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Old February 5th 2003, 06:44
Tim Tim is offline
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Join Date: Aug 2002
Location: Hong Kong
Posts: 182
Hi Justin,

I've got the book "Baja Bugs and Buggies" which mentioned the torsion-bar spring rate as follows:

For stock torsion bar with 22mm diameter
21-3/4 in bar length - 588in-lb
24-11/16 in bar length - 497in-lb
26-9/16 in bar length - 464in-lb

Please note that this is expressed as torsional force in-lb, not the lb/in as of the spiral spring rate.

Because of leverage, rear suspension stiffness depends on the center-to-center distance from the torsion bar to the axle. In a stock suspension, this distance is about 16-1/2 in. To find the amount of force 1 degree of preload produces in a torsion bar, divide the torsion bar-to-axle distance into the torsion bar spring rate.

e.g. a 21-3/4" stock torsion bar,

588in-lb / 16-1/2in = 35.6lb (change 1 degree)

There are also some torsion bar rate information in the tech article "The perfect suspension" of the GL website.

Hope this helps.

Tim
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