OEM rear spring rates

[John Kat]

I was curious to compare the spring rates of some of my Suzuki's.
To do so, I used the following formula:
k=G*d(pwr4)/8*D(pwr3)*n
k is in Newtons per mm
G is a constant ( 84*10pwr3)
d is the diameter of the wire in mm
D is the diameter of the coil
n is the number of free turns of the coil

To make it meaningfull to the US community, I converted the results in pounds per inch
GS 1000 skunk ( 1978) 130 lbs/inch
GS 1000 ST ( 1981) 116 lbs/inch
GS 1100 SD Katana 170 lbs/inch
For comparaison purposes the official rate for the Kawasaki KZ 1000 (1978) is 125 lbs/inch
No wonder the Katana will shake you to pieces

[Guest]

I was curious to compare the spring rates of some of my Suzuki's.
To do so, I used the following formula:
k=G*d(pwr4)/8*D(pwr3)*n
k is in Newtons per mm
G is a constant ( 84*10pwr3)
d is the diameter of the wire in mm
D is the diameter of the coil
n is the number of free turns of the coil

To make it meaningfull to the US community, I converted the results in pounds per inch
GS 1000 skunk ( 1978) 130 lbs/inch
GS 1000 ST ( 1981) 116 lbs/inch
GS 1100 SD Katana 170 lbs/inch
For comparaison purposes the official rate for the Kawasaki KZ 1000 (1978) is 125 lbs/inch
No wonder the Katana will shake you to pieces

Aye aye...I didn't know we had to do math here....

[salty_monk]

This works great for those without a calculator... I used it to plot how I would cut my springs to get the required spring weight for the forks.

http://www.pontiacracing.net/js_coil_spring_rate.htm