To avoid becoming a victim of bike theft, every cyclist should have a sturdy bicycle lock as standard equipment. The only question is: Which lock is the best?
Leaving aside all the very cheap locks that are basically useless, there are six different types of locks: cable and coil cable locks, U-locks, foldable locks, reinforced/armored cable locks (Steel-O-Flex) and frame locks. How exactly do these lock types differ? Here is a brief summary:
Heavy U-shaped steel bars are the best bicycle security you can get. Today's branded products are so strong that an attempt to force them open on the road has very little chance of success. However, only the best models usually provide protection against the lock being "picked" professionally. The higher investment is worth it: if you are willing to spend a lot of money on your dream bike, the extra expenses to protect it seem rather small.
Chain locks are a very good choice when flexibility is a priority. Although being very flexible, chain locks are made of solid material and are therefore extremely resilient, especially against small cutting tools frequently used by thieves. To maximize your locking options you should not opt for the shortest length available. Chain locks often make it possible to secure not only the frame, but also a wheel or other valuable parts of the bicycle.
So-called foldable locks combine the flexibility of chain locks with the same level of security and strength of a U-lock. They can be folded up into a compact size like a folding rule and fixed easily to the bicycle, especially using one of the special carrying bags that ABUS supplies with all of its locks. They come with a flexible touch fastener or can be attached to the bottle holder. Tip: choose the longest model available so that you don't have difficulties when locking the bike to a street lamp.
Frame locks alone are not sufficient to protect against theft, but they have their place as “immobilizers”. It may be enough to lock the rear wheel if you can keep an eye on your bike while paying a quick visit to the corner shop. Chains and cables that can be connected directly to the frame lock are available as accessories for several models. This is a very good way of increasing security to a higher level. In other cases, they are suitable as an additional lock in combination with a reinforced cable or U-lock and have the added benefit that the rear wheel is also protected against theft.
The same applies to thin spiral cables as to frame locks: they do not offer enough protection to allow you to leave the bike unattended. In this case, the locking mechanism is less important since a cable cutter is usually all that is needed to cut through the cable.