Soft Springs. Hard swaybars

[Redlined]

I remember reading an artical in an old hotrod magazine when I was a teen about running near stock springs with large swaybars for sporting handling without sacrificing tons of Ride quality.

Anyone tried anything like this or have input?

I want to make my Legacy corner flatter but I enjoy the supple ride. I was thinking with stock springs and struts + heavy roll bars and 16x6 rims/tires Ill get a good compromise.

[DLC]

It's true. You should either run small bars and heavy springs or big bars and soft springs, but not big bars and stiff springs.

[BAC5.2]

Depends. A big bar will easily overcome the soft springs and soft struts, wearing them out quickly.

[Redlined]

What would be a good combination for this that wont wipe out the struts?

[BAC5.2]

20mm maybe? The stock SS 18mm bars are a pretty nice upgrade from stock L bars.

[Redlined]

Sounds reasonable. I may just go with the SS bars

[biggreen96]

I dont understand how just a bigger bar can cause accelerated wear on struts.
by limiting roll wont it save the struts just a tiny bit.
I understand that increasing the spring rates wears stock struts faster, I experinced that first hand.

[BAC5.2]

Body roll doesn't mean weight transfer from side to side.

By limiting roll, you usually drive more aggressively, increasing the load on the suspension.

I should have been more clear. Big bars make you wear out stock struts faster.

Sway bars DO, however, effectively increase spring rate.

[ultrasonic]

Sway bars DO, however, effectively increase spring rate.

But only when cornering, right?

Or should I say only when the suspension is loaded asymmetrically. In a straight line, with both left and right struts compressing the same amount the sway bar is not doing anything.

[Subtle]

Compliant spring rates, firm bars and adjustable shocks is the way I'm going, but as I've been mentioning--on the latter -- deciding which make is becoming a difficult choice.

Don Nimi at PDM has done a lot of competition in the North West and as he says has installed about 200 sets of AGX and doesn't recommend them now.

Even when set soft - too stiff on the bump.

[jamal]

Sway bars DO, however, effectively increase spring rate.

But only when cornering, right?

Or should I say only when the suspension is loaded asymmetrically. In a straight line, with both left and right struts compressing the same amount the sway bar is not doing anything.

correct.

Limiting body roll keeps the tires flatter and increases the responsiveness of the car.

And swaybars are still springs, and the struts damp their motion.

The thing about swaybars is that they're the most efficient way to reduce bodyroll, and they don't make the ride too stiff. Really, you just don't want to go to one extreme. There's nothing wrong with increasing spring weight and swaybar size. Unproportionally stiff swaybars are going to make the car feel unsteady on uneven surfaces and wierd in transitions, while stiff springs are going to make the car uncomfortable. Going too stiff will also decrease tire contact with the road on bumps.

It also depends what you're going to be doing. The end goal is to keep the tire flat and on the road, while making the car balanced and responsive.

To do that, you'll set a body roll limit and have a desired roll stiffness for the car based on camber. Too much roll means too much negative camber is required to keep the tire flat in corners. Too much camber reduces straightline [braking] traction. From what I can tell with Subarus, you can't really get too much negative camber.

Then the the springs and swaybars are set up to achieve a certain overall roll stiffness. The swaybars are used to vary the relative front and rear roll stiffnesses. Hence why people say that throwing on a big swaybar is a band-aid.

As far as our cars go on the street, the bigger bars you can buy probably aren't going to be too bad as long as you keep them balanced and go up with the springs a bit. I wouldn't go for the huge 25mm auto-x specific bars, but I definitely want stiffer springs, bigger sways, and stiffer bushings, along with more camber, just for my street/road rally driving.

Currently I have 18mm front and rear bars with 224/185 lb/in springs. I would go over 350 lb/in if I had the appropriate dampers and over 22mm with bars and drive it on the street. I don't think that would be too much of either for on-road/track. If I wanted to rally/rallyx, everything would be softer.

Oh and I should mention that I don't entirely know what I'm talking about so don't take this too seriously.

[BAC5.2]

I disagree that sway bars are the most efficient way to control body roll.

I think sway bars are the most COST efficient way to control body roll.

The most efficient way to control body roll is to design the suspension around it. Body roll can be, geometrically, eliminated. The problem is, that for a street car in mass production, it's tough to do this because to make it handle perfectly for a 180lb driver, everything will get fucked up when 3 of his friends get in the car. It's horribly impractical to design body roll entirely out of a car designed to be used as a street vehicle.

Best thing about designing a car to have less roll, is that you can use softer dampers than you would if you strapped on a ridiculous sway bar. The ride turns out to be slightly more compliant, and still handle better.

For the most part, sway bars make the driver feel more comfortable. That is their significant handling impact.

Body roll does not mean weight transfer.

Oh, and lots of camber hurts acceleration traction too. And I'd run 8 to 10 kg/m springs and appropriate dampers and 22mm bars on the street too.

[THAWA]

Currently I have 18mm front and rear bars with 224/185 lb/in springs. I would go over 350 lb/in if I had the appropriate dampers and over 22mm with bars and drive it on the street. I don't think that would be too much of either for on-road/track. If I wanted to rally/rallyx, everything would be softer.

Tribeca front sway bar, it's cheap and huge, put it on. Actually I just want someone with an NA crossmember to try and fit it.

[scottzg]

what's wrong with body roll? It tells the driver where the weight of the car is. Best way to get rid of body roll imo is to lower the car's center of gravity, preferably not by lowering it.

[jamal]

what's wrong with body roll? It tells the driver where the weight of the car is. Best way to get rid of body roll imo is to lower the car's center of gravity, preferably not by lowering it.

the tires go into positive camber for one.

[scottzg]

suspension geometry adds negative camber on compression...

[THAWA]

To a point. jamal, tribeca front sway bar, put it on!

[BAC5.2]

suspension geometry adds negative camber on compression...

Depends on setup. Some McPherson Strut vehicles go positive on compression. "Saftey" feature.

What dia. is the Tribeca bar? 22mm?

[THAWA]

25/16 f/r

[jamal]

To a point. jamal, tribeca front sway bar, put it on!

heh. does anyone know if they even fit?


also I remember hearing that if you were to double the stiffness of swaybars versus doubling the stiffness of springs the swaybars are going to be more effective in increasing the roll stiffness.

[THAWA]

No, that's why someone needs to try it. I'd do it, but you need an NA crossmember. It's hella cheap, like 60 bucks or something from the dealer.

[jamal]

well something is clunking and I can't figure it out. It seems to be swaybar related but when I was under the car today everything seemed fine.

So maybe I should replace it anyway.

The Tribeca uses a modified Legacy chassis, right? Has anyone tried a newer Legacy front swaybar on a BC/BF?

[THAWA]

Perfect time to upgrade. Go order one!

[scottzg]

suspension geometry adds negative camber on compression...

Depends on setup. Some McPherson Strut vehicles go positive on compression. "Saftey" feature.

I have never ever seen a car where this was the case. It seems like the chassis pickup would have ground clearance issues. What car are you thinking of? I want to gawk.


25mm swaybar doesn't seem like a very good way to get it done on a street car.

[THAWA]

Go look at your own car. Whenever the suspension is in the bump phase the camber is becoming less negative, when it's in the droop phase, the camber is becoming more negative.

A big sway bar is good for our shitty suspension setup. The less one strut bumps the less positive that wheel becomes.