Deycore used to sell a kit that came with a 4 inch spring and a 9 inch spring. For these particular applications a 13 inch total is perfect. My question is why not run a 6 inch and a 7 inch spring ?

For this discussion let's use a 100/180 set up in a ProX which has 5.7 inches of shock stroke. This combo has a 64.3lb initial spring rate.

If using a 4 " and a 9" spring the 4" spring will coil bind (if no tuning rings are used) after 2.65" of shock stroke then crossing over onto the 9" spring for the remaining 3.05" of shock stroke.

same scenario but using a 6" and a 7" spring.

the 6" spring will coil bind (if no tuning rings are used) after 3.5" of shock stroke then crossing over onto the 7" spring for the remainder of 2.2" of shock stroke.

If you where trying to tune so the sled eats up the small washboard then still has enough to handle some big moguls wouldn't you want to use the majority of your suspension up on the lighter spring then save the last part of your travel for the occasional big bump ? Or would you split it evenly by using the 4" spring ?

Next part. What is too much rate and to little rate ? I know too much will be stiff as hell and not enough will not have enough ski pressure and can bottom out.

I was thinking for my Prox I would try 120/160 which has an initial rate of 68lbs. So if I was using a 4" & 9" set up the soft spring would take 180.2lbs to compress 2.65" then crossing over to the 160 which would take a additional 488lbs (total of 668.2) to fully use the remaining 3.05" of shock stroke.

Does this sound like it would be okay ?