968 M030 sway bar: Settings
 

Hi guys,

I have a question concerning the adjustable 968 M030 sway bar:
The bar itself has the diameter 19mm and three different settings. Can anybody tell me to which fixed bar diameters each settings corresponds? E.g. is the softest setting as stiff as a 18mm bar?

Many thanks in advance.

Best,

Thomas :)

I believe that is the case.

The inner hole corresponds to a 20 mm, the middle 19 mm, the outer 18 mm.

Speedy, do you remember where you obtained this information?

Let me see if I can find the direct source...

From Lindsey Racing: "... the factory 3-way rear sway bar can adjusted 7% stiffer and 7% softer..."

I don't have info on the 18, but I have it for the 16. The middle setting is twice (100% more) what it is on the 16. The softest is about 10% less, the firmest is 10% more. These are values measured at the wheel. FWIW, the Weltmeister is almost 50% more firm at its softest setting than the M030 is at its most firm.

I'm inclined to think the 18 is softer than the 19 is at full soft, as the stiffness is a function of diameter squared, but only length by the one dimension. When you look at the numbers, the stiffness/area ratio is greater for the 19 in the softest setting than it is for the 16, making me think the 16 is a slightly longer bar. If the 18 is as long as the 16, then I would expect that the 19 at full soft is still notably stiffer than the 18 is. Plus the 18 was paired with a notably smaller front bar.

Thanks, Speedy.

Harry, thanks for your insightful compare/contrast. When you say, "If the 18 is as long as the 16", by "long" do you mean from the transverse span elbow to the drop link mounting hole? And by longer, everything else being equal, that would result in an effectively softer bar?

Yeah, I'm sorry about that. Bar stiffness is a function of two things - cross sectional area, which defines the bar's modulus, and the length from the bushings where they attach to the chassis and the drop length. That defines the leverage. the longer that length, the more leverage you can put on the bar.

So from info I do have at my disposal, the 19mm bar should be stiffer, even in the softest setting, than the 18. That part is "theoretical," whereas I have actual measurements from the 16 and the 3 positions on the 19.

The inner holes are the stiffest right?

Correct.

Thanks, again.

FWIW just installed the 968 m030 in the rear of my 89 951 today. Car already had the 30 mm 968 bar up front along with 300 lb hypercoils, but rear was stock 944 m030. Set mine on middle hole initially and feels great. Need to push it around track or autox and then dial in some fine tuning. Anyone tried the lindsey m035 that is out?