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914World.com _ 914World Garage _ Want to calculate torsion bar rate

Posted by: 914forme Aug 26 2006, 08:21 PM

Okay I am brain dead here, I tried to morph the one out of Fred Puhn's Book, but then I get numbers to the 10 and 11 power in foot pounds

Any math wiz out there want to give this a try. Working hte last two days for 48 hours straight has done my brain no good.

Here is the formula it can be found also in How to make your car handel page 142.

=SUM(1,178,0*(D2^4)/L2*A2^2)

D = diameter
L is the length of the bar
A lever arm length

TIA, I am off to get some much needed rest

Take care, Stephen Jacobs

Posted by: sixnotfour Aug 26 2006, 08:34 PM

http://www.proshocks.com/calcs/torsionrate.htm

Posted by: Borderline Aug 26 2006, 09:05 PM

Stephen:

the basic fromula for a torsion bar is: angle of deflection=(torque * length)/(19691*d^4)

"Angle of deflection" is in degrees.
"Torque" applied to bar is in in-lbs.
"length" is the effective length of the torsion bar in inches.
"d" is the diameter of the torsion bar in inches.

My numbers show the stock Tbar to be about 107#/inch at the wheel.
A 22mm Tbar would be about 240 #/inch at the wheel.

Hope this helps

Posted by: 914forme Aug 27 2006, 11:46 AM

Yeah the caclualtion works

I forgot to change the 19mm into inches

A 19 inch Torsion bar on a 914 will produce numbers to the 10 and 11 powers.

It is times like these that make you humble.

I actually did not realize it until I went and used the on line cacluator, and it came up the same.

Thanks again guys,
Take care, Stephen