beefier rear swaybar = more oversteer?

[rps13_fastback]

I've been searching for a while and it seems as if I'm getting 2 different answers. Most people have said that a beefier rear sway bar will make your car oversteer more (maintaining stock front sway bar) but I would think the opposite.

Wouldn't it cause your car to understeer more? I am thinking since there is less body roll in the rear and therefore more contact patch for the tires, the rear would have better grip than the front so the front won't be able to turn as quickly as the rear. If this is incorrect then please someone explain to me what happens =). Enlighten me please!

[Flybert]

Let me try to explain it this way. If you have a beefier bar in the rear, wouldn't there be more of a balanced weight distribution between the two rear wheels instead of one being heavy and the other being light. I'm thinking that with a smaller rear sway it would be harder to brake loose the wheel with more weight on it but I could be wrong.

[old_s13]

Increasing the stiffness of the rear sway bar will increase your car's ability to oversteer. Anytime you stiffen the rear, whether its by bumping up the tire pressure or by increasing the swaybar, shock, bushings, whatever -- it increases the car's ability for the rear to skip out.

- Mike

[Ghettokracker71]

Originally posted by old_s13
Increasing the stiffness of the rear sway bar will increase your car's ability to oversteer. Anytime you stiffen the rear, whether its by bumping up the tire pressure or by increasing the swaybar, shock, bushings, whatever -- it increases the car's ability for the rear to skip out.

- Mike

I don't know but...what S13 here said makes sence to me....

[Chernobyl]

Others have already covered the physics, so I will tell you from first-hand experience on an S14.

base stock s14 has no rear sway bar. hard to break the rear end loose, and the car understeered at the limit.

I installed just the ST rear swaybar first and drove it around. The car quit understeering and was very neutral handling. The rear end came out when wanted at this point. I loved the handling.

With both the ST bars on, the car returned back to its understeering self. Just with less body roll.

BTW, my understeer is mostly due to my 205/225 tire setup.


sooooo..... a stiffer rear bar will help transfer more of the grip to the front wheels in a corner while lowering rear grip a bit. this will cause oversteer in extreme cases.

[DSC]

http://www.howstuffworks.com/question432.htm

http://auto.howstuffworks.com/framed.htm?parent=question432.htm&url=http://www.tsimportedautomotive.com/Swabarra.html

A little more detail, thought I'm dissapointed in howstuffworks this time as they could have done much better.

http://www.seansa4page.com/resource/steering.html
http://www.grassrootsmotorsports.com/swaybars.html
http://www.wtrscca.org/tech.htm

Just to add to what old_s13 said, its correct except in a situation where your tire pressure is too low. In that case increasing pressure will increase grip...to a point, then it decreases it and does exactly as old_s13 said.

Just FYI, I have tried every possible comination of sway bars with none, stock front and rear, and whiteline front and rear using different settings. [using stock suspension]
It gives quite an apprication of what these things do...than and makes you feel bad for the base s14 owners as they are the only ones w/out front and rear sways :wtc:

[Doriftomodachi]

Originally posted by DSC
http://www.howstuffworks.com/question432.htm

http://auto.howstuffworks.com/framed.htm?parent=question432.htm&url=http://www.tsimportedautomotive.com/Swabarra.html

A little more detail, thought I'm dissapointed in howstuffworks this time as they could have done much better.

http://www.seansa4page.com/resource/steering.html
http://www.grassrootsmotorsports.com/swaybars.html
http://www.wtrscca.org/tech.htm

Just to add to what old_s13 said, its correct except in a situation where your tire pressure is too low. In that case increasing pressure will increase grip...to a point, then it decreases it and does exactly as old_s13 said.

Just FYI, I have tried every possible comination of sway bars with none, stock front and rear, and whiteline front and rear using different settings. [using stock suspension]
It gives quite an apprication of what these things do...than and makes you feel bad for the base s14 owners as they are the only ones w/out front and rear sways :wtc:

Actually the base s14's DO come with a front swaybar. They do not come with the rear one.

[DSC]

Ahh, yes, that is what I mean. Now that I reread it, I wasn't very clear. I was meaning to say it is the only model without both front and rear sway bars. I should have included that it DOES in fact come with the front sway stock. Thanks for the correction.

