Chakras: India has its own story of how humans are constituted as beings of Light and Energy. In Hindu metaphysical and tantric/yogic traditions and other belief systems chakras are points or knots, in the subtle human body. They are located at the physical counterparts of the major plexuses of arteries, veins and nerves. 'Chakra' in its literary sense means a 'Wheel', and when you have 'Wheels' running, you feel like on a 'Bike'. Once 'Wheels' start running for the first time, they never cease to stop.
Chakras are part of the subtle body, not the physical body, and as such are the meeting points of the subtle (non-physical) energy channels, called nadiis. Nadiis are channels in the subtle body through which the life force (prana), or vital energy moves. Various scriptural texts and teachings present a different numbers of chakras. There are many chakras in the subtle human body according to the tantric texts, but there are 7 chakras which are considered to be the most important ones.
Bicycle: Vehicles for human transport that have two wheels and require balancing by the rider date back to the early 19th century. The first means of transport making use of two wheels arranged consecutively, and thus the archetype of the bicycle, was the German draisine dating back to 1817. The term bicycle was coined in France in the 1860s.