Materials
Skateboard wheels are made of polyurethane. This is the best choice because it's soft and flexible and yet durable. People are not going to risk riding wheels that would break under pressure.
In fingerboarding things are a bit different. Load is not counted in hundreds of kilograms (by landing) unless someone hits really hard. It sometimes happnes but one does feel pain while breaking fingerboard.
You can use almost everything as wheels (it is even possible to ride without wheels). Cheapest materials are pressure moulded - like Tech Deck wheels. Strong enough for a while but not the best choice.
That's why our Grand wheels are made on CNC machines from best available high quality engeneering plastics.
Materials
First of all polyamides and polyacetals - especially designed for bearings. Main features are durability, and low friction and ease of machining.
Than we have PEEK – high end material used in NASA equipment or in medical stuff. Price also high but worth it. Sooner truck gets shiny polished surface than you see scratch on the wheel.
We also experiment with some other materials (like ptfe, polycarbonates or metals).
