A bicycle parking rack, usually shortened to bike rack and also called a bicycle stand, is a device to which bicycles can be securely attached for parking purposes. A bike rack may be free standing or it may be securely attached to the ground or some stationary object such as a building. Indoor bike racks are commonly used for private bicycle parking, while outdoor bike racks are often used in commercial areas. General styles of racks include the Inverted U, Serpentine, Bollard, Grid, and Decorative. The most effective and secure bike racks are those that can secure both wheels and the frame of the bicycle, using a bicycle lock.
Bike racks can be constructed from a number of different materials. Durability, weather resistance, appearance, and functionality are extremely important variables of the material of the bike rack. Construction materials include stainless steel, steel, recycled plastic, or thermoplastic. Each material has advantages and disadvantages, and each is unique in appearance from the others.
The visibility of the bike rack, adequate spacing from automobile parking and pedestrian traffic, weather coverage, and proximity to destinations are all important factors determining usefulness of a bicycle rack. These factors will help increase usage of the bike rack, and assure cyclists their bike is securely parked.
Early models tend to offer a means of securing one wheel: these can be a grooved piece of concrete in the ground, a forked piece of metal into which a wheel of the bicycle is pushed, or a horizontal "ladder" providing positions for the front wheel of many bicycles. These are not very effective, since a thief need only detach the wheel in question from the bicycle to free the rest of the bicycle. They also do not offer much support, and a row of bicycles in this type of stand are susceptible to all being toppled in a domino effect. These types of stand are known as "wheel benders" among cyclists.
A modern version is known as the "Sheffield rack" or "Sheffield stand" after the city of Sheffield in England where these were pioneered. These consist of a thick metal bar or tube bent into the shape of a square arch. The top part is about level with the top bar of the bicycle frame, and thus supports the bicycle and allows the frame to be secured. The origin of the racks was when the frugal citizens of Sheffield had to decide what to do with some old gas piping. Local cyclists suggested the cycle rack idea and two simple bends later, and a little concrete in the ground, the rack was born. At the time this was a revolution in a world of 'single-point holders' that bent wheels and offered little lockability for frames. A version of this design feature a second, lower horizontal bar to support smaller bikes (this version is also known as “A stand”), and are coated to reduce their surface hardness and to not scratch the bike's paintwork.