Wheels are usually just simple cylinders, although fans of I, Robot (2004) may have admired the handsome ball-wheeled vehicle driven by the protagonist. YouTuber [Brick Technology] decided to evaluate the use of spherical wheels with a Lego car design.
The advantage of ball wheels is that they can rotate in multiple directions when driven on different axes, with the advantage of improved manoeuvrability. With a set of drive rollers that are spring loaded with rubber bands pushing against the 52mm Duplo spheres, the ball wheels can be turned both forwards and backwards, as well as left and right. This gives the Lego car a pretty neat firing skill, as well as the ability to spin on the spot or steer in a more traditional way. The car is controlled via smartphone, thanks to BuWizz modules that allow the Lego motors to be controlled remotely.
Bullet wheels are unlikely to catch on in regular cars; the mechanical complexity required to power them makes such designs impractical for automobiles. However, omniwheels and similar designs have found some uses on forklifts and other such low speed applications where the ability to move in any direction is very useful. Video after the break.