Rambling thoughts on sways and springs by Clint

**Turninconcepts.com** · 03-30-2006, 11:05 AM

Since I seem to be asked these questions over and over I thought I would post my thoughts here to help folks out. It’s written in a flow of conscious manner so it might jump around a bit – sorry.

I would like to go over sway bars and springs for a bit, and give my thoughts and philosophies upon them.

First up is sway bars which transitions us to springs -

Front sway bar – why bigger is better
Our cars are set up with a McPherson setup up front. Like all suspension systems on cars they have their plusses and minuses. Some of the plusses for the McP setup are weight, and simplicity. The big con, that concerns us and front sways address, is poor dynamic camber curve.

See, what happens is this – when you compress the outside front corner (the one that’s loaded when in a turn) the suspension compresses as it should. When it compresses the dynamic camber curve causes the wheel to roll more toward positive camber. Push more and the more it rolls toward positive. This is bad because you start to loose grip as the inside edge of the tire gets “light.” Ideally you want the full contact patch evenly on the ground (or close to evenly) to maximize grip. This is the reason that folks try to run a decent amount of static negative camber. In other words, if you start with negative camber when it rolls over toward positive camber you have enough of a camber “budget” to allow for more contact patch on the ground.

So, where do bigger front bars come into play? Well, the front bar acts as a spring (torsion spring in this case) to help hold the static camber curve as you compress the front suspension. As you compress the loaded corner the bigger bar will resist that camber roll over to positive on the loaded corner. This is why bigger is better.

Ok, so what size should I use? Well, it really depends upon what you want to do. My thoughts are this – HUGE bars (i.e. The strano 32mm bar or the whiteline 27-29mm bar) make for every quick turn in, but darty handling. The moderately huge bars (i.e. Whiteline 24-26mm bar) make for very good turn in, but not so darty so things are smoother, more predictable and more controllable.

Hey, that’s great Clint, but still what bar should I get? These have been my suggestions to folks:

For autocross or somewhere where you want stupidly quick turning that is a bit darty then I suggest the HUGE bars.
For something like canyon driving or street only use (or track work with nothing but nice sweeping turns) I suggest something like the 24-26mm adjustable bar.

Rear Sway bar – why getting the biggest bar you can may not be the right solution:
Yes, it is true that a larger rear sway will increase oversteer, BUT there is a point of diminishing returns. If you go too big you will overpower the capabilities of the springs, and you will get inside rear wheel lift on hard turns at the worst possible time – at the apex. This means you won’t be able to get back on the gas until the tire in the air gets back on the ground. Sure, our cars have all sorts of trick LSDs, but they do not provide enough of a locking factor to account for a wheel in the air. Having a wheel in the air WILL hurt your handling (although it does look kinda cool).

So, how big should I go?
My suggestions are these
If you are on the stock springs then go with the 22mm adjustable whiteline bar. You can put it on the middle setting, but if you go to the stiffest setting you will start to see wheel lift.
If you are on pinks, gf210s or something that is an upgrade in springs, but you’re still using the stock struts then the 24mm setting on the bar and a little stiffer will be fine.

Ok Clint, what if I get coilovers or super stiff springs? Then I can run the biggest bar in the world, and be cool right?
Well, you could, but you reach a point of diminishing returns with sway bars. Remember springs affect both ride and roll. If you go with really stiff springs you will not need as much rear bar. The reason is because the really stiff springs will now provide that roll stiffness that you want. In fact, with really stiff springs you could easily find yourself needing to soften the rear bar. Keep that in mind.

General thoughts on oversteer and understeer -
I’ve said this to folks before, but I want to emphasize it here. Increasing oversteer is not the same and decreasing understeer. Sure the car may rotate, and you feel like you have less understeer, but think about it.

If you decrease understeer you do not necessarily have to increase oversteer. You’re just reducing the car’s front end tendency to plow to the outside of the turn. The rear end can and will follow quite nicely without pulling off “el drifto magnifico” moves.

