Firko, On my Curnutts I went to a Works style spring limiter with dual springs and small travel limit rings above the dividing collar. That allows some tuning of the spring rate through the travel. It will start out fairly soft (two different rated springs are always softer than either by itself) and when the travel limiter stops the short spring travel, it uses only the stiffer long spring. Works Performance did this with I think as many as 3 different springs stacked together to control the progressive spring rate through the travel. They had some "Trick name" for it but I don't remember what they called it back in the day! The collar between the upper and lower springs is nylon, and keeps the springs from "ringing" on the shock body also, like the full length Curnutt springs had a tendency to do. I remember guys spraying chain lube and WD-40 and such on their springs to try keeping them quiet. Charlie used 4130 tubing for the shock body and the best quality springs that he could get so they tended to last pretty well. People now say that they don't have a sophistocated damping system, but they ARE Period! And there are still people pushing up and down on them and saying that they are too soft until they actually ride with them! You can't test them with a push compression test!
Swiss