Seperator Piston

Russ,
We have all types of considerations..
The less volume we have for the same rod displacement the steeper the pressure rise. That adversely impacts sag measurements (when the shock is heated), by impacting what is called the nose Pressure, rod charge, or gas springing. At the same time some tuners have used that effect to increase the effect of the rod charge above a certain rate of compression ALA The secret Enzo subtanks shown on the factory Kaw bikes of Ezra..

The larger the volume the less impacted by heat in the pressure rise relationship. (Addtion)

Diameter is the big one however, the larger the diameter of the reservoir the less the hydraulic relationship between the pressure in the reservoir and rod charge matters. So in general you could have a huge but narrow reservoir and have more impact on rod charge than if you had a wide and small volume reservoir. (Divison)

The basic constraints are fitment, and if the shock gets too big then it won't heat uniformly and that's as bad as overheating.. A shock warmer makes lots of sense when you think about it.

BR,
Jer

Russ,
Ask my buddy Shock nut abnout these babies.. While they are fun to look at and think about, techincaly you may be surprised to hear someof his coments..

Jer

Russ,

I'm getting ready to go do some ride/testing with my sled this weekend in Hurley,WI so for now you can pick up a couple comments on this in the article I wrote that Jer has on his site. Possibly near the bottom of the Part II I think. That article was dealing with snowmobile shocks/IFP etc. If you want, you can email questions and I'll look them over when I get home. I'm currently running my Fox reservoir shocks with zero nose pressure when at full extension, meaning my seperator piston in the reservoir is bottomed out at full extension. Any minute amount of displaced fluid pushes that back and we then have full charge pressure on the shock. I'm just playing with charge volumes here is all. IFP pressure rise is scary though. Very small volume at 200 psi means incredible rise. I been calling them Nuke warheads as a joke.