Originally Posted by naginalf
And, Solo, regarding that info, I'm not completely familiar with shock construction, and I'm getting confused about what's what. What is a "variable damper" and how does that work? So emulsion simply means that it doesn't have an external bladder, right. And from what I've learned of front suspension, a damper rod system is simply a piston with holes, but what is the comparable form of a "cartridge fork" for rear suspension with shim stacks? I was assuming that emulsion = damper rod, but that doesn't seem to be necessarily true. So, does the Works Ultrasport have a shim stack or holes? From what the technician there said, it was holes. I'm sure I'm oversimplifying things, set me straight here.
An emulsion shock has a single chamber where the oil is mixed with pressurized nitrogen. There is enough air (nitrogen) space in the top of the cylinder to allow for the piston rod to displace oil and not hydrolock. All the ones I've seen have a shim stack which allows for revalving. Some emulsion shocks allow adjustment of rebound damping, some do not. Reservoir shocks have the same type of cylinder as an emulsion shock but no airspace is left in the top. Instead they are connected to an external reservoir with a rubber bladder in it which keeps the pressurized nitrogen separate from the oil. In the top of that reservoir are adjustable valve(s) that control the oil flowing in. Some have a single valve which controls all compression damping, others have two separately adjustable valves for high and low speed compression damping. Because there air and oil are in contact in emulsion shocks aggressive riding, particularly offroad can cause the oil to foam thereby reducing damping effectiveness.