Spring Characteristics and Force Tolerances of Gas Springs6798667 As opposed to most other types of springs, strut bracket use a built in pretension force along with a flat spring characteristic. Which means that there is certainly just a small difference in force between full extension and full compression. Since the piston and piston rod are pressed to the cylinder, volume reduces and pressure increases. This causes pushing force to increase. In conventional gas-type springs, this increase is normally around 30% at full compression. The pushing spring movement is slow and controlled. It really is just a few the gas flow involving the piston sides being permitted to pass through channels within the piston throughout the stroke. Conventional gas springs use 'hydraulic damping', involving a tiny bit of oil slowing the rate with the stroke immediately before the spring reaches full extension. Thus giving the movement a braking character at the end position provided the piston rod is in the downward direction. Force tolerances when charging with gas along with other factors mean that there could be variations in the force exerted by gas springs with the same nominal value. The nominal values apply at 20° C, the temperature of which gas charging is carried out. Remember that if the ambient temperature rises or falls, the force from the spring rises or falls depending on pressure modifications in the cylinder. As a rule of thumb, gas spring force increases by approximately 3.5% per 10° C temperature increase and reduces accordingly when the temperature falls.