15 vs 16 mm rear anti-sway bar

[Neil '67 911S]

Ol' Ivory (early '67 911s) came equipped with a 15 mm rear anti-sway bar. The Rust Bucket, also a '67 911S, came with a 16 mm rear anti-sway bar. What would be the advantage of one size versus the other handling wise? Which would be preferable for a street stock 2.0 '67 911S?

Thanks!

[Flieger]

Stiffer(bigger) rear bar gives more oversteer tendancy.

You have to make the call based on driving style. Torsion bar stiffness goes up by diameter^4 so a 1 mm difference can be felt is a more lively car through the turns. The car wants to rotate quicker.

[Neil '67 911S]

Agreed on the vehicle dynamics. A big bar on the front, increases rear lateral and motive traction. A big bar on the rear, increases front lateral and motive traction.

We all know that Porsche struggled with the SWB 911 handling, which ultimately led to the development of the LWB. Ol' Ivory is 305764S and the Rust Bucket is 306066S, both '67 911S. Was the change from 15 to 16 mm a permanent change in the SWB 911S? Or was this a "parts bin" availibility issue?

[304065]

If you have too much rear bar you hit the wall backward. Too little you hit the wall forward. Simple.

[jameshtaylor]

15mm to 16mm at the rear, on a street car, will barely be noticeable...just a tad more oversteer. And if you're not going thru your neighborhood at 60mph over the speed limit, it will never affect you one way or another. 18 or 20mm on the other hand would be a noticeable change.

[RSTarga]

waht size bar do you have in front are your torsion bars stock?

[John Fusco]

Porsche recommended :

Curcuit racing : 16 F and R

Hill Climb : 14 F / 16 R (let that back end go !)

Rallies : 15 F / 16 R - that was also stock ' 67 911S.

Also recommended that the ride height be adjusted according to the type of use.

[John Fusco]

Oh, and musn't forget:

The Normal had only a front , 13 mm bar, which more than a few auto x drivers prefer as a set up.

[orange911]

I have 15 for the front and an 18 rear. Is the 18 way too much for street?

[John Fusco]

Depends on how much of the road you like to take up....

Curcuit racing is closest perhaps to spirited road runs and there the factory recs. 16.
Stock also being 16 I would guess ( I've never tried it ) 18 seems like it would be excessive

What size tires do you run ?