Camaro 2nd gen sway bar rates

[ks71z28]

Anyone know off hand what the rate is for a typical 1.25" sway bar on a 2nd gen?

[David Pozzi]

1042 lbs/inch, a Hotchkis bar is 1140 lbs/inch

Here's a handy calculator, but watch out it sometimes gives wrong answers if you go back and change numbers. Once you do a calc, hit the reload button to do another to be sure.

http://buildafastercar.com/tech/Sway-Bar-Rate-Calculator

Your bar:
A 37"
B 11"
C 12.5
D 1.25
= 1042


Hotchkis has an OD of 1.375"
ID of .975 I didn't drill the bar to find the wall thickness, just mike'd the flattened end and divided by two. It could possibly be .250" wall, in that case, it's 1275lbs/in

[79T/Aman]

Thanks for that link Dave makes it easy rather than pulling out the calculator, I do have an issue with their assumption that all is needed is to minus the difference of the inner solid bar rate from the outer larger diameter to get the rate of a hollow bar, it does not take into account that as a roun tube is twisted it gets oval and eventualy flat (twist a straw) IMHO a hollow bar especialy a one piece with the bent ends do not put an equal twisting force on the torional center section to make these calculations accurate, furthermore the rigidity of the swing arm is never taken into account a hollow tube will flex more than a solid bar, in fact the material type is even more important here ( as those that bend tubing know the difference between bending Moly, high and low carbon steel).
All in all I feel the calculations are more accurate for a solid bar but the hollow calculations are only good for comparative purposes

[ks71z28]

Thanks Dave,

Wow that is way more than I thought 1000#!

Keith

[Rick Dorion]

Can anyone calc the rate of the new AirRide front bar?

[David Pozzi]

I think when you get rates this high, the mounts, end links, and subframe are getting a huge workout too, so even if the bar rate is as calculated, how much really reaches the wheels?

I have a hard time believing the bar is distorting into an oval, but can't disprove it either. For sure it WANTS to do it. I think the Hotchkis wall thickness is .219" I looked in a steel chart and found tube that size that is the closest to what I measured.

[79T/Aman]

well oval is not exactly the correct wording but it wants to twist like a drill bit and flaten along the twist but only in part and that is what creates weakness in hollow bars reduceing it's effectivness as more load is applied.

[David Pozzi]

I know a way to find out. :naughty:
I just need to find the time to do it.

[ks71z28]

I know a way to find out. :naughty:
I just need to find the time to do it.
Dave,

lets do it, lets twist some bars! when the rate gets super high the car leans less and the bar doesn't flex and so on and so on. I notice that my car stays really flat in the corners durring autocross, when many cars really roll or weight transfer. I tried adding a bit of roll to the chassis to try and plant the outside tire harder, but the car reacted slower and resulted in push. I really like having front and rear adjustable bars. I shortened the front arm by 1/2" and the rear by 3/4" and the car was much more resposive, especially at low autocross speeds (20-50 mph) I have dialed in the 30 year old suspension kit pretty well (Rancho Challenger III) but new changes are coming!