How to Choose a Bike Lock
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Let's first delve into the details. A bike lock is a mechanical device that secures a bicycle to a barrier, pipe, or other unbreakable objects, or it locks the bicycle components, preventing it from rolling away. Bike locks are often made from steel, and sometimes from brass or aluminum. However, the latter two types are extremely rare, so we won't discuss them in this article. The main parameters of a bike lock include: thickness, length, type, and its reliability.
1. Cable Bike Locks
The most well-known and popular type is the cable bike locks. These are essentially coiled or twisted cables with a protective lock at the end. The cable itself consists of intertwined thin metal wires. In some implementations, the cable has additional protection in the form of a metal "armor".
The reliability and strength of the lock depend on the thickness of the cable — the thicker it is, the harder it is to cut or tear. The standard thickness starts at 6 – 8 mm, with the average being around 10 – 12 mm. There are more advanced models with thicknesses of 22 mm and more.
The length of the cable affects how many parts of the bicycle you can protect from theft and what diameter of an immovable obstacle it can wrap around. If the cable length is less than 20 cm, it's unlikely to be able to secure both the frame and the wheel.
A special silicone film is often applied to the cable (as well as to the frame). As steel tends to rust, a cable without protective film can quickly lose its aesthetic appeal and begin to crumble from corrosion. Regardless of the cable's thickness, the wire it consists of often has a thickness of less than 1 mm, making it susceptible to rust spots.
An equally important parameter is the type of lock. It can be built-in or combination, and less commonly, padlock. A built-in lock is opened with a key, a combination lock has movable digit combinations, like in travel suitcases. Combinations come in 2, 3, 4, and 5 digits. Note that shop models mostly use standard combinations "0000" or "1111" — after purchase, they need to be changed manually. Padlocks, as the name suggests, are inserted into special loops on the chain or cable, and they are usually keyed; combination varieties are very rare.
The reliability of a cable bike lock directly depends on its thickness and the sturdiness of the lock itself. Models with a thickness of up to 8 mm can be cut with regular cutters in just a few seconds. Products ranging from 8 to 12 mm can last for a minute or two, while models with a thickness of 18 – 22 mm can only be cut with special cutters — bolt cutters with long handles.
Regarding the lock's security, models with weak cylinders or plastic bodies can be broken with a regular screwdriver. A combination lock can either be picked or broken if the core isn't protected by metal — it's simply smashed with a hammer.
2. Chain Bike Locks
The next type is the chain bike lock. Unlike cable locks, they are made from regular chain links rather than intertwined wire. Like a cable, the chain is made from metal, with steel being used in the vast majority of cases. A chain offers higher reliability but takes up more space, might rattle, and isn't as convenient for transportation. Imagine, it’s heavier, and if the chain links are thick, it will be difficult to wrap them around the frame or seat post. Chain-type solutions can be equipped with the aforementioned padlock.
Chain bike locks are more reliable than cable locks, and can't be cut with regular cutters. However, if a thief has bolt cutters with long handles, they can cut through a steel link up to 4 mm thick in about 30 seconds or even quicker. Therefore, a chain is considered an effective protection against unprepared thieves but won't always save against a prepared one.
3. U-Lock
The third and most reliable type of bike lock is the U-shaped U-lock. It consists of a U-shaped shack made of cast steel. As already mentioned, it is the most reliable type. However, it is less convenient and pleasant to transport than the previous two versions. You can't hang it on the frame — it can only be transported in a backpack or under the seat if the lock comes with a special mount.
One of the drawbacks of U-locks is their significant weight — up to 2 kg in some models. When buying a shackle lock, don't forget to measure the thickness of the frame at the place you intend to attach it. Some locks may come with an extra cable included. These locks are more versatile and reliable but significantly increase in weight.
The U-shaped lock can be unlocked in only two ways:
- Using large cutters — bolt cutters with large handles; cutting might take up to 5 minutes;
- Using liquid nitrogen — sprayed on the shack or lock and then broken with one very strong and precise hammer blow at the freezing point; depending on the thickness of the lock and the amount of nitrogen, it might take up to 2 minutes.
4. Segmental Bike Locks
Next on our list are locks made from plates, also known as segment bike locks. These are considered fairly reliable but somewhat inferior in terms of security to U-shaped locks. Segmental models consist of sliding plates, each of which extends the entire lock when assembled. Regular cutters can't cut them, but more powerful bolt cutters can do the job. Unlike other locks, plate models are very compact when folded and easily fit in a pocket or backpack.
Foldable (segment) locks offer much more freedom compared to U-locks. In their unfolded state, they resemble an improvised chain and allow you to lock a bicycle to a tree, which is impossible with classic shackle locks (without an additional cable).
5. Other Bike Locks
There are other bike locks available on the market, for example, a wheel lock. It attaches directly to the rim — without removing it, the wheel can't turn. Or a lock for the seat post, preventing the tube and seat from being removed. However, neither of these types protect the bike from theft — a bicycle with such a lock can still be carried away and the lock can be broken in a quiet place. The same applies to disc brake locks.
Other varieties of bike locks are more likely to serve as auxiliary means, preventing wheel or seat theft from the bicycle. The bike should be secured with a more "serious" lock.
6. Comparative Table of Bike Locks
| Type | Reliability | Convenience of Locking | Transportation | Weak Points | Weight |
|---|---|---|---|---|---|
| Cable | Low | High | Convenient | Cable can be easily cut | Small |
| Chain | Medium-High | Medium | Average | Rattles during transport | Medium |
| U-Lock | High | Medium-Low | Inconvenient | Can lock the bike far from all structures | Large |
| Segment | High | Medium | Convenient | Rivets | Medium |
| On the wheel, seat post, disc brake | Low | High | Convenient | Limited applicability | Small |
7. Conclusion
It's important to understand that no lock can protect a bicycle if left unsupervised for a long period. In fact, even manufacturers point out in their instructions: if you leave your bike unguarded for more than 5 minutes, they cannot guarantee its safety. Therefore, the best and most reliable option is complete control over your bicycle. But that doesn't mean there's no need for a bike lock. Quite the contrary! A bike lock comes in handy if you need to step away for just a couple of minutes — for example, to run into a pharmacy or deliver a package, etc. It's best to park the bike for longer durations in safe places. With that, we wish you a pleasant, safe, and healthy ride.
