The spring coefficient [K value] is not a constant value, but the spring in itself is featured with multiple K values.

The illustration of force and deformation correlation of conventional spring is shown in Figure 1, typically a approximately straight line. The so called spring coefficient exactly means the ration of Force/Deformation Volume: K= constant =8 .

hus, the typically rated 8kg or 6kg springs mean that the spring is featured with each 1mm deformation required for 8kg force, and the mathematic unit is .

kgf means the force unit but not a type of mass unit. In Chinese, the unit can be translated into the meaning for “how many kilograms of weight for each 1mm of deformation ?”.

Whenever the device is installed with the Rolless, afterwards, it is able to increase the K values right on the neutral point of tires. The neutral point means the balance location of back-row wheels when people sit in the vehicle.

The illustration is shown as Figure 2:

Because the Rolless is designed with excellent functions and special rubber material, it is available for users to adjust to any thickness in good response to changes of variable K values. If users adopt the Rolless with two types of various thickness combinations, the variance of K values will be much more divergent. Also, the various thickness combinations can determine the location required to change K values.

The illustration is shown as Figure 3:

The most appropriate thickness arrangement will definitely show the strongest trend of turning transition right on the neutral point. The thickness arrangement with larger variance will definitely cause later turning transition. The larger number of Rolless combinations will also cause larger degrees of turning transition. Whenever all spring gaps are fully installed with the Rolless, the spring is actually featured with the highest stiffness. At this moment, the spring is hardly damageable, because all applied forces are well absorbed by the Rolless.

We guarantee that our Rolless within quality guarantee validity is hardly damageable under correct installation, because the deluxe rubber material made into our Rolless is quite appropriately operable under the extremely tough conditions.