crosspost from fb
Need some coil spring sanity check. I need a lighter spring in the rear. It's been marginal, limit strapped to about 1/2" preload, and without the spare hanging all the way off the back now, I need to lose about 2" of shaft on top of that. I'm showing about 9.5" on a 14 and want to get closer to 7-7.5. Shocks on the axle and close enough to 1:1 as not to matter.
14x175 (@10-7/8") over 16x225 (@13.5") now, that's combined rate of about 97#. Spare isn't on and will add about 60# centered over the springs.
A friend has some springs I could swap right on, but slightly odd lengths.
could do a 14x150 over 18x200, that's a little softer all around at 86# with similar progressiveness and almost certainly solves preload fully.
Corner weight math
(16[free height]-13.5[compressed height])*225[rate]/6.5[desired squat]
tells me my target overall rate is (varying inputs between compressed height of 13.25-13.5 and squat of 6.5-7) 80-95#. Longer spring gets me preloaded right. I have about 3" of thread above the spring now.