[vodka]

Here's a nice, basic guide about mod's effects on understeer & oversteer




ADJUSTMENT ........... TO INCREASE UNDERSTEER.................. TO INCREASE OVERSTEER


Front Anti-roll Bar .................. Increase bar diameter ........................................... Decrease bar diameter
Rear Anti-roll Bar ................... Decrease bar diameter ...........................................Increas e bar diameter
Weight Distribution ................. Move weight forward ............................................. Move weight rearward
Front Springs ............................ Stiffer .................................................. ................... Softer
Rear Springs ............................ Softer .................................................. .................... Stiffer
Front Wheel Camber ............... More positive .................................................. ...... More negative
Rear Wheel Camber ................ More negative .................................................. .... More positive
Front Caster ............................ More positive .................................................. ....... More negative
Front Tire Pressure ................. Decrease .................................................. .............. Increase
Rear Tire Pressure ................. Increase .................................................. ................ Decrease

[andrave]

it just transfers energy

a stiffer rear bar transfers what would be be body roll into the outside tire, which places a hire load on it compared to the inside tire. With a higher load on it, it will break lose more easily. Basically it places more lateral load onto the outside tire, which makes the rear end step out easier since it puts more weight on one tire.

[rps13_fastback]

Originally posted by old_s13
Increasing the stiffness of the rear sway bar will increase your car's ability to oversteer. Anytime you stiffen the rear, whether its by bumping up the tire pressure or by increasing the swaybar, shock, bushings, whatever -- it increases the car's ability for the rear to skip out.

- Mike

old_s13, you just said bumping up the rear tire pressure will increase oversteer? i was going over the list vodka posted and it says:

ADJUSTMENT ........... TO INCREASE UNDERSTEER.................. TO INCREASE OVERSTEER

Rear Tire Pressure ................. Increase .................................................. ................ Decrease

Or was that what DSC was talking about?

[holisticbeatz]

Install the rear sway bar and find out. The beauty of suspension components; anything you modify will give you instant feedback when driving.

[nightwalker]

so what would you guys recommend as far as sway bars go. I was thinking about the whitelines, but don't want to really mess with the adjusting, unless they are THAT much better.

How about the ST sway bars? I have an 89 240, and have been pondering either these or the Tanabes.

What are you experiences with the different bars guys? Please share if you have compared them. Thanks.

[Var]

Let me enlighten you. s13's have a horrible ass tendancy to understeer. that's probably why s14's never came with HICAS. They probably sorted out all the bullshit issues s13's have. The front end likes to plow into the ground. You'd better be off the gas if you're trying to turn in hella fast. Im running whiteline front & rear sway bars(soft front, stiff rear), front & rear cp-racing strut bars, poly bushings, autopower roll cage, 6.7k/4.5k Ground control w/AGX shocks, and the worst part is my Tein camber plates are maxed out at negative. After learning by trial and error tuning my suspension and paying careful attention to what mods to to the car, i've come to realize that i'm going to spend most future efforts into stiffening up the rear end of my car. I will try everything there is. Solid subframe, rear pillow ball mounts, rear pillar bar,rear lower tie bar if i can get it to fit. Then i think i'll be happy with the car's behavior. As for right now, my car grips mad around turns but the bottom line is it understeers at the worst times...especially on a fast turn-in.

[old_s13]

At the limit my car understeers, I personally dont mind it that much because its a nice safety net for driving fast and aggressively on the streets. While I DO enjoy oversteer, I personally think that a bit of understeer is nice because you can always use gas to induce oversteer.

I am sure as my skills get even better, I'll practice setting my car up for more natural oversteer.. but if I wanted that, I would get an MR2. I think right now I am pretty content with my car's suspensioin setup.

ps: Tires make, model, air pressure, size, and condition play a HUGE role also in the handling characteristics.. something to think about. Its not always as simple as the chart shown above, it can vary.

-m

[phrozen]

waiting for :bowdown: dousan to say something. haha that guy knows everything!

[thx247]

west, I know it sounds wack but consider again swapping those springs around. btw I appreciate the offer on smog test, I'll see what I can do with the car today.

I still have a 98 KA I could throw in.

