Hmm, I think its also important to note that the reduction in body roll frees up additional suspension travel that would otherwise be taken up. It also gives a crisper turn-in.shorthand said:
What are your thoughts about that?
Swaybar Physics
OK, what is a swaybar and what does it do?
When you ask most tweakers this question, the answer you get is "It reduces body roll." When you follow on and ask, why is this good, the answer you get is "It reduces weight transfer by keeping the body level."
While the first answer is completely correct, the second answer is totally wrong.
Let's talk about weight transfer. Only one factor determines the % weight transfer in a curve. That is the angle from the center of gravity to the outside wheel. Therefore, there are only three ways to reduce lateral weight transfer.
1) Move the center of gravity further away from the outside wheel. -- This works great on oval tracks. Kind of useless for the street as you get closer to the other wheel when you do this.
2) Lower the center of gravity - usually by dropping the ride height, but racers do all kinds of things to lower their CG.
3) Widen the track - fender flares (think 1985 BMW M3), etc.
I'll avoid a lenghty discussion of how weight transfer effects tire grip. Let's just say for now that the more heavily loaded a tire is, the less effecient it is in carrying its appointed lateral (turning) load.
So, if body roll is not a factor in weight transfer, why do you worry about it? The answer is that it is a secondary issue, not nearly as important as weight transfer. Body roll can have three effects:
1) Annoy the driver
2) Lessen tire performance through camber changes
--NOTE: Double wishbone suspensions compensate for this effect very effectively and only experience issues at extreme body roll angles - this is why Honda is so commited to this suspension geometry across its line (as much as possible)
3) Make left-to-right transitions slower
I'm sure you are saying at this point:
Enough already - tell me about swaybars.
The reason swaybars are important is that they do have an important effect on weight transfer.
A swaybar is just a spring that couples one side of the suspension to the other with a given spring constant. (A coil spring is just a tortion spring wound into a helix, actually.) It carries the force of the weight transfer as opposed to having that force transmitted through the coil spring to the frame to the other three coils.
The reason the swaybar is important is that it transfers the weight to only one other coil, not the other three. Therefore, you can use swaybars to tune the amount of weight that is transferred to the front or rear axle because of the LATERAL weight transfer.
It is desirable for stock FWD cars to understeer, that is have the front wheels loose lateral grip before the back ones. The reason is that if a FWD car OVERSTEERS, the best way to get out of the skid is to floor the accelerator. As you can imagine, this could cause serious trouble for soccer moms. (Read lawsuit, or perhaps a book titled Unsafe at Any Speed.)
A favorite techinque to make sure that you get a car that understeers happily in emergency maneuvers is to have the weight transfer preferentially on the front axle. This means putting a big swaybar up front and little or no swaybar in the back. This puts lots of load on the front, outside tire, and it slips accordingly. This is also a major reason that front tires wear so much faster on FWD cars. (You can guess the other reason.)
Note: the weight transfer to the front happens because the stock-configured car will stick its butt waaaay up in the air when cornering hard while the nose will dive
Well, we aren't soccer moms (or if we are, we don't drive like our peers). We know that there is better handling to be had if we neither understeer or oversteer, but handle neutrally when under full throttle.
Therefore, the quickest, cheapest, easiest way to rememdy the situation is to match the front swaybar with a slightly smaller rear swaybar. This will even up the weight transfer so that near equal weight is on the two outside tires, as opposed to only one of them.
We still want a little understeer on the street, as snap oversteer is BAD, not to mention scary. I thank God that it has only happened to me on an autocross course.
Note: Snap oversteer is where the car oversteers suddenly and without much warning. It is very hard to recover from without VERY quick wrists, espically on a FWD car.
That's the story of swaybars - the real empasis on a double-wishbone equipped car is really to balance the weight transfer between the front and rear axles. The advantage of using a swaybar without changing springs is that you retain your stock ride quality.
I love my swaybar. It have me 5mph in corners on the stock doughnuts. On a Cvic, keeping the revs up in those corners is worth many, many horsepower. The result is even better on the Si Rims. I was a little surprised at the sensation that the tail just tucks in now and doesn't rise. Now I'm just spoiled. Beyond upgrading my shocks for ride quality reasons (the Si rims threw off the suspension tuning, much to my surprise), I plan to make no additional suspension modifications. I am, believe it or not, happy.
Please feel free to post any additional questions.
When you ask most tweakers this question, the answer you get is "It reduces body roll." When you follow on and ask, why is this good, the answer you get is "It reduces weight transfer by keeping the body level."
While the first answer is completely correct, the second answer is totally wrong.
Let's talk about weight transfer. Only one factor determines the % weight transfer in a curve. That is the angle from the center of gravity to the outside wheel. Therefore, there are only three ways to reduce lateral weight transfer.
1) Move the center of gravity further away from the outside wheel. -- This works great on oval tracks. Kind of useless for the street as you get closer to the other wheel when you do this.
2) Lower the center of gravity - usually by dropping the ride height, but racers do all kinds of things to lower their CG.
3) Widen the track - fender flares (think 1985 BMW M3), etc.
I'll avoid a lenghty discussion of how weight transfer effects tire grip. Let's just say for now that the more heavily loaded a tire is, the less effecient it is in carrying its appointed lateral (turning) load.
