Axles can be either driving or non-driving axles. They maintain the position of the wheels relative to each other and to the bus body. A drive axle also transmits driving torque to the wheels.
Axles can either rotate with the wheels or they can be fixed to the bus body and have the wheels rotate around them.
Bearings constrain motion to the desired motion.
This page lists suppliers who deliver axles and bearings for buses and coaches, as well as the latest product news.