Wondering what the Indications of too much sway bar would be. Is it lifting a tire in a corner? For the record we are not talking about oversteer or understeer. As there can be multiple factors that affect that, such as camber, tire pressure, caster, etc. I am literally talking about the size of the bar being too big for the effort the suspension goes through.
Within reason, there isn't "too large" a bar, unless the one on the other end of the car isn't compatible. Some people like all the springs, some people like all the bars, and nobody is really wrong.
In reply to Streetwiseguy :
That is good to know. I think I am more of a swaybar guy myself. I kind of like the plush ride, along with having travel.
NASCAR went to ridiculously huge bars, like 4", and soft springs so the aero sucks the cars down to the bump stops.
Apparently their handling is precarious, but it's faster, so the drivers dealt with it.
In generally the car will start to pick up the inside wheel, the car will also have a skatey feel to it as well. It won't build mechanical grip the way a softer set up will. Unless a car has a good bit of aero I try to run them as soft as possible, it won't have that instant feel but it will be faster.
My biggest concern is slaloms. We have at least one at every autocross. I've read sways help with directional changes.
As with all chassis changes fixing one thing to be faster in a slalom may make you slower everywhere else. My F500 / F-mod car has no sway bars whatsoever (they're not allowed in the class) and I solve the rapid transitions with oversteer.
What chassis? Another indicator might be too much inside wheelspin on that axle. You really need to evaluate the setup as a whole though.
Pete. (l33t FS) said:NASCAR went to ridiculously huge bars, like 4", and soft springs so the aero sucks the cars down to the bump stops.
Apparently their handling is precarious, but it's faster, so the drivers dealt with it.
2.625", and they're hollow; occasionally filled with tungsten ballast. But yeah, "precarious" is accurate. The chassis springs don't really do much for platform control, the "bump stops" are coil springs now, so it's really two different sets of springs. The chassis springs are just along for the ride once the car gets up to speed starts making some downforce.
In reply to unevolved :
My bad, maybe 4" was the diameter of the tube that the bar rides in.
Pete. (l33t FS) said:In reply to unevolved :
My bad, maybe 4" was the diameter of the tube that the bar rides in.
Yeah, roughly. Can't remember the exact diameter.
Most of the occasions that I've seen a car lift a wheel it's usually the opposite end that drives the car. Like a FWD car lifting the inside rear wheel or a 911 lifting an inside front wheel. While this is not an ideal set up it can work on a particular car when it "fixes" another problem that car may have getting around a corner.
With FWD cars it means that your reducing under steer and that's a good thing, of course what your doing is reducing the total rear grip the car has but if it makes the car faster then it's all good.
In reply to jimbbski :
Lifting a wheel also means that suspension changes have an inverse effect at the other end, because you are longer juggling the weight transfer distribution, just body roll. Once one end has 100% load transfer then you can't make use of that tool anymore. Golfs would reduce understeer by stiffening the front suspension because the tires would lose less camber.
I did the plated rear beam thing in my '89 and under mild cornering it made a difference, but at max cornering all it did was make the inside rear tire 6" off the ground instead of 3". I was too broke to stiffen the front, so I put lowering springs in the rear to reduce how much the car wanted to roll in the first place. HUGE difference. I cut the plate out and it was even better.
Carrying a front wheel in a rear driver usually just means you have excellent acceleration grip.
Here's the opposite of too much bar. But the question is how much is there to gain by adding more bar and flattening this puppy out in the corners? And will reducing the roll help corner exit grip or make it worse?
Gratuitous example:
bigben said:Here's the opposite of too much bar. But the question is how much is there to gain by adding more bar and flattening this puppy out in the corners? And will reducing the roll help corner exit grip or make it worse?
You can't really judge just by body roll. What you're really attempting to control is your camber - and honestly looking at your RF tire that pic doesn't look too bad.
The other factor is when you corner what does the car do - is it loose at corner entry, or does it understeer? What about mid-corner and corner-exit?
Being an RWD platform the typical plan would be a larger front swaybar and/or increased front spring rates to control the body roll(and thus camber gain), then use the advantage of RWD to help the car rotate.
The sway bars on my Datsun are straight out of the Nisssan Competition prep manual. In the first pic ignore the fact that it is carrying the inside front, that's do my pounding over the kerb, the important thing to look at is the outside rear tire deflection, note how much I'm getting out of the car. The second pic shows how relatively flat the car corners. Think Goldie Locks, you want neither to hard or to soft. to soft = camber change, to hard = skatey/less grip.
