Obscure question about early front sway bars.

[moneymanager]

Porsche used a thru the body link sway bar thru 73 then switched to a "simplified" version in 74. Because the leverage on the arms is different, Frere points out that the bars can't be compared on basis of size directly. Does anyone happen to know how they actually do compare? For example is an 18mm "simplified" bar the same as a 15mm thru the body bar?

[Steve@Rennsport]

Jim,

The late 18mm bar is about the same effective stiffness as the 15mm TTB one.

[moneymanager]

Thanks Steve. I've been going around for the last three years thinking I had a stronger bar in the front than I do! Maybe that's where my oversteer is coming from.

[ossiblue]

Originally Posted by moneymanager

Porsche used a thru the body link sway bar thru 73 then switched to a "simplified" version in 74. Because the leverage on the arms is different, Frere points out that the bars can't be compared on basis of size directly. Does anyone happen to know how they actually do compare? For example is an 18mm "simplified" bar the same as a 15mm thru the body bar?

Great question! Never thought about the leverage factor. This is what makes this board so great and the amount of knowledge available so vast. Thanks for the question Jim, and thanks for the answer Steve.

[moneymanager]

Steve's answer makes sense. In 73, the S came with 15mm sway bars front and rear. In 1974, the basic Porsche came with a 20mm bar in front and an 18mm at the rear. Using Steve's ratio, that "simplified" 20mm front bar should be equivalent to an older thru-the-body bar of about 16.7mm, call it 17. So the 74, on an equivalent basis, effectively had a 17mm front bar and an 18mm bar at the rear, adding a very small amount of oversteer to what was probably a deliberately understeering car.