^from wikipedia:
The eight spokes represent the Noble Eightfold Path of Buddhism. They are said to have sharp edges to cut through ignorance.
Other symbolisms in the eight-spoked Dharmacakra in Buddhism:
Its overall shape is that of a circle (cakra), representing the perfection of the dharma teaching
The hub stands for discipline, which is the essential core of meditation practice
The rim, which holds the spokes, refers to mindfulness or samadhi which holds everything together
The corresponding mudrā, or symbolic hand gesture, is known as the Dharmacakra Mudrā.
The Dharmacakra is one of the eight auspicious symbols of Tibetan Buddhism.
The dharma wheel can refer to the dissemination of the dharma teaching from country to country. In this sense the dharma wheel began rolling in India, then arrived in China, and then to Korea, etc.