Computer technology nowadays, makes it possible, to 'record' a once driven test track and to simulate it as often as one likes on a suitable testing facility. Perhaps the possibility of measuring the number of the piston movements during the operating life of an shock absorber will develop from this. The result should be an impressive number in favour of the wear-resistance of the piston and the cylinder wall.
The highest temperatures are developed during the damping of oscillations, when the hydraulic oil flows through the piston-valves, or in the case of twin-chamber absorbers, the foot-valves. As a valve, an internal stack of laminated discs that requires different opening forces depending on whether its movement is upwards or downwards, serves the damper. Sometimes the stack is more- and sometimes less pre-tensioned through the fastening nut. In certain twin-chamber shock absorbers the pre-tension can even be altered from the outside by turning the nut when the damper is completely compressed. The nut is held by a suitable wrench on the cylinder floor. Please, keep in mind, the additional sealing between the piston and the cylinder wall by a type of piston ring.