I'm going to throw this in here. Don't fall for the FWD cars just need a RSB to corner well E36 M3.
I added an 034 Motorsports 25.4mm solid RSB to my 2011 GTI. The sway bar is +200% or +290% stiffer than stock. It made the car corner better but mainly by allowing the rear tires to slide more. It also made the car feel funny. The back would set before the front end and it kind if felt disconnected until the front end set into a corner. Then I read this article:
It made a lot of sense to me so I ordered an H&R 26mm FSB and installed it. Wow! Now the car just points and goes. The tires are heating up evenly after 20 minute sessions at Laguna Seca. I'm also not having to run a ton of camber (-1.4 degrees all around) I wound up with the RSB on the softer setting (3x stock) and the FSB on the harder setting (2.25x stock). The car is really well balanced now. I'd actually like to try a 24mm solid RSB and see if I can get both bars on the softer settings for DD duty.
Just to be a contrarian, I will point out my fastest laps in my CRX were with either no sways, or just a lighter rear sway. No front sway bar at all. I have 3 thicknesses of bar for front and rear, but usually use the lightest. But here is the kicker tht makes this relevant: Tires.
Tires determine if I go small/no bar, or bigger bars. The stickier the tire, the more grip I have to play with and the less body roll I want. Sporty street tires is what I usually run, so right now only a rear bar.
Second major consideration is springs. Harder bars tend to like softer springs and vice versa, otherwise you end up with way too high a wheel rate. But this is hotly debated. Some swear by the "any suspension works if you dont let it" philosophy. I personally want to see the suspension travel as much as possible to keep the rubber on the pavement.
Third: rest of suspension! Struts like more bar than wishbones, due to camber/tire deformation ime. Every suspension has quirks to work around. In my civic its mostly rear-steer and lack of weight making my balance poor in typical fwd fashion. I found more caster in front and a bit of camber in rear helps a bit, as well as letting the car lean a bit more with softer (still harder than stock) springs.
Bonus confusion: I should throw in that big springs/bars will raise your wheel rate and be harder on shocks. OEM style tend not to like lowering, bigger springs, and harder driving without seals blowing more frequently. Make sure your shocks are in good nick before goin nuts. Also be aware heavier cars are less sensitive to small changes compared to my 1760lb honda.
You add more bar to get LESS grip on that end in general as I understand it.
In reply to Nugi :
All of this is correct. I was just asking because I installed a set of roadster sport sway bars on my NC. I am running the stock screens and stock shocks. Currently on the softest settings at both ends, the car feels fantastic. As you said, the rubber actually sticks to the road and prevents the car from feeling like a barge when slaloming
Nugi said:You add more bar to get LESS grip on that end in general as I understand it.
True, but the "in general" part of that statement assumes a decently close to ideal setup that you're looking to fine tune. As with most suspension stuff, it's a bell curve of sorts. If you're way at one extreme or the other, the effect can be inverted. In this case, if you have so much body roll that the outside tire is losing camber and contact patch substantially, then adding more bar to reduce body roll will increase overall grip (possibly at the expense of a bit of initial turn in grip). Then once you get in the window of a reasonable amount of roll stiffness, your general statement becomes true. Your situation with your CRX is still working on the same concept, you just accomplished the extra roll stiffness through stiffer springs instead of a stiffer bar. There's a lot of arguments that that's actually the better way of doing it, but also a lot of reasons why it's not always feasible.
In reply to dps214 :
Most definately. Hence my weasel-wording with 'generally'.
My car is a pile of compromises, but most are. I built mine on the cheap with 'mechanical feel', handling on rough and narrow mountain roads, and extreme budget (still under 3k all in!) as my primary goals. The rough roads here seem to reward suspension independence over roll-resistance, hence the slight spring-bias. I am still a bit under the commonly suggested settings for my platform, spring rate-wise. If I still lived down south, with its prevelance of straight roads and 90deg corners, and flat tracks, I might choose a bigger bar setup. In any case its cheaper and easier than doing the springs.
But since I didnt answer the main question, Ill say excessive wheel lift is usually an indicator. When I was a teen, we would show off our rock hard suspension by driving up on a curb and lifting one (or 2!) wheels in the process. I'd say thats too much, even for many racecourses, unless you want that very very literal 'go-kart feel'.
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