Track frames are built for single speed use with a fixed gear they are lightweight low maintenance machines which make great winter hacks, commuters or track racers. There has been a surge in popularity over recent years in single speeds no doubt due to the large amount of couriers using them, many people are adopting single speeds for commuting and training on through the winter months. A single-speed bicycle is generally cheaper, lighter, and mechanically simpler than its multi-geared equivalent. Without derailleurs or other gearing systems, there are fewer parts on the bicycle that require maintenance making this type of cycle ideal for city commuting in all weather. The drivetrain efficiency of a single-speed can be greater than today's typical multi-geared bicycles. A straight chainline, lack of chain drag from rear derailleur jockey pulleys, and lack of chainrings, ramps and pins all improve efficiency. As a single rear cog takes less space than the typical seven to ten cogs present on most multi-geared rear cassettes, rear wheels can be built with little or no dish, which is inherently stronger by virtue of the wider base in the triangle formed by the hub, spokes and rim.