can someone help with the formulae to;

[1] calc. the effectiveanti roll bar rate {ie standard type r teg front and rear}

[2]covert from a solid to hollow bar { ie to compare a hollow bar to the above with options of changing the bar width and motion arm lenghts}

My road race teg has a custom adjustable front bar mounted in front of the bulkhead above the rack and i wish to compare the rate against the standard type r bar

The rear also has a custom adjustable bar mounted in the standard position but with different pickup positions and i wish to compare this to a mugen 26mm rear bar


[Modified by BigAl, 4:53 AM 11/5/2002]

 

In the states we call the piece of metal that goes over your head the roll bar (like roll cage)...you mean what most call a sway bar, or more correctly ANTI-sway bar...

I don't know the calculations at all, but this might make your search easier

 

twist = (2 x torque x length)/(p x diam4 x material modulus.)

courtesy of Grassroots Motorsports. You'd need to know the wall thickness of the hollow bar to determine the angle of twist for it.


[Modified by WRXRacer111, 7:58 PM 11/4/2002]

 

do a search for a post by solo-x... he figured it out and posted it....just can't remember what it was

 

thanks for that . found the formulae to calc bar rate

any idea about calculating rates for hollow bars?

 

If I recall correctly, you can treat the hollow bar as two bars. First you calculate the stiffness based the outer diameter, then you calculate the stiffness based on the inner diameter, then you subtract the inner from the outer and you get the stiffness for the hollow bar.

College was a long time ago, so I'm not 100% certain that's right, but I believe it is.