If you increase oversteer you’re getting the rear of the car to try and come around more, but the front may still very well be plowing. Yes, you can meet and exceed the equilibrium of oversteer vs. understeer so that you’re hanging the back out faster than the front plows, but that’s not the best way to do it (unless you’re into drifting). Think of your traction circle – in that situation you’re using up more grip than you have available at both ends of the car, and you’re going to need some there for handling, braking, accelerating, and any other thing you need to call on the tires to do. In other words, you’re in a “hold on and we’ll see where she goes” situation and chances are you don’t want to be there.

In regards to sway bar brands –
Hey Clint, you sure seem to talk up whiteline a lot. What about other brands?
The reason I cite whiteline bars as examples is because those are the bars I am most familiar with. This is because we sell them. We don’t (at this time) sell any others. I am NOT saying the others suck, and whiteline is the shiz. Just that those are the ones I am most familiar with. I have worked on and driven a number of cars with other brand bars on them, and all the popular name brand bars are very good bars. If they weren’t very good then they wouldn’t be popular.

***wdb*** · 03-30-2006, 11:35 AM

Very nice! I take it that this is chapter one of several?

bluscooby23 · 03-30-2006, 11:40 AM

Very informative post. Thanks.

**Turninconcepts.com** · 03-30-2006, 12:05 PM

Quote:

Originally Posted by wdb

Very nice! I take it that this is chapter one of several?

We'll see. I just seem to by typing this quite a bit lately, and I figured it would be easier and more informative to post it.

lokutus1 · 03-30-2006, 12:42 PM

great info as always clint!!

Jas0nn · 03-30-2006, 12:59 PM

Quote:

See, what happens is this – when you compress the outside front corner (the one that’s loaded when in a turn)

quick question: can you explain why the load goes to the front outside corner during a turn?? to me this seems counterintuitive, but im sure theres an explanation. nicely written, by the way.

***JPWEraser*** · 03-30-2006, 01:00 PM

Thanks for taking the time to post that info, Clint. Good stuff.

**Turninconcepts.com** · 03-30-2006, 01:20 PM

Quote:

Originally Posted by Jas0nn

quick question: can you explain why the load goes to the front outside corner during a turn?? to me this seems counterintuitive, but im sure theres an explanation. nicely written, by the way.

it doesn't ALL go to the front corner. The weight shifts to the outside affecting both front and rear, but it's the front that is more adversely affected by suspension compression.

You will see changes from front to rear though if you are braking super late while also turning or braking early, and accelerating into the turn.

this is my understanding of ideal turn execution. Others will argue that there are better ways to handle a corner, and I whole heartedly agree, but it also depends on the corner as to what technique you use. I'm trying to be as generic as possible.

Approach corner at speed
Brake down to proper corner entry speed
off brake and back on gas lightly to maintain a constant speed while beginning turn in
apex (since we're AWD we can actually start to accelerate earlier in the apex point so you might even start this JUST before entering apex)
acccelerate out while smoothly/natural return to straight

spazegun2213 · 03-30-2006, 01:25 PM

clint,
you all rock! thanks for giving a more in depth explination on this as its something i want to know before touching the suspension. Going fast is the easy part (IMO) its all this turning stuff that gets complex

thanks!

Jas0nn · 03-30-2006, 01:26 PM

makes sense, i was confusing the inside and outside corner. when you said load, for some reason i thought that the load would be on the inside corner, but given suspension compression, its obvious the opposite is true. gracias.

o2sys · 03-31-2006, 07:23 AM

great info as always so which swaybar upgrade do you recommend first? to go with fronts first or rear? i see most ppl go with rear first...

KiNgMaRtY · 03-31-2006, 09:23 AM

Thanks for the info as I am still trying to see which bars are for me. Also hollow and non-hollow bars are very different for the sizeing

RacerXS · 03-31-2006, 09:58 AM

Nice write up.

