I plan on running a dual rate setup on my ProX and on my dads 04 XC SP.
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 ?

I run the kit on both my sleds. Poo offered also. You can fine tune the front end exactlly as you wish. The 1/2 spacers adding or subtracting. the thing works great.

So you used the 4"/9" spring set up ? Do you know what spring rates you used ? I'm kind of looking for a baseline starting point.

4'', 120 lb --- 9'', 120 lb works pretty good for all round trail on the prox
4'', 120 lb --- 9'', 140 lb not great on stutter bumps but better if you start getting into a lot of air.


The prox does not need to run as much spring as a edge .The prox shock is more upright, the edge is layed down.

Edge chasis.

4'' 80 lb, 9'' 180.


I use 3 spacers, depending on what suits your ride, you can try 2.

What shocks do you run?

The spacers and seperating colar from my kit are ment for fox steel bodies, most aluminum bodys are bigger in outside dia.

I run fox on my prox and edge front.

I've got RydeFX 's on the prox and I don't know what's on the Edge.

The rates I was going to run would have probably been WAY to stiff.

I was going to run a 110 4" and a 190 9" on the prox and a 100 4" and a 160 9" on the Edge.

Your setup will be good on the prox if your jumping your garage.

The 1/2 spacers and seperation colar, they have to be bigger for the aluminum shock.

fox steel body, od. 1.625''

ryde fx prox and edge shock, od. 1.750


Spacer ID on my kit 1.645