Bicycle Lock

Types of Bicycle Locks

The vast majority of cycle thefts are opportunist thefts. Someone sees a bike which is not secured or secured badly and take it because it’s easy to do so. This is particularly common when riders “just nip into the shop” and are away for just a few minutes. The trouble is that it takes just a few seconds for the opportunist to take a bike which is not secured. Most will ride the bike away. To prevent this type of theft you should ensure that your bike is secured in such a way that it cannot be ridden away, either by immobilising it in some way, if you will only be away for that “couple of minutes”, or by securing it to a fixed immovable object if your absence will be for a longer period of time.

There are a number of bikes stolen each year from within peoples own properties, either from sheds and garages or simply from the back yard. These thieves are far more accomplished in their skills and it takes a substantially different type of lock to prevent this type of thief from stealing your bike.

Locking devices vary in size and security; the most secure tending to be the largest, heaviest and least portable. Lesser equipment is used to deter attempts by less skilled and determined thieves. Thus like other security equipment, bicycle locks must compromise between security, portability and cost. Some are made of particularly expensive materials chosen for their acceptable strength and low density.

An alternate defense is the provision of bicycle lockers in which the whole bicycle is locked. This also safeguards equipment such as lamps, tools, spare tubes etc, against all but the most industrious thief, or one equipped with heavy equipment or power tools.

U-Lock/D-Lock
A U-lock is a rigid metal ring in the shape of the letter U. The U part of the lock attaches to a crossbar section, and for this reason they are also called D-locks. To lock the bicycle, one locks it physically to some other object, such as a bike rack securely in the ground, parking meter or a flagpole. Merely locking the bike frame to the wheel is not recommended because, although it cannot be rolled away, the entire bicycle can still be lifted and carried away.U-locks are more secure than most other kinds of locking mechanism because they are more resistant to cutting with high-leverage hand tools such as bolt cutters. However, they are still vulnerable to some types of exploit. For instance, if there is enough space for a thief to fit a jack into the U, the jack can produce enough leverage to break the lock. Like all locks, U-Locks are vulnerable to power tools. Certain Tubular pin tumbler lock U-Locks made in or before 2005 can be easily picked by thieves, so cyclists should avoid these models. A very similar type of lock, often referred to as an O-lock, or a “bike club”, is a retracting shackle lock. This lock may be more protective as it does not leave space for thieves to insert tools like a car jack which would burst a normal u-lock.

Chain
A chain lock is a lockable chain. It often has a key or a combination lock attached to it. A long enough chain can pass through both wheels, the frame and attach the bicycle to an immovable object.
Chains vary widely in their security level. If the chain is made from basic iron or steel, perhaps bought from a hardware store, it can easily be cut with a relatively inexpensive pair of bolt cutters. Chains specifically designed for locking bicycles are also available. These chains are made of a much harder steel alloys and the links are often shaped in a manner that deters bolt cutters, such as with a hexagonal cross-section. A chain is also a convenient way to secure the cycle’s wheels.
A chain is only as strong as its weakest link, which may be the lock. Although a cheap keyed or combination lock would be an appropriate match for a hardware store chain, a specialized chain necessitates a specialized lock such as a mini u-lock. Many chains are far too big and heavy to be practically carried around by a cyclist, so it is common for cyclists to leave such chains permanently at a convenient location, such as near their place of work.

Cable Lock
Cable locks are in many ways similar to chain locks. Cable locks often come with the locking mechanism already permanently integrated. Otherwise, a length of cable with loops on both ends can also be used.

The main advantage of cable locks over chains is the ease of transporting them. Many cable locks are made of spring cable that automatically coils itself when released. Even a straight cable can be coiled by the user into a more manageable shape than a chain.

Simple cable locks, however, are only sufficient for use in low-risk areas. Even the largest diameter unprotected cable can be quickly cut with bolt cutters. Better cable locks such as the one shown on the right have overlapping steel jackets threaded over the cable. This can make it much harder to cut the central cable.

Many cyclists use a long cable to secure bicycle components (such as the wheels or seat) in conjunction with a bicycle lock or padlock, which can be used to secure the frame. Special strong cables are available which are made with a loop at each end continuous with the cable, which enable linking with a locking device.

Also, a common defect with cables containing combination locks allows the combination to be deciphered. This is done by peering into the grooves between the disks whilst cycling through the individual numbers on each disk, one at a time

Wheel Lock
Also called an O-lock or ring-lock, this is a low security mechanism mounted on the frame that immobilizes the rear wheel by moving a steel bolt through the spokes to prevent motion. It uses a straight or circular bolt which extends from the housing. This type of lock is common in Scandinavia, the Netherlands, China, and Japan.

An O-lock prevents riding the bicycle but does not, by itself, secure the bicycle to a stationary object. This type of lock is effective and convenient for securing a bicycle against opportunistic theft, when the bike is left unattended momentarily. It forces the thief to carry the bicycle.

The O-lock also conveniently secures the rear wheel: only locking the frame is needed, to secure both the frame and the rear wheel. Some models have an optional cable or chain that plugs in to the body of the lock to enable the bicycle to be secured as well.