These Polyurethane wheels have an amazing durability and are shock absorbent. The first step in making a wheel is to have a computer design. Tools will now carve into an aluminum puck until it looks like the first layer of the deign. This is going to be the first half of the wheel mold. The other half of the mold is now shaped. However some of these puck molds are only one structure with a pin in the center to make the cavity. Now, polyurethane liquid is poured into these molds and they are set to dry. After this they are baked for 240 degrees F for 40 minutes. The molds are now removed and they are check for how hard they are. Next they are removed from the mold and shaved down. Sometimes artistes will arrange graphic designs on a computer and print them onto the wheels. These wheels are very high in tensile strength, compressive strength, and resilience, Moldability (when it is hot). They are however, lower in ductility, malleability, formality and Sonorous.