Handling effects of a heavier front sway bar

[walterk55]

I will soon put on a heavier front sway bar on my 1996 C280. The new bar is from a C280 Sport and has more torsional rigidity.
What do you think I can expect in terms of changes in the car's handling? thanks
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[SLAMMED_C]

How much thicker is the sport bar compared to your stock ones?
I honestly don't think much of a change with a sport bar. You would need to go with a substantial upgrade to notice anything, like an Eibach upgrade.
The wheels will feel more planted in the corners.

[Vetruck]

How is the balance of the car right now? The bigger bar will make the balance go towards "push" and the car will not want to turn as easy as it does now. Going larger in rear makes the car go towards "loose". All a swayvar does is controls upper body roll (or otherwise known as "positive roll rate" As larger bar resists this, but it will also cause less independant moverment of the front suspension and thus loose mechanical grip over uneven roads. It will however if used in a blance set(meaning both front and rear) will help aid in lateral footprints keeping them flat over smooth surfaces, but then again can hurt over bumpy surfaces in lateral grip also.

In other words, every car is different based on tire choice, shock settings, engine weight (Ie- V6 ,I4, or I6) whicj can vary the chassis front to rear weight bias- Swaybars are merely used as a FINE TUNING instriment to even out balance of front and rear grip- only you will be able to answer this by driving your car, no one else can.

To five you an example of what I am trying- I have a lightweight nose 4 cylinder car and am leaving the stock swaybar. I am going slightly heavier rate springs to help further support the chassis roll AND brake dive while leaving the independant wheel movement more free with the smaller OEM swaybar. This alone will make the nose of the car push- so out back I am leacing the OEM springs BUT I anticipate just going to a larger aftermarket swaybar only in the rear to control the heavy upper rear roll weight of the 4door chassis yet not to help unload the rear chassis with a heavier spring back here- rather by using the OEM lighter rate springs that will not unload as uch thus throwing less bosdy weight forward on heavy braking. In corner balance I need to up the rear swaybar then to incease the lateral load so as to help lift presure off the inside rear tire on corner entracne so the car does loosen and turn. The rear bar.

Most importantly in doing all of this, I am using Koni adjustable shocks so I can use the rebound settings to fine tune the dynamic loading and unloading of the chassis. If its still tight going into the corner? I increase rear rebound rates. If its tight coming off the corner increase the front rebound settings

[Mike51809]

With all these suspension questions and explanations we need a thread on tires to utilize it :)

[Vetruck]

With all these suspension questions and explanations we need a thread on tires to utilize it :)

TIres are a big thing people overlook in vehicle handling. It is one of the major factors as to why people will have varying opinions on ride quality with a certain shock and spring combo.

Lets take for instance a Bilstein B8 and a Eibach combo. take idential cars that use them- one guys says its great, the other says its on the firm side and a bit harsh. The first guy might be using 17" wheels with lets say a good sidewall quality tire like a Goodyear Assymetrical 40 series, where as the other guy might be running 19's with a 30 series tire that is also crappy structure like a budget Hankook all season with a soft sidewall bobble that distrots fequencies when the spring overpowers the small but weak sidewall.

Whether using a low series sidewall tire, or a large series sidewall tire (based on what wheel diamter you use) you will always get a better ride quality focusing on reveiws of professional tire tests showing ride comfort. Not all tirs of the same size ride the same- not in the least bit. You simply change brand of tires from lets say a 225/40-18 Goodyear, to a 225/40-18 (same size, just different brand) lets say Fusion tire, the ride quality will differ. Which is better? pprobably the more expensive tire because more technology when itno it to weave the sidewall structure fore comfort and handling. Expensive tires cost more for a reason, it takes more complexity to make them out of better quality materials and weaving than it does a budget tire. Its like using a bullet proof vest comparing wearing a tank top to stop a bullet (extreme example, but you get the point on material quality for structure.) That makeup of tire material and structure weave make for varying ride qualities even if the tire look the same on the outside in size.

Varying sizes make for diffrent ride quality also.

So what works? you unfortunately have to try it. I have had cars dialed in ride qualty AND handling to later have a brand and size of tire discontinued. I then had to go to a new size and new brand and consequently had to retaylor the suspension to fit the new tires being used.

Case in point on this, My Chevy truck I run 19x11 rear wheels. I used to run a Yokohama Advan 295/50-19. It is discontinue, and to find a set of tires that match in brand and style that I can run on both my font 18x9.5's as well as my rear 19x11's I had to go to a Pirelli Prosso's in a 285/45-19 rear rather than the 295/50-19 I initially tuned the suspension to.

[John Jones Jr.]

Most importantly in doing all of this, I am using Koni adjustable shocks so I can use the rebound settings to fine tune the dynamic loading and unloading of the chassis. If its still tight going into the corner? I increase rear rebound rates. If its tight coming off the corner increase the front rebound settings

Vetruck, what's 'tight' into a corner, understeer?

[Vetruck]

yes.

The funniest way I have hear it presented is Tight is whent he front end of the car hits the wall, loose is where the rear end of the car hits the wall.

Often by reducing rebound rate will work, but mainly a shock compression decrease is in order and is the best cure. If you do not have compression adjustment then simply reducing the hold down force of the reound will allow for a little quicker return of the suspension to absorb the next bump instead of the tire sidewall having to. Reducing rebound will increase body roll into a corner though. You have to play with things to see what is best for you

[walterk55]

Thanks for the great replies. Since we got into tires and shocks, here is the full picture. The C280 is running on stock 15" wheels with 205 55 Cooper CS4 tires. The shocks are KYB Gas-a-Just schocks. Tires and shocks have little wear. Springs are original. I think the suspension is somewhat "soft". I like the KYB shocks. I love the Cooper CS4 tires - they hold nicely and are comfortable.

[walterk55]

The sport sway bar is in and this weekend I did a 400 mile round trip - the car is slightly flatter in curves, but no big difference. I did not expect much.