Sway bar vs Stiffer Springs

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Hi.
I had discussed it previously (may be in this or other forums)..
After buying W163 ML320, i realized that was side to side rocking, even with new Bilstein shocks, over bumps and patholes. Guys other forums suggested deleting rear sway bar may be helpful. It may be paradox, that if sway bar intended to prevent sway, how it can cause sway ? But it was true.
I removed both for testing, The car is now unbelievable comfortable, and almost 0 rocking over deep holes and high bumps.
İt feels like as if car is going over the pillow. Of course at the corners it is extremely bad, so i will reinstall front bar. Please correct if i am wrong,
It is pretty obvious how sway bar prevents car from rolling over. it acts like a spring, and makes it difficult for wheels to articulate independently.
However stiffer springs does the same too.
So if i install stiffer springs (torsion bars) the car will be more stable at corners, just like with the sway bar.
So is there any advantage of sway bars over stiffer springs ?
i will post video of car going over same bumps, both before and after sway bar removal.
 
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What is your purpose: sounds like this is for rough roads, not high performance on smooth roads?
For rough road and off-road applications, removing the sway bars entirely helps the wheels move independently over bumps, which improves ride quality and traction. Yet this of course allows a lot of body roll in turns.
If you want to reduce body roll without impairing independent wheel action, you can use soft (smaller diameter) swaybars, or higher spring rates. Which works better depends on the vehicle and its dynamics.
 

NICAT

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Stiffer springs will be harder all the time where a sway bar only enters the picture in turns.

Your stiffer Bilsteins are talking to each other through the sway bar.

Sway bars are always active when wheels want to articulate inependently. Arent they ? :)

What is your purpose: sounds like this is for rough roads, not high performance on smooth roads?
If you want to reduce body roll without impairing independent wheel action, you can use soft (smaller diameter) swaybars, or higher spring rates. Which works better depends on the vehicle and its dynamics.

Yes, for body rough roads.
Seeminly there is no way to achieve both at the same time, prevent body roll and have comfortable ride at rough roads :)
Only some advanced technologies can help. Audi has feature that if it feels body roll, it stiffens sway bar automatically.
 
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I had discussed it previously (may be in this or other forums)..

You actually have issues even finding your own threads?

 

NICAT

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You actually have issues even finding your own threads?

Oh yes, That is right.
 
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Hi.
I had discussed it previously (may be in this or other forums)..
After buying W163 ML320, i realized that was side to side rocking, even with new Bilstein shocks, over bumps and patholes. Guys other forums suggested deleting rear sway bar may be helpful. It may be paradox, that if sway bar intended to prevent sway, how it can cause sway ? But it was true.
I removed both for testing, The car is now unbelievable comfortable, and almost 0 rocking over deep holes and high bumps.
İt feels like as if car is going over the pillow. Of course at the corners it is extremely bad, so i will reinstall front bar. Please correct if i am wrong,
It is pretty obvious how sway bar prevents car from rolling over. it acts like a spring, and makes it difficult for wheels to articulate independently.
However stiffer springs does the same too.
So if i install stiffer springs (torsion bars) the car will be more stable at corners, just like with the sway bar.
So is there any advantage of sway bars over stiffer springs ?
i will post video of car going over same bumps, both before and after sway bar removal.

Yes, sway bars ONLY affect side to side motions while stiffer springs affect every up and down motion. As bad as the sway bars are, the same roll stiffnes with stiffer springs is worse for comfort.
 
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Having lived with a base model 1966 Chevy Biscayne, with no sway bars at all, I will verify that it's a smooth ride on rough roads.
But on the highway, it's a queasy nightmare. We don't realize what a favor sway bars do us by squashing side-to-side motions on the car's short axis. Take your car up to 70 on a smooth road before you make any rash decisions.
 
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Because sway bars connect both sides of the suspension together, the bigger they are, the more they act like a solid axle. So when one side hits a bump, it can kind of pitch the car, which is what you're feeling.

Your problem is improperly valved dampers (shocks). I know that may sound strange given that bilstein spec'd them out for your car, but they simply might not suit your preferred feel. The only real solution to your problem without compromising cornering is different dampers. In fact, stiffer springs and matched dampers might actually eliminate the feeling you're getting when you go over bumps because body movement will be better controlled in general.
 
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I see people mention the solid axle when referencing sway bars but it's nothing like that. You do realise solid axle cars also come with sway bars?

His issue is that there's excessive weight transfer from unloading one wheel. Stiffer springs will do the same ultimately
 
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I see people mention the solid axle when referencing sway bars but it's nothing like that. You do realise solid axle cars also come with sway bars?

His issue is that there's excessive weight transfer from unloading one wheel. Stiffer springs will do the same ultimately
Except it actually is. The bigger the sway bar, the more the suspension acts like a traditional solid axle. Yeah, solid axle cars still need roll control, but what we're referencing is the car pitching over one-sided bumps, as one side has to affect the other, unlike an independent suspension. If you took a solid 3in steel bar and connected both sides of the independent suspension with it, what do you think would happen when one side hit a pothole?

This is why rally cars often drop their sway bars in gravel stages. They don't need the roll control, but they do need the independent control of each wheel over bumps.
 
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Most likely the issue originates due to the excessive weight in the roof of an SUV. All of these other efforts are done to try to compensate for that top heaviness.
 
