GMP
Active member
A midvalve, and compression base valve for that matter, is not position sensitive. Too many people say things like this about the "stiff part of the valving". There is no stiff part of the valving, there is a stiffer part of the position due to the progressive air spring effect. The midvalve, or checkplate valve if its setup like that, allows/controls the oil that is not displaced by the damper rod to flow through the rebound piston to the upper side. A lot of oil, more than the base valve flow, and can be calculated easily. If this flow is restricted too much, you have lockup and harshness, because it is all piston SPEED sensitive. A good setup will provide some resistance through low/midrange piston speeds, and then open to the point of not hindering high speed flow. This is why its called a MIDvalve. You can seup a relatively tight float midvalve with a light stack and be in good shape, as long as the stack has the ability to move and flex at a high flow rate, it will, as long as the piston ports are not a choke point. This is a real balance with the base valve as well and what good tuners get paid for. A combination of engineering theory and practical experience with different schools of thought in many cases and applications.
