Bicycle lighting Power supply Types
There are three main types: hub dynamos are built into the front or rear wheel hub, and are generally the most efficient; bottle dynamos attach to the seatstay or fork and are rotated by a small wheel in contact with the tire sidewall, they are generally easiest to obtain and cheapest while European-designed tyres generally feature a raised “track” to run the generator’s wheel; bottom bracket dynamos bolt between the chainstays behind the bottom bracket and are powered by a roller against the tyre, these are easy to fit and do not wear the tire sidewall. A fourth type is a spoke-mounted electromagnetic system.