We designed a new core last and found new core material that is stable, solid, tough, shape-stable. It can be injected in high shape precision. The core is firstly applied to the center-soft PU layer, which greatly dampens the vibrations. The outer hard layer provides low rolling resistance and low wear. Through the external - direct contact between the core and the harder PU layer, the push off energy is effectively transmitted forward. This is achieved by the fact that the bumps from the inequalities have to be damped in the range of microseconds, while the push off (even the most dynamic is in the range of tens of microseconds).
The set contains 8 wheels.