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Except it actually is. The bigger the sway bar, the more the suspension acts like a traditional solid axle. Yeah, solid axle cars still need roll control, but what we're referencing is the car pitching over one-sided bumps, as one side has to affect the other, unlike an independent suspension. If you took a solid 3in steel bar and connected both sides of the independent suspension with it, what do you think would happen when one side hit a pothole?

This is why rally cars often drop their sway bars in gravel stages. They don't need the roll control, but they do need the independent control of each wheel over bumps.

Independent suspension cars twitch also, if you change the load on one wheel it affects the 3 others aswell.

sway bars don't help at all on rough surfaces, they make things worse, nothing to do with suspension setup. The increased wheel travel without sway bars is definitely a plus too.
 
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Independent suspension cars twitch also, if you change the load on one wheel it affects the 3 others aswell.

sway bars don't help at all on rough surfaces, they make things worse, nothing to do with suspension setup. The increased wheel travel without sway bars is definitely a plus too.
As the Director of Sales for a sway bar company I can't tell you how many times I hear the myth of a sway bar limiting wheel travel....
 

NICAT

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As the Director of Sales for a sway bar company I can't tell you how many times I hear the myth of a sway bar limiting wheel travel....

Myth?
Isn't it basic physics sir ?
While 'sway bar limiting wheel travel' statement is too generic to be true.
More accurately, cant we say, 'Sway bar increase the amount of force required for wheel travel at one side of the car, if the wheel at the other side is not traveling or just is moving to the opposite direction?

 

AZjeff

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Technically anti-sway bars or anti-roll bars . The Jeep flexing example is true but isn't terribly valid for road going vehicles that aren't operating at extremes of suspension travel. A/S bars make the outside springs stiffer while preventing the inside spring from unloading by compressing the inside springs a calculated percentage based on length, thickness, length of the lever arms and probably other things unknown to me. The Jeep will be better off road but the driver will get a surprise if he forgets to re-engage it when he drives home.

We experimented with A/S bars on a 1/2 mile paved oval stock car. Driving at the limit the result of changes in only the A/S bar(s) is dramatic. You can get away with removing the bars from a street vehicle until you need to make a high speed emergency maneuver when you will likely loose control. Removing the rear only will cause the car to push like a barge when you increase speed & cornering force. It won't turn enough when you really want it to. Springs and bars are designed to work together to achieve desired handling characteristics, usually a mild push.

Heavier springs will make the ride harsher and could possibly cause the body to roll more because they're flexing less pushing the corner up.

To the OP, do other owners of this vehicle have the same complaint about the ride and what do they do about it? What speed is this happening?

One fix is to drive faster, at some speed the body will remain still while the suspension is doing all the work. Like Robby Gordon. (y)
 
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With a few exceptions, and extreme off road buggies being one of them, there are lots of other chassis parts (or frames) that are the limiting factor. Sway bars are spring steel, they are meant to twist, and they do. Watching the internet experts take the sway bars off a street car "because they limit wheel travel" is someone who is about to get a lesson in corning forces and vehicle dynamics. You can use sway bars to tune a suspension to such a great degree, and even within the company there are discussions on bigger bar vs small bar, tubular vs solid, among other things in each application.

On off-road and overland vehicles we hear "I gotta have a disconnect". I always wonder if you are serious about off-roading/overlanding why don't you have a locker or limited slip at the least. Suspension travel is great when off road, but it isn't then end all to getting where you want to go. You'd be surprised how many sway bar requests we get for purely off-road vehicles. I guess those guys don't read the forums.

Saying all that, everyone is free to do what they want, there are some suspension gurus out there that make it work without sway bars in a highly specialized suspension, but for 99% of the street cars out there, including Jeeps and other high center of gravity vehicles, that sway bar is going to make the driving experience all the better....
 
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Heavier springs will make the ride harsher and could possibly cause the body to roll more because they're flexing less pushing the corner up.
The rest of your post is good, but this is just silly. It's not possible for higher rate springs to cause more body roll. More body movement when hitting a large bump? Sure, something like a speed bump or something, especially with an improperly valved damper. More body roll? Never.
Independent suspension cars twitch also, if you change the load on one wheel it affects the 3 others aswell.

sway bars don't help at all on rough surfaces, they make things worse, nothing to do with suspension setup. The increased wheel travel without sway bars is definitely a plus too.
So, you're agreeing with me now? Sway bars are part of suspension setup, so the way you're phrasing that makes no sense.
As the Director of Sales for a sway bar company I can't tell you how many times I hear the myth of a sway bar limiting wheel travel....
Except that it's a fact. Very common on autocross cars with too soft of springs and big bars to lift the rear inside wheel while cornering, hurting traction. Removing the rear bar is a bandaid that usually makes the car push, but still run a faster time because traction (at least on rwd/awd cars).
 

AZjeff

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The rest of your post is good, but this is just silly. It's not possible for higher rate springs to cause more body roll. More body movement when hitting a large bump? Sure, something like a speed bump or something, especially with an improperly valved damper. More body roll? Never.

Agreed I worded it poorly. I was thinking of driving moderately on a rough road where suspension isn't flexing much and making the roll that the OP doesn't like.

You have autocross experience, guess what happens when you put a rear bar on an oval track stock car that was set up without one?

Drift car.
 
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