arms. Also, no one makes aftermarket front bars for the Probe. You don't need them. The car understeers heavily out of the box, adding a bigger front bar makes things worse.

I've heard of people changing to a MX-6 sb. I heard it's a touch smaller.

[deyan]

I've heard of people changing to a MX-6 sb. I heard it's a touch smaller.

base probe front swaybar is also smaller.

[neilh2o]

what size rear sway bar matches up with eibach lowering springs all around coupled with tokico blues (roughly 240 front spring stiffness?) ..as it is w/stock sway bars the Probes cornering/road handling performance is dramatically improved over stock springs/struts..

[Norm Peterson]

Mostly what sees to be happening with swapping the springs only is that the front tires benefit more from the slightly reduced amount of roll than the rears do. It looks like the Tokico springs not only maintain similar "flat ride" behavior - they also do not shift the front/rear distribution of lateral load transfer much either, both setups being about 61/39 (with 25.4 mm front and 12 mm rear bars assumed). Moving the rear bar size up by 4 mm makes the lateral load transfer distribution about 57/43. Definitely "looser", or at least "less push". Just for reference (and as a disclaimer, not intended as a general recommendation), that 22 mm piece would put the LLTD at 48/52.

Most design philosophies want the LLTD to be within a few percent of the weight distribution, with the front LLTD normally being a few points higher than the front weight % to help ensure a little at-the-limit understeer when car usage and driver capabilities are unknown. For example, some experienced autocrossers prefer a setup that's far too "loose" for a newbie driver to be using on the street.

Late edit - the bar sizes are from a 626. Slightly different PGT bar sizes will shift the specific numbers around a little, but won't change them relative to each other much.

Norm

[Hans[93GT]]

what size rear sway bar matches up with eibach lowering springs all around coupled with tokico blues (roughly 240 front spring stiffness?) ..as it is w/stock sway bars the Probes cornering/road handling performance is dramatically improved over stock springs/struts..

Again, it's all personal preference.............but I personally wouldn't recommend any bigger than 16mm regardless of your objective. Even hardcore racers would be better off using stiffer rear springs instead of using a really thick bar. Thick swaybars sacrifice traction over bumpy corners.