T3h_Clap · 03-31-2006, 01:51 PM

very well thought out ramblings.

i like the part about reducing understeer.

o2sys · 04-02-2006, 01:11 PM

bump for my question

03-30-2006, 11:05 AM	#1
Turninconcepts.com Authorized Vendor Car: 04/08STI 95SVX 86E30 Posts: 5,034 Join Date: Jul 2003 Trader Rating: (53)	Rambling thoughts on sways and springs by Clint Since I seem to be asked these questions over and over I thought I would post my thoughts here to help folks out. It’s written in a flow of conscious manner so it might jump around a bit – sorry. I would like to go over sway bars and springs for a bit, and give my thoughts and philosophies upon them. First up is sway bars which transitions us to springs - Front sway bar – why bigger is better Our cars are set up with a McPherson setup up front. Like all suspension systems on cars they have their plusses and minuses. Some of the plusses for the McP setup are weight, and simplicity. The big con, that concerns us and front sways address, is poor dynamic camber curve. See, what happens is this – when you compress the outside front corner (the one that’s loaded when in a turn) the suspension compresses as it should. When it compresses the dynamic camber curve causes the wheel to roll more toward positive camber. Push more and the more it rolls toward positive. This is bad because you start to loose grip as the inside edge of the tire gets “light.” Ideally you want the full contact patch evenly on the ground (or close to evenly) to maximize grip. This is the reason that folks try to run a decent amount of static negative camber. In other words, if you start with negative camber when it rolls over toward positive camber you have enough of a camber “budget” to allow for more contact patch on the ground. So, where do bigger front bars come into play? Well, the front bar acts as a spring (torsion spring in this case) to help hold the static camber curve as you compress the front suspension. As you compress the loaded corner the bigger bar will resist that camber roll over to positive on the loaded corner. This is why bigger is better. Ok, so what size should I use? Well, it really depends upon what you want to do. My thoughts are this – HUGE bars (i.e. The strano 32mm bar or the whiteline 27-29mm bar) make for every quick turn in, but darty handling. The moderately huge bars (i.e. Whiteline 24-26mm bar) make for very good turn in, but not so darty so things are smoother, more predictable and more controllable. Hey, that’s great Clint, but still what bar should I get? These have been my suggestions to folks: For autocross or somewhere where you want stupidly quick turning that is a bit darty then I suggest the HUGE bars. For something like canyon driving or street only use (or track work with nothing but nice sweeping turns) I suggest something like the 24-26mm adjustable bar. Rear Sway bar – why getting the biggest bar you can may not be the right solution: Yes, it is true that a larger rear sway will increase oversteer, BUT there is a point of diminishing returns. If you go too big you will overpower the capabilities of the springs, and you will get inside rear wheel lift on hard turns at the worst possible time – at the apex. This means you won’t be able to get back on the gas until the tire in the air gets back on the ground. Sure, our cars have all sorts of trick LSDs, but they do not provide enough of a locking factor to account for a wheel in the air. Having a wheel in the air WILL hurt your handling (although it does look kinda cool). So, how big should I go? My suggestions are these If you are on the stock springs then go with the 22mm adjustable whiteline bar. You can put it on the middle setting, but if you go to the stiffest setting you will start to see wheel lift. If you are on pinks, gf210s or something that is an upgrade in springs, but you’re still using the stock struts then the 24mm setting on the bar and a little stiffer will be fine. Ok Clint, what if I get coilovers or super stiff springs? Then I can run the biggest bar in the world, and be cool right? Well, you could, but you reach a point of diminishing returns with sway bars. Remember springs affect both ride and roll. If you go with really stiff springs you will not need as much rear bar. The reason is because the really stiff springs will now provide that roll stiffness that you want. In fact, with really stiff springs you could easily find yourself needing to soften the rear bar. Keep that in mind. General thoughts on oversteer and understeer - I’ve said this to folks before, but I want to emphasize it here. Increasing oversteer is not the same and decreasing understeer. Sure the car may rotate, and you feel like you have less understeer, but think about it. If you decrease understeer you do not necessarily have to increase oversteer. You’re just reducing the car’s front end tendency to plow to the outside of the turn. The rear end can and will follow quite nicely without pulling off “el drifto magnifico” moves. If you increase oversteer you’re getting the rear of the car to try and come around more, but the front may still very well be plowing. Yes, you can meet and exceed the equilibrium of oversteer vs. understeer so that you’re hanging the back out faster than the front plows, but that’s not the best way to do it (unless you’re into drifting). Think of your traction circle – in that situation you’re using up more grip than you have available at both ends of the car, and you’re going to need some there for handling, braking, accelerating, and any other thing you need to call on the tires to do. In other words, you’re in a “hold on and we’ll see where she goes” situation and chances are you don’t want to be there. In regards to sway bar brands – Hey Clint, you sure seem to talk up whiteline a lot. What about other brands? The reason I cite whiteline bars as examples is because those are the bars I am most familiar with. This is because we sell them. We don’t (at this time) sell any others. I am NOT saying the others suck, and whiteline is the shiz. Just that those are the ones I am most familiar with. I have worked on and driven a number of cars with other brand bars on them, and all the popular name brand bars are very good bars. If they weren’t very good then they wouldn’t be popular. This ad is not endorsed by this member. Please register or login to hide this ad.

