A bicycle lock is a security device used to deter bicycle theft, either by simply locking one of the wheels or by fastening the bicycle to a fixed object, e.g., a bike rack.
Frame and front wheel secured
U-lock
Proper use of a Case hardened security chain and monobloc padlock to secure a bicycle.
Simple cable lock (left) and steel-jacketed cable lock
Bicycle theft is the crime of stealing a bicycle. It is a common crime due to the relative ease of reselling bicycles, which have a large second-hand market. This makes the crime attractive to those needing to obtain currency quickly, such as people with substance addictions. Bicycles are also easily accessible, often being locked up outside in public places in urban areas. Despite the developed market of bicycle locks, it is estimated that millions of bicycles are stolen every year. Thieves use a variety of methods to bypass locks, including taking advantage of bicycle owners' poor locking practices. Bicycle owners can take action to reduce the chances of theft, including utilising facilities such as bicycle lockers and parking racks.
A severed bicycle U-lock lying loose around a street sign pole in Chicago, Illinois has been apparently defeated by bolt cutters.
An attempted bicycle theft in Davis, California where the perpetrator tried to the break the U-lock with a car jack
A single bicycle wheel remains locked to a pole of a stop sign at River Park Shopping Center's parking lot in Fresno, California, after the bike has apparently been unbolted from the wheel and carried away.
