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'18 OB 2.5 Ltd, No Eyesight, No Nav
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Discussion Starter #1
Sure the sway bar improves street performance, but I am wondering how the famous sway bar modification affects performace of the OB on snow and ice.

I would have a hard time believing the effect is zero. I could readily believe the sway bar slightly improves or slightly degrades performance on snow and ice. Which is it?

After 20 years of driving on snow and ice, I feel like anything that hardens the link between the car and road degrades performance on snow and ice. It’s a different world out there.

Thoughts?
 

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'03 outback limited, '01 Outback Limited, '01 Legacy L wagon, '96 Legacy Brighton wagon
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This opinion is based on 40 years of racing design experience for asphalt and dirt, but the physics should be the same for ice, even if certain parameters are wildly different:

Yes - anything that speeds up the steering inputs to the contact patches will most likely reduce ultimate grip - for ultimate grip under such low-grip conditions as ice, you want your transients to be as smooth as possible both for ultimate traction, and for the driver to be able to feel when the limit is being approached.

However, changing the balance of the car to more neutral by the addition of a stiffer rear bar MAY increase the ultimate cornering capability by splitting the lateral loads more equally front and rear.

Way more to this than I've just stated.
 

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2016 Outback Premium 2.5 CVT w/EyeSight+SRVD
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Way more to this than I've just stated.
Yep. Another consideration is that changing the RSB ... like different tires or many other suspension mods ... shifts the vehicle's center position withing the VDC system's control envelope. Whether this shift is significant or not is unknowable without some pretty sophisticated testing. Consider that even the "wimpy" 19mm RSB is already twice as stiff in torsion as the OE 16mm bar.
 

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Brucey
'17 3.6
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Sure the sway bar improves street performance, but I am wondering how the infamous sway bar modification affects performace of the OB on snow and ice.

I would have a hard time believing the effect is zero. I could readily believe the sway bar slightly improves or slightly degrades performance on snow and ice. Which is it?

After 20 years of driving on snow and ice, I feel like anything that hardens the link between the car and road degrades performance on snow and ice. It’s a different world out there.

Thoughts?
No perceived change.

I drove through over a foot of fresh snow with a 19mm sway bar.


On ice (like a skating rink) it's possible it would make it more tail happy.

Beyond that it's likely no big change.
 

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Deep snow and ice are 2 different things. On ice you are relying solely on tire grip at the contact patch. On snow, a significant amount of grip comes from shearing the snow ( tread shear grip, where you are packing the snow into the tread voids and then shearing the packed snow), and the "plowing" of the snow (lateral plowing when cornering, and longitudinal plowing under braking). This is why you can usually stop faster in snow (especially deep snow) just by locking up the brakes than you can with the ABS pulsing them.
 

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Sure the sway bar improves street performance, but I am wondering how the infamous sway bar modification affects performace of the OB on snow and ice.

I would have a hard time believing the effect is zero. I could readily believe the sway bar slightly improves or slightly degrades performance on snow and ice. Which is it?

After 20 years of driving on snow and ice, I feel like anything that hardens the link between the car and road degrades performance on snow and ice. It’s a different world out there.

Thoughts?
AWD/FWD vehicles are prone to understeer. Bigger rear sway bars offset that behavior and tend to cause oversteer with the back end wanting to come around and meet the front coming out of corners. Not so desirable when driving on slippery roads.

Folks make unwise decisions daily based on what they read on the ole interweb...........
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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AWD/FWD vehicles are prone to understeer. Bigger rear sway bars offset that behavior and tend to cause oversteer with the back end wanting to come around and meet the front coming out of corners. Not so desirable when driving on slippery roads.

Folks make unwise decisions daily based on what they read on the ole interweb...........
Agred on point number #1.

However, making the blanket statement the upgrade is "unwise" is doing the un-informed the same dis-service, just in reverse.
 

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AWD/FWD vehicles are prone to understeer. Bigger rear sway bars offset that behavior and tend to cause oversteer with the back end wanting to come around and meet the front coming out of corners. Not so desirable when driving on slippery roads.

