spring rates?

[xplicit]

does anyone have any test results of spring rates? like what psi = what spring rate. im wondering about 2b6's

[DJDAudio]

I have a chart.. oh man let me try to find it.
You looking for spring rate in CPM?

[xplicit]

hmm not sure what cpm is. I have a bmw 325i with 2b6's. alomost every guy on the bmw forums hates on air ride. i was hopping to find out how to figure spring rates out. so i could compair air to lowering springs or coil overs. thanks!

[DJDAudio]

Some info first,

[IMG]Spring Rate is the amount of weight needed to compress a spring a certain . Springs are rated in LB/in (in metric system kg/mm), or specifically, how many pounds of weight are required to depress the spring by one inch. To convert LB/in to kg/mm international, you must divide divide figure by 56.

Consider you have 2 springs having different spring rates: One with 345 g/mm and the other with 480 g/mm. So what does it mean?

It means the 1st spring will compress 1 mm if you put a load of 345 grams, while the 2nd one will not. The 2nd one will need a 480 g. load to compress 1 mm. According to this, we can say that the 2nd spring is harder than the 1st one, or we can state that:

Springs that have a low Spring Rate are soft, while springs that have a high Spring Rate are stiffer.



If there are 2 different values listed, it means that the spring starts at one rate, and ends at another rate under full compression.

For example: a 10lb to 25lb progressive spring will need 10lb to compress it the first inch, then 13lb the next inch, and so on, until the end of the travel; it will take 25lb to compress it the last inch. The benefit of this is that the spring can be soft enough at the start of the travel to offer a soft ride yet be stiff enough at the end of the travel to performance well during hard braking and turning.[/IMG]

[DJDAudio]

More on air springs

http://www.firestoneindustrial.com/p...ng%20works.pdf

[DJDAudio]

"For example, in an application designed to use either coil springs or air springs to support loads ranging from 1500 lbs [6.67 kN] to 3000 lbs [13.3 kN], a system using a coil spring 8.5 inches [216 mm] tall with a constant spring rate of 1200 lbs per inch [210 kN per meter] would have a natural frequency ranging from 118.9 cpm at 3000 lbs [13.3 kN] to 171.6 cpm at 1500 lbs [6.67 kN]. For the same loading, a system using a style 20-2 Airmount® isolator would have a natural frequency with a range from 95 cpm at 3000 lbs [13.3 kN] to 103 cpm at 1500 lbs [6.67 kN]."