Big wheels used forSmall wheels used for
It is up to the designer of the coaster whether the ride needs small or large wheels. Size adjusts the speed that the coaster will go by how much weight friction it has on the tracks. Most times, the designer has to change the original wheels during tests to ensure that the ride hits the targeted speed that they intended.
The big wheels are called running wheels, as they are what the cars ride on as they traverse the track. There's two sets of smaller wheels: the guide wheels and upstop wheels. The guide wheels are situated perpendicular to the running wheels, either on the inside or outside of the track rails, to keep the cars centered on the track. The upstop wheels are underneath the track rails to keep the cars from lifting off the track.
