The idea behind the Super Muscle System is a suspension damping design that is able to be both plush and firm in a way no other system can. The design stemmed from always having to compromise on between square edge compliance and big hit control.
Typical shim-piston designs only allow a system to work efficiently in partial ranges performance and control. When tuning the suspension to be plush over square edge bumps, shim systems must be soft, allowing the suspension to blow through the stroke on larger impacts. Unfortunately, this in turn causes the suspension to bottom out hard and often. If the shim stack is tuned to hold up for g-outs and large impacts, the result is unwanted harshness potentially causing the rider aches and pains. Shims also tend to warp over time causing damping changes that affect the performance, most notably at low speed movements where shims don’t hold a tight seal anymore.
Blow-off valves have been employed by many tuners and OEM manufacturers with only minor improvements found over basic shim and piston designs. Blow-off valves allow the entire system to release pressure when a sharp spike like a pothole is encountered. However, this usually causes cavitation in which the rebound and traction are tampered with. The downside is that this allows uncontrolled compression, allowing the suspension to blow through the stroke and lose traction. Additionally, blow off valves create a speed range limitation. As long as a rider holds one speed over one style of bump, they will have consistency. Change or ride/drive more aggressively and the damping character runs out of tune capability quickly. Keeping brand new shim stacks will widen the usage area, but the rider would need to replace them after every ride to keep the edge like pro racers do.
Spool valves are a much newer damping technology but they are a minor advancement over shims. This expensive valve provides damping curves that mimic shim stacks and offers no performance advancement other than a more consistent design. Adjustment for damping curves requires replacement parts as they rely heavily on port shapes and sizes.
Cone valves are slightly similar to spool valves. By replacing shims, they become more consistent from a manufacturing and longevity standpoint. Cone valves generally feel like a shim stack with a blow off. They feel plusher over harsh bumps but tend to blow through the stroke and use up their travel while not being as detailed over chatter.