The tuning that the reservoir nob does is only low speed tuning.(EDIT: I realized that things COULD have changed since I was into this stuff, if anyone has a diagram of the fox adjustable system I want to make sure its what I think it is.) Meaning, it opens or closes a small hole for fluid to go through. This effects how little bumps in the road feel since for those the fluid can travel through a little hole without causing deflection of the shim stack. When you go over a large bump at a higher speed that pushes the suspension up or down a more significant distance with more force the effect of the little hole (whether is totally open of closed) has exponentially less effect on the ride.
Picture a spatula with a tiny hole in it and move it under water. As long as you just shake it back and forth it does fine. Try to move it fast or a long distance and it is hard to do and has a lot of drag. For this movement to be as easy as the little movement you need a ton of holes in the spatula.
(on a rancho 9000 you are adjusting the same type of movement. Thats why the adjustment makes a big difference for the on road feel, but you can hit a big dip offroad and if your senses are sharp, you'll notice no difference than when the shock in on its easiest setting.)
Soooo, if you truly want a tuned ride you need to break the shock down and get the right shims in, Then you can screw or unscrew the valve for a cushier or more supportive ride as long as you understand that on bigger hits or higher speed hits the shock will act imperseptively different.
Shock gods in AZ. Geiser bros (specifically Rick), but they are so big now that it might be hard to get them to do a single shock job, or really expensive. (and even these guys contract to have a God come in to do their trophy trucks)
What I would do: give the guys at fox a detailed description of your application. If they have dialed in something pretty good, great. If not, be prepared to give vehicle weight, shock length, application, etc. and ask them to recommend a valving for you. At least then you start with something close and then you can learn to pull it apart and try different shim stacks (not recommended, without specific tools most people leave some amount of air, no matter how small, in the shock and it kills the performance because of emulsion. It only takes a couple bubbles. We used a vacuum seal to make sure there was no air in the shocks at DR.) (also dont expect the guys at SAW to be willing or have the knowledge to tell you what valving to use. Not being mean, but unless they have a lot of new employees they dont have anyone there that knows much except how to keep the manufacturing process rolling.)
Or you can use the adjuster to make some finite adjustments then. Those shocks will handle a lOT more abuse, last longer and although they WILL ride more firm its because they are an internal resivoir style(like a bilstien 5100, basically the only low level shock to have even this basic technology). (even if the reservoir is attached we still call it internal because the air pocket is internal suspended about half way through the external reservoir.)
These should not have to be rebuilt, unless you rust the shocks, get dirt in them, bend them etc for 5 or more years. There is just no way to give them enough abuse. If you ever open the shock and smell the worst smell of your life you have burnt the oil. (rotten eggs!) I've never seen anyone do this on a non race vehicle. There are things that 6 or 29 hours of pounding that will do strange things to a shock and the plastic seals inside it!!
. I am not sure if the adjustment on top of the remote reservoir does both rebound and compression? I am going to have to find out!
