Ahh you mean shaftdriven bicycles... It use a drive shaft to transmit the torque and rotation caused by the pedal power to the wheels. These things operate at a very consistent rate of efficiency and performance, without a need for adjustments or maintenance, though lower than that of a properly adjusted and lubricated chain. Shaft drives are typically more complex to disassemble when repairing flat rear tires, and the manufacturing cost is typically higher, thus you can already ifugre it out the fundamental issue with bicycle shaft-drive systems.