Shaft drive is an alternative power delivery method used instead of chain and sprockets. Power created by the engine rotates a shaft, which transfers power to the rear wheel through connecting cogs.
The main benefits of a shaft driven dirt bike is the low maintenance and cleanliness it provides compared to chain and sprockets. They can last a life time without the need to touch them.
However, it is not common to have shaft driven dirt bikes, they are heavier, they loose more power in the tansition process, and are more expensive to repair if they do go wrong.
It also wouldn’t be practical if this happened mid race. A chain a sprocket can be easily replaced at a relatively low cost, and it can be done track side with a small amount of tools being needed.
The only dirt bike I can think of off the top of my head to have a shaft drive is the Yamaha PW50. A kids 50cc dirt bike which has been made with low maintenance in mind.
Related Article: Yamaha PW50 – Ultimate Knowledge Guide
Shaft drive is most commonly found on BMW motorbikes. They have been using them as standard since 1923 and that is due to the low maintenance and longevity they offer.
Maintaining a shaft means making sure it is well oiled so it doesnt run dry.
Animation Of How A Shaft Drive System Works
This is a brilliant visual of a shaft drive and clearly shows you what is happening
Belt Drive
There is a third way to transfer the power from the engine to the back wheel and that is via a belt. This is very rare in modern times and although the concept still works, the hassles make it not worth it.
They are lowest form of drive to maintain, but a pain in the rear if you need to change one, as it usually entails removing the entire swing arm.