So, if body roll is not a factor in weight transfer, why do you worry about it? The answer is that it is a secondary issue, not nearly as important as weight transfer. Body roll can have three effects:
1) Annoy the driver
2) Lessen tire performance through camber changes
--NOTE: Double wishbone suspensions compensate for this effect very effectively and only experience issues at extreme body roll angles - this is why Honda is so commited to this suspension geometry across its line (as much as possible)
3) Make left-to-right transitions slower
I'm sure you are saying at this point:
Enough already - tell me about swaybars.
The reason swaybars are important is that they do have an important effect on weight transfer.
A swaybar is just a spring that couples one side of the suspension to the other with a given spring constant. (A coil spring is just a tortion spring wound into a helix, actually.) It carries the force of the weight transfer as opposed to having that force transmitted through the coil spring to the frame to the other three coils.
The reason the swaybar is important is that it transfers the weight to only one other coil, not the other three. Therefore, you can use swaybars to tune the amount of weight that is transferred to the front or rear axle because of the LATERAL weight transfer.
It is desirable for stock FWD cars to understeer, that is have the front wheels loose lateral grip before the back ones. The reason is that if a FWD car OVERSTEERS, the best way to get out of the skid is to floor the accelerator. As you can imagine, this could cause serious trouble for soccer moms. (Read lawsuit, or perhaps a book titled Unsafe at Any Speed.)
A favorite techinque to make sure that you get a car that understeers happily in emergency maneuvers is to have the weight transfer preferentially on the front axle. This means putting a big swaybar up front and little or no swaybar in the back. This puts lots of load on the front, outside tire, and it slips accordingly. This is also a major reason that front tires wear so much faster on FWD cars. (You can guess the other reason.)
Note: the weight transfer to the front happens because the stock-configured car will stick its butt waaaay up in the air when cornering hard while the nose will dive
Well, we aren't soccer moms (or if we are, we don't drive like our peers). We know that there is better handling to be had if we neither understeer or oversteer, but handle neutrally when under full throttle.
Therefore, the quickest, cheapest, easiest way to rememdy the situation is to match the front swaybar with a slightly smaller rear swaybar. This will even up the weight transfer so that near equal weight is on the two outside tires, as opposed to only one of them.
We still want a little understeer on the street, as snap oversteer is BAD, not to mention scary. I thank God that it has only happened to me on an autocross course.
Note: Snap oversteer is where the car oversteers suddenly and without much warning. It is very hard to recover from without VERY quick wrists, espically on a FWD car.
That's the story of swaybars - the real empasis on a double-wishbone equipped car is really to balance the weight transfer between the front and rear axles. The advantage of using a swaybar without changing springs is that you retain your stock ride quality.
I love my swaybar. It have me 5mph in corners on the stock doughnuts. On a Cvic, keeping the revs up in those corners is worth many, many horsepower. The result is even better on the Si Rims. I was a little surprised at the sensation that the tail just tucks in now and doesn't rise. Now I'm just spoiled. Beyond upgrading my shocks for ride quality reasons (the Si rims threw off the suspension tuning, much to my surprise), I plan to make no additional suspension modifications. I am, believe it or not, happy.
Please feel free to post any additional questions.
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After talking with a few guys, im fairly certain that the new rates will be 250 lbs front and 200 in the rear. I know that doesnt sound like much to you honda folkPseudoRealityX said:
, but its on the edge of streetability in my car.that will make a huge difference. my roommates golf III had h&r sport springs which are virtually the same as the st sport springs and switched to shine racing springs (225#fr 120#rr) night and day difference with the turn-in and reduction in body roll. mac strut suspensions due have one flaw, and that is that they love to pull up the inside front tire. shine racing does the vw's with no front bar and a large rear bar. i'll let you guys know how the golf performs, i'm betting its going to be hella fast.
honda doesn't actually get all that spring rate to the tires. wheel rate on my car is about what you're planning on going to. i'm guesstimating because i can't find any literature anywhere that tells me the spring rates that i have right now. maybe next season will find some nice koni double adjustable coil-overs on my car.
honda doesn't actually get all that spring rate to the tires. wheel rate on my car is about what you're planning on going to. i'm guesstimating because i can't find any literature anywhere that tells me the spring rates that i have right now. maybe next season will find some nice koni double adjustable coil-overs on my car.
Yup, i have a buddy building a first gen Scirocco for SM. His suspension setup sounds assbackwards, but its seen success with other drivers, so hes going to use it.solo-x said:that will make a huge difference. my roommates golf III had h&r sport springs which are virtually the same as the st sport springs and switched to shine racing springs (225#fr 120#rr) night and day difference with the turn-in and reduction in body roll. mac strut suspensions due have one flaw, and that is that they love to pull up the inside front tire. shine racing does the vw's with no front bar and a large rear bar. i'll let you guys know how the golf performs, i'm betting its going to be hella fast.
honda doesn't actually get all that spring rate to the tires. wheel rate on my car is about what you're planning on going to. i'm guesstimating because i can't find any literature anywhere that tells me the spring rates that i have right now. maybe next season will find some nice koni double adjustable coil-overs on my car.
And yeah, i understand wheel rates, but since the VAST majority of hondas use the Double wishbone, i threw that in there so someone didnt try to tell me to use like 500# rear springs.
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