What anti roll bars to use with 200/800 Lb springs

[K4fxd]

Title says it all. The car is pretty balanced with the factory base bars but they do allow a lot of roll. I want to keep the balance and reduce the roll. I like a balanced car at the edge.

Been debating the 1.5 inch or the 1 3/8 from Steeda.

I think the bigger bar will be best with the soft springs, but I don't know which rear bar to mate with it. A kit is offered with the small bar.

Pretty much everything on the car is blue or hammertone, I don't want to do red. I don't like the blue either but it is not so in your face.

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[NightmareMoon]

you don’t need the 1.5” bar, chances are you won’t be running the 1 3/8 on it’s stiffest setting either. The bigger bar is only really needed for track/autox with front springs 2x-3x as stiff as yours. Steeda will recommend you start on the softest setting on both front and rear bars, which is still pretty stiff. IMHO even the medium setting is a lot. The suspension needs to move to work.

 

[K4fxd]

This car is for daily fun. I thought I had it handling good and I was done modding it. Then today I tossed into some tight turns and ....

Since the smaller bar is probably enough is there a reason, besides color, to go with steeda over any other brand of same size adjustable bar?

 

[Norm Peterson]

This car is for daily fun. I thought I had it handling good and I was done modding it. Then today I tossed into some tight turns and ....

... and what, exactly?

Can you describe what you were doing to "toss [it] into some tight turns" in a little more detail? Any chance that what you were seeing was a combination of roll plus pitch more or less "ganging up on" the outside front tire and suspension? How much harder did this cornering get, relative to what your average cornering the rest of the time to date has mostly been?


On edit, less roll with the same balance is probably going to mean you're going to want both bars to be adjustable. Start with both full soft and first work on the front bar setting to get roll down somewhere close. Finish tuning the balance with the rear bar adjustment. I would think that 1-3/8" (35mm) would be enough front bar, 1.5" would be 40% or so stiffer but wouldn't reduce roll by that much, and once you're down in the 2°/g neighborhood on street tires you're well into the realm of diminishing returns anyway.


Norm

 

[K4fxd]

Thanks Norm.

Yes that was a bit vague but it leaned more than I liked. This was the first time I got to go high G turn at 100 +. When it transitioned tighter the car felt like it was rolling over on both the front and rear tire. Might be a camber issue?

It is definitely rolling more than 2*

I looked at the car this morning and the driver side sway link is bent. It wasn't bent when I upgraded the brakes a week ago.

I figured I'd need both Front and rear.

 

[Norm Peterson]

Running into +camber could be part of it.

For sure the bent endlink would have thrown more roll in right turns at you than you'd have expected, at least for the time(s?) that the bending actually happened. This is somewhat related to what I was fishing for in asking how your 'intensity' for this cornering compared to that for your normal cornering, since perceptions tend to be based on what's "normal". IOW, for a person whose normal cornering doesn't reach much past 0.3g, an 0.9g turn is going to feel to that driver like there's more roll happening than a 1g corner feels like to the driver who commonly gets above 0.5g, maybe once in a while up to 0.7g

There's about half a degree of roll per g coming from tire vertical stiffness not being "infinite". Maybe a bit more depending on tire size and inflation pressures. Not much you can do about this that makes much difference.

I'd be surprised if the S550 rolled much more than about 2.5°/g in the suspension.


Norm

 

[K4fxd]

Sounds like you are saying I don't need bigger bars?

If they won't help I don't want to waste my money.

I do like G forces so tend to push the limits whenever safe.

 

[Norm Peterson]

I think the first thing you need to do is get better endlinks. That'll at least eliminate whatever contribution might have been coming from flexibility as it/they buckled slightly out of 'straight'. Then give everything a little more time, given that you seem to like where the handling balance sits right now. And watch the outer shoulders.

The thing is, as long as the car takes a set quickly enough (and your steering inputs are smooth enough) there isn't much need to reduce roll any further. Dampers come into play here as well.


Norm

 

[K4fxd]

Better end links, yep ordered today.

It takes a set a ton better than it did before I started down this rabbit hole but still has some bushing deflection in the rear, but livable.

I started out racing go carts and that is the feel I'm looking for in a corner. I know a suspended street car will never feel that tight, but I want to get as close as is practical.

 

[NightmareMoon]

100mph decreasing radius corner? Is that what I read?

swaybars help withtransitions (switchbacks) and they can influence the natural bias to understeer or oversteer at the limit, but they won’t usually add grip. Grip is the tires job.

i do recommend a set. Personally I guess the BMR (comes in hammertone grey) may fit a little better than the Steeda design, but they both should work.

bending the endlinks is common. a lot of us have done that, I’m not sure what if any impact the slight bend we get has on handling.

 

[S550_Newbie]

Anyone use a Steed Extreme G-Trac K-Member before? Did it help the front feel tighter? I was looking at some modest ways to stiffen up the front a bit more myself on a PP1 car.

 

[K4fxd]

I've got the BMR 4 point. I don't like the loss of ground clearance with the steeda part.

It seems to help when braking hard.

I won't take it off.

 

[S550_Newbie]

I've got the BMR 4 point. I don't like the loss of ground clearance with the steeda part.

It seems to help when braking hard.

I won't take it off.

I don't see where you lose ground clearance.

 

[K4fxd]

Where the steeda brace mounts in the front it loses about 1 inch of ground clearance.

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