Folks make unwise decisions daily based on what they read on the ole interweb...........
I'd much rather have my car oversteer in the snow than understeer in the snow. So for me the sway bar improved the performance in the snow.

Also the sway bar reduces the overall body roll, when the body rolls, this can cause the car to lose traction because of the sudden shift in weight. So when you reduce body roll, you reduce that sudden shift in weight and increase traction.
 

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Agree with it being benign. Does the past few decades of hundreds of millions of vehicles show any significance? I don't think so.

But to split hairs, there are likely situations it helps, situations it hurts, and situations where it's equal.

Variables such as the physical characteristics of the snow/ice, grade of the road, speed, given response, weight distribution within the vehicle, height of the vehicle, what type of driving is being attempted (aggressive, offroad, accident avoidance, careful commuter), cornering or braking, loosing control or regaining control, tire capabilities...and more....it could help in some of those and hurt in others.

Attempting to put things in nice, curated, yes/no, black/white, easy packages is often too simplified to tell the whole story. That's probably the case here.
 

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Brucey
'17 3.6
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Agree with it being benign. Does the past few decades of hundreds of millions of vehicles show any significance? I don't think so.

But to split hairs, there are likely situations it helps, situations it hurts, and situations where it's equal.

Variables such as the physical characteristics of the snow/ice, grade of the road, speed, given response, weight distribution within the vehicle, height of the vehicle, what type of driving is being attempted (aggressive, offroad, accident avoidance, careful commuter), cornering or braking, loosing control or regaining control, tire capabilities...and more....it could help in some of those and hurt in others.

Attempting to put things in nice, curated, yes/no, black/white, easy packages is often too simplified to tell the whole story. That's probably the case here.
But...what's the point of having all this internet if it's not to devolve every argument, to remove every nuance, and to simplify everything into neatly and easily coded boxes?

How is it to survive if it can't answer a simple question like "is this good or bad?"

:wink2:
 

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Agree with it being benign. Does the past few decades of hundreds of millions of vehicles show any significance? I don't think so.

But to split hairs, there are likely situations it helps, situations it hurts, and situations where it's equal.

Variables such as the physical characteristics of the snow/ice, grade of the road, speed, given response, weight distribution within the vehicle, height of the vehicle, what type of driving is being attempted (aggressive, offroad, accident avoidance, careful commuter), cornering or braking, loosing control or regaining control, tire capabilities...and more....it could help in some of those and hurt in others.

Attempting to put things in nice, curated, yes/no, black/white, easy packages is often too simplified to tell the whole story. That's probably the case here.
LOL, why would go and introduce common sense to the conversation.

Subaru engineers most likely have a mound of test data that brought them to the conclusion of the best size sway bars to include on their vehicles. I'm still waiting on that mound of data that proves the Subaru engineers made a mistake. Most of what owners feel after the change is in their head.
 

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Also the sway bar reduces the overall body roll, when the body rolls, this can cause the car to lose traction because of the sudden shift in weight. So when you reduce body roll, you reduce that sudden shift in weight and increase traction.
Uh, no.

For any lateral load - cornering "G's" - the amount of weight shifted is solely determined by the center of gravity height and the track width - a simple lever arm calculation. Reducing the body roll, whether it be by stiffer bar or stiffer springs does nothing to affect how much gets shifted, but does indeed affect how fast it gets there and how it is distributed to the front and rear tires, in turn affecting grip levels.
 

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2016 3.6 Limited with ES
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Most of what owners feel after the change is in their head.
Unless you've driven the car before and after changing the RSB I respectfully think you're full of poo.

Too many testimonials of people saying the car tracks flatter, doesn't get blown around nearly as much and then you have Brucey's vid on RSBs which was not subjective to discount the collective group having a placebo effect.

Subie picks the performance envelope of anticipated use but not all of us are at the same X and Y coordinates even our use is with the envelope.
 

