froggy47

I have adjustable links so can take out the preload any way they are set.

So is it true/possible that I actually have 5 settings, not just 3?

Softest = outer & outer
Firmer = 1 outer & 1 middle
Firmer = both middle
Firmer = 1 middle & 1 inner
Firmest = Both inner

Yes/no?

Or will this way have some unintended consequence I haven't thought of?

ErnieN85

short answer yes 5 settings.
unintended consequences........ none i can think of

froggy47

Thanks Ernie!

383

Wouldn't #2 and #4 cause one side to be stiffer than the other? the lever arm comes from the center sway mount/bushing on the chassis to each side so making one shorter would stiffen that side only. right?

63Corvette

Depends on your definintion of "stiffer".
Disconnecting only one link completely, makes the bar "infinitely softer".

Solofast

The short answer is yes, for a given roll angle you will have more or less force on one side or the other. That will mean that the car will push more in one direction and be more loose in the other. The short arm will have more force on the wheel on that side than the wheel on the other side loses, so the amount of weight transferred isn't the same as with the settings being equal.

If you had a car with wedge in the spring setup or if you couldn't get the car balanced properly you might want to offset the arm length, but for a normally set up car it isn't something that you would want to do.

Xian

Errrr... No. Unless your bushings and bar are bound, this isn't the case. The level of roll resistance doesn't vary by side since the bar should rotate freely.

Christian, who's split bar adjustments like this for years on multiple different types of cars.

SouthernSon

Hummm.....the bar transfers the spring rate of the inside spring to the outside spring to add spring rate to the outside suspension spring in order to resist body roll. If the farthest hole on one side is combined to the closest hole of the other side, I would think you are only compromising the leverage afforded by the closest hole (stiffest) by lessening the input force...in other words, the bar incurs more twist and less leverage. I see no reason for it.

froggy47

Yeah, that's what I was thinking & my bar is free as can be. To be simple, it's just longer or shorter, that's all, that's it. But here's a "twist" as you shorten the bar, do you have to lengthen or shorten the link? If it's lengthen then you are negating the shorter hole, yeah? I'm at a computer & not under the car so I can't really measure it or count the turns.

383

So youre saying that if (theoretically) one side was 2" from the bushing and the other was 2' from the bushing the roll resistance would be the same in both directions?

redtopz

You guys are over thinking this. The end links are fixed to the lower control arm and will center the bar between them because the bar slides in the bushings. The most you would ever be off is one hole because if you were off 2 holes you could just make each side equal. I have been fine tuning my rear bar one hole at a time for years and it work fine.

Xian

I'm not running an adjustable rear bar on my C5Z so I can't directly speak to whether the endlink lengths would actually* need adjustment. Ideally you'll want to adjust the endlink length with the car sitting on the ground and at the normal ride height. This will eliminate any swaybar preload (preload is what can make it handle differently in right vs. left, not split adjustments like we were talking about).

For the folks who think setting a bar stiffen one side and soft on the other will result in a higher swaybar rate for one direction than the other, imagine the bar coming completely off the car. Put it on your work bench, mount the center of the bar, and bolt one end to the bench. Start hanging weights off the free end of the bar in order to measure rate. The rate you get will be a function of the length of *both* lever arms. Now swap sides of the bar with the (previously) free side bolted down and hang weights on the side that was previously bolted down. You'll get the same rate for the bar vs disparate weights for right and left sides (unless the bar is bound up in its brackets, at which point you have a torsion bar and not a sway bar).

*A change from one hole to the next will result in a longer (or shorter) distance that the endlink has to bridge. Depending on the courseness of the holes within the range of adjustment, the endlink location relative to the swaybar holes, and the length of the endlink you'll end up with varying degrees of how much adjustment is actually needed. Imagine the extremes of adjustment; you've got a short endlink that was attached to the bar directly above where the link attaches to the lower a-arm. Now imagine moving that to a hole 6" further out the swaybar arm. It won't reach, right? Now imagine a scenario where the hole that it's attached to is at a 10* angle to the rear of the a-arm and you're moving it to a hole that's 10* off the front side of the a-arm. This adjustment would make little to no difference in endlink length.

rfn026

The real trick is having enough driving ability to know what to do. You adjust the bar based on what the car is doing in the middle of the corner.

All Corvettes understeer on entry.

All Corvettes oversteer on exit.

It's all about the middle of the turn.

Richard Newton
Sway Bars

ErnieN85

that is the hhard part.

Solofast

All you have to do is a summation of the forces and moments on the bar to see that the forces on each side are most certainly different.

For instance, if the bar has a fixed amount of twist in it, and the arm on one side is twice as long as the arm on the other, the amount of force on the short arm side must be twice as high as the force on the other for the moments (which controls the amount of twist and which have to be equal if the bar isn't bound up) to be the same.

And as someone noted above if you put a really long arm on once side and a really short one on the other the short arm side would load and unload the wheel on that side while the other would have almost no effect.

What this would do is make the bar more effective (higher roll stiffness) on the side with the short arm. If for instance the short arm is on the drivers side the car would have more oversteer turning right than it does turning left. Conversely, that setup would result in more push in left hand turns. I can see how this could be an advantage, but it's really more like adding wedge into the chassis since it changes the roll vs force transfer from one side to the other.

I don't doubt that you don't notice that it's different since in practice, the lengths aren't very different, but there is no way that the forces on the end links are the same if the arm lengths are different. Come on guys, this is just simple math.

froggy47

Good point and leads me to my real world question.

Right now my rear bar is full soft (both outer holes) Front bar is not adjustable. Doesn't matter what the bars are. Car is pretty darn neutral for how I drive it. 335 a7's putting the power down good. Probe tire temps are ideal (alignment). So I want a touch more mid corner oversteer (loosen it up).

I think if I start to firm up (shorten) the rear that will do it.

Yes/no?

Xian

I agree that it's simple math and a simple concept... that you're missing.

The roll stiffness that the bar contributes is determined by the length of both arms. In the "one long, one short" arm scenario, the short arm side will deflect less *but* the long arm side will deflect more. If you turn the opposite way, the long arm deflects more than the short arm. The total roll resistance is the same in both directions and the car doesn't handle differently turning one way versus the other. Again, the the center section of the bar was solidly mounted, you'd be 100% accurate but that's not the case...

FWIW, but in my FWD stuff I was running rear bars that were in the 2000# per inch rate (one wheel bump, double that for roll). If your math was correct, I'd have ended up with dramatically different rates on the LR vs RR that would have been EASY to quantify via on track balance problems.

Xian

Keep in mind that I haven't played with bars much on these cars BUT I don't know that's what I'd do for the situation. My issue with adding rear bar is that it seems like you'd add a little entry and mid-corner looseness as well as reducing inside rear grip (which could hurt corner exit speed). I can't say unequivocally that it's the rigt answer but I'd want to try less rear toe-in first before I added rear bar.

Christian

froggy47

Thanks, hmmmm, got to think on that a bit, I kinda like my rear toe in, wear is good, I leave it same for street & autox, puts power down good.

I would not mind a "little" corner in & mid corner loose.

Maybe just have to try it.

Xian

Yeah, I'd be cool with the entry/mid corner behavior... it's the corner exit thing that would give me pause. Maybe try the bar (because it's easy) but be ready to reduce rake or toe in if corner exit begins to suffer?