04-02-2006, 01:11 PM	#15
o2sys The Next Petter Solberg Car: 200? WRX STI Fav Mod: Super EX/RM-01A Location: NYC Posts: 934 Join Date: Nov 2005 Trader Rating: (1)	bump for my question This ad is not endorsed by this member. Please register or login to hide this ad.

03-30-2006, 11:35 AM	#2
*wdb* dances with roads Car: 2005 CGM STi Posts: 5,066 Join Date: Apr 2005 Trader Rating: (8)	Very nice! I take it that this is chapter one of several?

03-30-2006, 11:40 AM	#3
bluscooby23 Amateur STI Driver Car: 01 RS Fav Mod: flux capacitor Location: NoVA Posts: 27 Join Date: Aug 2005 Trader Rating: (0)	Very informative post. Thanks.

03-30-2006, 12:42 PM	#5
lokutus1 Spec C Club Car: 05 WRB WRX STi Fav Mod: FYI, I'm a dude Location: Burlington, MA Posts: 2,349 Join Date: Mar 2005 Trader Rating: (10)	great info as always clint!!

03-30-2006, 01:00 PM	#7
*JPWEraser* Platinum Member Car: 05 STi Fav Mod: Do Luck CF Location: East TN Posts: 1,564 Join Date: May 2005 Trader Rating: (4)	Thanks for taking the time to post that info, Clint. Good stuff.

03-30-2006, 01:25 PM	#9
spazegun2213 Poor Speed Racer Car: 96 328 Fav Mod: Tightening the nut behind the wheel! Location: Northern VA Posts: 8,432 Join Date: Mar 2005 Trader Rating: (8)	clint, you all rock! thanks for giving a more in depth explination on this as its something i want to know before touching the suspension. Going fast is the easy part (IMO) its all this turning stuff that gets complex thanks!

03-30-2006, 01:26 PM	#10
Jas0nn Professional STI Racer Car: Dolphin Grey B6 S4 Fav Mod: i miss my sti Location: Westchester, New York Posts: 645 Join Date: Oct 2005 Trader Rating: (1)	makes sense, i was confusing the inside and outside corner. when you said load, for some reason i thought that the load would be on the inside corner, but given suspension compression, its obvious the opposite is true. gracias.

03-31-2006, 07:23 AM	#11
o2sys The Next Petter Solberg Car: 200? WRX STI Fav Mod: Super EX/RM-01A Location: NYC Posts: 934 Join Date: Nov 2005 Trader Rating: (1)	great info as always so which swaybar upgrade do you recommend first? to go with fronts first or rear? i see most ppl go with rear first...

03-31-2006, 09:23 AM	#12
KiNgMaRtY Spec C Club Car: 05 STI Fav Mod: Invidia N1-R Location: Anaheim, CA Posts: 1,310 Join Date: Sep 2004 Trader Rating: (5)	Thanks for the info as I am still trying to see which bars are for me. Also hollow and non-hollow bars are very different for the sizeing

03-31-2006, 09:58 AM	#13
RacerXS S204 Racer Car: 05' Sti Black Fav Mod: Dyslexia Location: Central, NJ Posts: 3,362 Join Date: Oct 2004 Trader Rating: (13)	Nice write up.

03-31-2006, 01:51 PM	#14
T3h_Clap Wheel33tist Whore Car: Aspen White GDF-D Fav Mod: Pastelito Racing / SFSOC Location: Orlando Posts: 21,310 Join Date: Dec 2004 Trader Rating: (5)	very well thought out ramblings. i like the part about reducing understeer.