I assume you mean Spitfire brand, and no they are great. If you are concerned with weight of products, you probably need to skate for a few years more. and anyway you shouldn't even be thinking about those you should be buying RICTAS!
No
Wheels dont make a skateboard easier to turn on the skateboard trucks do that.
no
Bones wheels
yes the sizes of skateboard wheels range from 40-70 mm
yes
4
polyurathayne,
Wheels
Shark Wheels are a type of skateboard wheel that have a unique shape resembling a cube with grooves. They differ from traditional skateboard wheels in that their design claims to provide better grip, speed, and maneuverability due to their shape and pattern.
The wheels allow them to move. If you look at a skateboard it has wheels.
Skateboard companies make decks and wheels