keith

Was just admiring/adopting the 911 torsion bar/wheel rate tables and trying to adopt them to G50 rear bar dimensions and must not have as good a grasp on my antique math skills, as I am getting stupid numbers (spring rates with 9 zeroes, lol)

Would anyone be so kind as to run these dimensions for G50 rears?
bar length of 626mm
spline length at each end of 29mm
effective bar length, then, of 568mm

Additionally, what happens for a hollow bar? Stiffer/less stiff per diameter?

Thanks!

keith

wrong forum?

Steve Weiner-Rennsport Systems

Hi Keith:

Wheel rates between 915 & G-50 cars do not change since the springs (t-bars) sit at the same distance from the centerlines of the wheel hubs.

The same cannot be said for the 930 cars which have wider hubs that are further offset from their pivot points.

Hollow torsion bars are slightly,......slightly softer than solid bars of the same diameters. Its a very small diference.

keith

interesting. this is true even though the non-splined area of the non-G50 bar is greater (longer)?

can one assume, then, that a hollow 31mm G50 rear bar is equivalent to a 30mm solid 915-era bar?

thanks!

JackOlsen

For future Rennlist searchers:

1965-1989 spring rates, not including Turbos.

Front Torsion Bars

18.8 mm = 110 lb/in
21 = 173
22 = 210
23 = 250

Rear Torsion Bars

23 = 100 lb/in
24 = 120
25 = 140
26 = 165
27 = 191
28 = 221
29 = 254
30 = 294
31 = 332
32 = 377
33 = 427

All the information is at this link. Thanks, as always, to Wil Ferch.

keith

Jack - in that link, Wil specifically says that the tables given are for non-G50 cars - I assume because of dimensional difference in the splined-end areas?

That's what prompted my initial post...

JackOlsen

Whoops. We've come full circle, then.

You might want to put the question on the Pelican BBS, since it looks like Ferch hasn't posted on Rennlist in about three years (?).

keith

D'oh!