They are one of the most simplest modes of transport, but one of the most complex vehicles to ever grace the planet's surface and equally as diverse in companies, function, ride quality, price and etc. From different frame types to different components for the bike, every nut and bolt, every component has to work hand in hand or rather teeth in teeth or gear to gear in order for the bike to ride well and allow the rider to both feel the speed and enjoy the ride.
"Your legs are your engines, keep them moving,"