[Brian]

my experience

base s14 - car handled well but understeered during corners

addition of cusco rear stabilizer bar and kept stock front bar - could feel the difference immediatly. rear is much tighter and oversteer is felt easily.

[Dousan_PG]

Originally posted by westboroughpimp
Let me enlighten you. s13's have a horrible ass tendancy to understeer. that's probably why s14's never came with HICAS. .

hey! your wrong

s14s DID come w/ HICAS

but only in Japan

[DSC]

Originally posted by andrave
it just transfers energy

a stiffer rear bar transfers what would be be body roll into the outside tire, which places a hire load on it compared to the inside tire. With a higher load on it, it will break lose more easily. Basically it places more lateral load onto the outside tire, which makes the rear end step out easier since it puts more weight on one tire.

Going by that theory, sway bars make your car slower. Your saying that by REDUCING roll with a stiffer sway bar you INCREASE the load on the OUTSIDE tire???

You can't look at it as what the part does to the car alone but the relationship between the front and rear. If the front can continue to roll but the rear cannot it starts to come around...I wish I knew enough to explain it in more detail.

From what I've seen a sway bar makes a car corner flatter using the inside tire more and allowing much quicker direction changes.

[old_s13]

I wont get into the technicalities, but I will say that having fat sway bars has increased my OVERALL handling performance, but mostly in the dry. You see, the lack of roll my car has is very beneficial when driving through a series of turns. However, with stiff sway bars I also notice that the car has an easier time braking traction because the car will not lean. In the rain, this is extremely obvious and this is why my car slides so easily.

I think its a toss up. AND, this toss-up can easily be noticed by comparing a BMW and Mercedes. BMW are designed to have a more sport handling setup. However, in poor weather conditions, I would <gag> favor a Mercedes because it has more roll and tends to be more stable under those conditions.

Thats just my view of things...

- Mike

[thx247]

In the setup cars I've driven the handling limit is obviously increased, but is much more knife edge compared to say a stock car.

How would having stiffer sway bars decrease the traction in the wet? Wet has the same properties as the dry, just less traction right?

Is it because the weight isnt't transferred enough to outside tires anymore?

I've heard of people removing sway bars all together in the rain.

[andrave]

thick sway bars in the rear would reduce your cornering ability, because they would over load the outside tires...
its about balance.

[Brian]

we all know 240sx can slide the rear end easily
adding a rear stabilizer bar increases this
adding rain makes things slippery
add em up.

[Var]

Originally posted by yeswepromise
we all know 240sx can slide the rear end easily
adding a rear stabilizer bar increases this
adding rain makes things slippery
add em up.

you'e be surprised at how hard it is to get my car sideways. open diff, falken azenis and 1.5 degrees camber in the rear. My car just wants to understeer all the time. I've messed around with tire pressure.. God damnit i wish i had never driven an ae86. That's how every car should feel.

[Flybert]

Here's a little story about grip in a slightly damp condition with 8/6 N1 PRO.

Of course with a stiff suspension on uneven roads in the wet can be a little dangerous but if the road is fairly smoothe, the car can hold pretty well. I also have to mention that I have AVS ES100 (195/55/15 on stock alloys) and a Tomei 2-way.

So I'm driving on the 605N to get on the 60W and there is that really fun onramp (decreasing radius right hand sweeper kind of in between 2nd and 3rd gear). It's not perfectly smoothe but makes for good times. As I'm approaching it this Civic (EF body type) comes flyin at about 90 from behind me (I was doing about 70 like always). I always go through this turn fast but I didn't want to make it seem like I was racing the guy. It's a 2 lane on ramp and he goes outside to inside like a person is supposed to but I didn't want him to go and do something stupid if I followed his same line so I just stayed in the inside lane doing my heel and toe routine. I sacrificed maximum grip by not taking the racing line but I wanted to see if my car could hang with him. Surprisingly, his car hung on really well in a slight wet condition compared to my fully raced out suspension setup. I felt I was approaching maximum grip on my tires and didn't want to get closer to the edge. I was really surprised how his car managed compared to mine. Then I'm not sure what happened but it looked like the guy induced off throttle oversteer and his car kind of spun out in front of me. It wasn't a full spinout. He just ended up facing the inside of the turn.