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Subaru engineers most likely have a mound of test data that brought them to the conclusion of the best size sway bars to include on their vehicles. I'm still waiting on that mound of data that proves the Subaru engineers made a mistake. Most of what owners feel after the change is in their head.
The Sub engineers will have selected components like bar sizes based on what the marketing people want the cars to feel like to the customer, with a certain amount of push (understeer) being present at all times for safety reasons - the vast majority of drivers do not know how to handle a loose ( oversteer) car, so for liability reasons, they set the car up to push.
 

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Brucey
'17 3.6
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Too many testimonials of people saying the car tracks flatter, doesn't get blown around nearly as much and then you have Brucey's vid on RSBs which was not subjective to discount the collective group having a placebo effect.

Subie picks the performance envelope of anticipated use but not all of us are at the same X and Y coordinates even our use is with the envelope.
If enough people think something is true then it is true though. Think about how many people think "I can see Russia from my house." was said by the actual person and not by a different person parodying them.

Another example: I don't remember making a video on rear sway bars.

:wink2:
 

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Subaru with all the models seem to focus on retaining tire contact with the ground for as long as possible under hard handling. A big part of that is a flexible suspension. As you stiffen up the suspension you affect how the tires lift off under hard handling conditions. The Legacy and the OB prior to the cvt and the WRX manuals all have been prone to the tail coming around especially when lifying off the throttle further enhancing the tail chasing the front effect.

Many WRXs even on dry pavement have been wrecked by this enhanced effect of letting off the throttle which most drivers do out of reaction to getting into a turn way too fast for comfort. Trained drivers ie rally types etc all do the opposite adding power and using that to pull the car through a sharp turn.

Yes even my non turbo 2.5 Legacy GT 5spd on dry pavement would drift the rear end on a sudden throttle lift in a sweeping turn the first time you experience it is a bit of a spooky one. If your quick thinking even just light throttle steps the rear end back in line like nothing happened. If you do the opposite further reduce power or worse touch the brake your tail is going to pass your nose before you realize your mistake.

Add reduced traction conditions like snow, ice less than ideal tire tread oh and stiffer swaybar and you find out much sooner how quickly the tail trades places with the nose. The cvt cars are far less prone to this for a number of reasons, throttle response on lift off is muted far less sudden, thd cvt moves power / loading back to front far quicker and today the brake vectoring stability system tweeks brake drag at each corner to keep the car from swaping ends.

So newer Subarus stiffer sway might not matter that much except possibly impacting traction some and triggering earlier intervention by the stability systems. The older Subarus simply just stuffed you into a Krail sooner.
 

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2016 3.6 Limited with ES
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If enough people think something is true then it is true though. Think about how many people think "I can see Russia from my house." was said by the actual person and not by a different person parodying them.

Another example: I don't remember making a video on rear sway bars.

:wink2:
Don't confuse me with facts. Didn't you do a vid driving your car on blocks showing how far a single tire was off the ground which demonstrated flex?

If you didn't you should have.

So there.
 

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Brucey
'17 3.6
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Don't confuse me with facts. Didn't you do a vid driving your car on blocks showing how far a single tire was off the ground which demonstrated flex?

If you didn't you should have.

So there.
I took pictures yes but didn't have any video of it.

0:)
 

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I took pictures yes but didn't have any video of it.

0:)
My recollection was stunted, with the demons you brought, by the ES demo and hitting various items. It was the Chuckie like laugh hitting the last thing that forever torments me.
 
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The Sub engineers will have selected components like bar sizes based on what the marketing people want the cars to feel like to the customer, with a certain amount of push (understeer) being present at all times for safety reasons - the vast majority of drivers do not know how to handle a loose ( oversteer) car, so for liability reasons, they set the car up to push.
Exactly my point. Many make that change without a clue to the possible consequences. Most have probably never experienced oversteer in their lives.
They only know some Joe Isuzu on a Subaru forum posted it was the most beneficial change they could make.
 
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