i always thought... the spring rate wasnt determined by the number of coils, rather the tension that each coil holds or the force taken to compress that spring (the kg/mm thing..) so therefore less or more coils may not detrmine the spring rate... and under enough weight the spring will compress to a maximum point... not determined by the number of coils but the tension of those coils... ie "spring rate" or force taken to compress that spring...
soooo.....if you cut a coil of a spring... your not changing the spring rate of the the coils as such... just removing a coil which will reduce the amount of force needed to compress the spring... but not because the spring rate "becomes" harder but because there is "less" spring... if ya know what i mean?
anyway... correct me if im wrong but i thought thats how it worked...