This guy didn't have coilovers. It seemed like he had some lowering springs but I couldn't tell anything else.

What I learned from this experience is that more roll and softer suspension in the wet helps out a great deal from what I could see with this guys car in this situation. He just pushed it a little too far. Thinking about it now, I wish I would have followed his same line to actually get a good comparison.

Another thing is that I'm still trying to get used to the way the 2-way makes the backend react. It kind of feels like 4-wheel steering at times.

[Var]

Originally posted by thx247
west, I know it sounds wack but consider again swapping those springs around. btw I appreciate the offer on smog test, I'll see what I can do with the car today.

I still have a 98 KA I could throw in.

Ground control recommended running at least 375 in the front(6.7k) They said it's for suspension travel reasons. But then my car's not slammed all the way so i may be able to do it.. If the case is the springs are too stiff then why do ppl set up stiffer in the front all the time? my biggest concern isnt at the limit handling. I am semi-content with that part of it. It's just the turn-in that i cant stand. No other car with 3 degrees camber in the front would understeer like this.

Dousan you know it all. since you know so much then tell me how to set up an s13 to always have more traction in the front than the rear without decreasing rear traction. swapping the springs is too much work. Should i adjust the front/rear ride height different?

And here's another question to anyone riding on KYB AGX.

WHY THE FUCK? did KYB make the shocks so stiff? It doesnt help for shit it just makes the car understeer more when you go to setting #4 in the front. Setting #2 is as stiff as it's gonna get without sacrificing grip...even on a smooth racetrack. The only thing i can think of is when the shocks start to wear out you can switch to a higher setting to compensate? i dont know or maybe they just blow instead of wearing out gradually. Im gonna try Koni's next time. Maybe the quality of the KYB isnt up to my expectations and i dont even know it cause they're the only shocks i've ever owned.

[S14DB]

I got the ST set and installed the rear then it started to rain so I drove home with the rear only. For the rest of the week the rear would come around hella fast. It rained again and I skided in a corner Quickly put in the BIG ASS front bar and no the can handles like a go kart.

I would recomend the ST set but put them both in all at once.

[old_s13]

flybert> What I learned from this experience is that more roll and softer suspension in the wet helps out a great deal from what I could see with this guys car in this situation. He just pushed it a little too far. Thinking about it now, I wish I would have followed his same line to actually get a good comparison.

No no no.. the difference THERE is the difference between something who drives a FWD car and someone who drives a RWD car. The reason his car recovered is because I think RWD is much easier to feel when the car is going to lose it. Plus, all the driver has to do is romp on the gas and steer MORE and the car will recover. Its the exact opposite of what RWD owners have to do.. and recovering a RWD car requires different technique which IMO, most people dont know how to do.


pimp> since you know so much then tell me how to set up an s13 to always have more traction in the front than the rear without decreasing rear traction. swapping the springs is too much work. Should i adjust the front/rear ride height different?

I think the resolution to this problem has to do with spring rate and shock stiffness. You need to play around with that and find a setting that will give your car the effect YOU want. You should look in to mimicing the setting that Kei Tsuchiya uses on the S13 they run on the "Drift King" DVD. With the diff suspension, that car had NO issues of understeer.

-m

[Brian]

*off topic sorry*

flybert - the better turn is when you take the 60 east onto the 605 south. 2 lane left hander. very fun.

*okay back on topic* :)

[s14slide]

O.K. I'm gonna give it a shot at trying to lend a hand here.

When your thinking about suspension, always remember that you can only use 100% grip at all times divided between all the tires. We'll keep it simple here and only use a F/R weighting. And you can figure how much grip you have by knowing where the weight of your car is. So when at a steady speed, your tires are using 50% in front and 50% in back. Now, when you brake at the limit you may be at 80% front and 20% back.
Now when cornering, you "want" a 50/50 balance between front and rear, which will give you a neutral balance feeling from a car. Now thinking in these terms, if you add a stiffer rear sway to your car, you have to factor in what other suspension peices you have on the car and how this bar will affect the overall balance of a car. Getting more oversteer in this situation may be better accomplished through softer front springs, or stiffer rear springs etc., etc..
Just remember, when you replace a soft squishy part for a stiffer aftermarket part, chances are you'll be transfering more weight to that part of the car, and replacing soft squishy bushings for stiffer ones really just tighten up response. I don't think any one here is smart enough to tune w/ bushings just yet.

Hope this helps.

[Flybert]

Originally posted by yeswepromise

flybert - the better turn is when you take the 60 east onto the 605 south. 2 lane left hander. very fun.


It's a two lane right hander man and I agree that that one is fun as well but not as fun as the other one.

*back on topic*

S14slide - There are a few people on here who have tuned their car using subframe collars. You can set them up for drift or grip depending on there placement.

[The ROMAN]

According to that chart

ADJUSTMENT .........................TO INCREASE UNDERSTEER.......................................T O INCREASE OVERSTEER

Weight Distribution ................. Move weight forward ............................................. Move weight rearward

I thought by moving the weight forward by taking weight OFF the rearend, like taking the spare tire and back seat out, a RWD car would slide easier because there's less weight pushing the rear tires down thus less rear wheel grip.

[s14slide]

Originally posted by Flybert


S14slide - There are a few people on here who have tuned their car using subframe collars. You can set them up for drift or grip depending on there placement.

I don't know exactly what you mean by this, but I was just giving an example w/ the springs. I use subframe collars on my otherwise stock (besides GR-2 shocks and t/c bushes) suspension and it seems to make it A LOT easier. I tuned grip cars and motorcycles way back when, before I got into drift. I was more or less "trying" to explain some suspension theory to help this guy better understand his car.

[s14slide]

Originally posted by The ROMAN
According to that chart

ADJUSTMENT .........................TO INCREASE UNDERSTEER.......................................T O INCREASE OVERSTEER

Weight Distribution ................. Move weight forward ............................................. Move weight rearward

I thought by moving the weight forward by taking weight OFF the rearend, like taking the spare tire and back seat out, a RWD car would slide easier because there's less weight pushing the rear tires down thus less rear wheel grip.

Now your getting into the territory of polar moment. Physics, fun stuff. Having that weight way out there from the center of gravity makes it more difficult to initiate but makes the rear end want to keep going, thus making the rear end of the car take longer to step out and more difficult to control because of the moment of inertia of the extra weight. Think of a weight on a string, the longer the string the more difficult it is to get moving and it also takes longer to stop and control it's direction, and if you use a shorter string w/ the same weight, it takes a lot less to do the same. Hang a weight from a string and you'll see exactly what I'm talking about. In short, the more weight you have (the weight multiplies the further it is from the COG when in a car trying to turn due to inertia), the harder it is to get the weight moving in a particular direction making itharder to control. Now in your quote, your thinking more of a drag racers ideal setup, where you want weight over the rear tires on the launch when the tires are more challenged for grip from a standstill. Don't get me wrong now, your right in what you say, but it by removing any weight from the car, you increase total grip by decreasing the load the tires have to carry. Now this is all in saying that I'm understanding what your trying to say. I drift w/ two spare tires where the back seat is and barely notice the difference from when they're out. I hope I explained all this right, but all in all in weight issues, you have to think about what your going to be doing w/ the car.

[tchenku]

you guys make it too complicated...

just go play gran turismo and play with the suspension settings :D

(the physics in drag mode are off though, in GT2)

[s14slide]

I could write another page on inertia and slip angles to finish this off!!



SLAP!!!!!(myself)
(talking to myself)JUST STOP, YOU NEVER KNOW WHEN TO QUIT!!!!:bash: YOUR GONNA LOSE AN EYE ONE DAY TYPING ALL THAT CRAP!!!!:hammer:

[The ROMAN]

Yeh I'm trying to build a drift car. I had some free time, so I striped the back of it (back seat, panels, spare tire, sound deadening) and now it feels like I can drift smoother without dealing with the dead wheel (open diff), but maybe that's just cause my tires have ZERO tread now.

[Var]

it must be your tires. i did the same to my car except im running azenis and still too much grip in the rear. also got like 1.5 negative rear camber. what tires are you using in the rear?

[The ROMAN]

Bald Nissan LE Steeles I got off my friends 240. I put my alloy wheels back on though cause the steeles are about to blow out from all my "pratice" :D