Combination Vs. Key Bike Lock: A Fair Comparison

Trying to keep the baddies away from your bike? You are probably wondering if a combination lock will provide better security than a key lock.

The short answer is that a key bike locks are generally more secure. Many combination locks can be cracked in less than a minute by pulling on them. While it’s true that key locks are vulnerable to lock picking, those that require a cylindrical or a round key are more difficult to lock pick.  

But there’s much more to take into consideration, so keep reading to learn more.

What Is A Combination Lock?

Combination locks are pretty convenient because you don’t need keys. However, you have to remember a code; usually, a combination of numbers, to unlock it.

You can also share this code with other trusted individuals without handing them the key, which can be convenient at times. Some combination locks come with a lot of digits. And with more digits, the lock becomes more secure. There are 3 to 5 digits on most combination locks.

How do they work?

Most combination locks feature a wheel pack. This wheel pack has a set of wheels designed to work together. Of course, you have to know the combination to make them work. The combination dial is directly attached to a spindle, and inside the lock, the spindle runs right through different heels and a drive cam.

The number of wheels within a wheel pack is determined by how many numbers there are in a combination. There is a wheel for each number. A drive-in is attached to the drive cam, and as the cam turns, it eventually gets in touch with a small tab adjacent to the wheel called a wheel fly.

They have false gates

Manufacturers also understand techniques of breaking the code. Therefore, they use different measures to confuse the lock breakers, such as false gates. False gates give the thief the false impression that they’ve found the correct combination.

Types of Combo Locks:

3-ring combination locks

Combination locks with 3 rings of numbers or letters are pretty basic. There are only 720 different combinations available here. Even an unskilled thief can go through these combinations within a few minutes.

4-ring combination locks

4-digit combination locks are very common, and they have 10,000 possible combinations. So going through this many combinations can be pretty time-consuming. Thieves will likely look for other means to bypass the security these locks offer, for example by using wire cutters.

5-ring combination locks

5-digit combination locks are the most secure of the bunch simply because there is an endless amount of combinations and false gates involved.

Are combinations lock safe?

Combination locks might seem pretty difficult to crack, but for the most part they are not. You can break them apart by pulling on them as you open them. The shackle will stick on the correct numbers, and it will open.

There are many online tutorials that anyone can go through and easily unlock a combination lock. This video shows how easily you can break through a combination lock without having the right combination. Here’s another video that shows how to break through a more high-end combination lock.

These types of procedures make them a security vulnerability rather than an asset. It might provide you with a false sense of security, so you leave your bike in an unsafe area and someone quickly pulls on the lock and the bike is theirs.

What Is A Key Lock?

Key locks are not the ultimate, foolproof mechanism for deterring bike thieves, but they are generally better than combo locks.

Perhaps the most annoying thing is that you have to carry the key. And if you lose the key for a thick chain, you’ll have to use bolt cutters to get your bike moving again. But key locks typically come with a spare key, so I recommend keeping it in a safe place in case of such an emergency.

Bike key locks also require maintenance. You have to lubricate these key locks occasionally to keep them operational. I suggest lubricating the lock every 2-3 months.

Types of key locks:

Flat key locks

Flat keys are quite common, just like any regular key. They can also come in double-sided wafers. It might give you an impression of high security, but these locks, in reality, are pretty easy to break with the right tools and skills.

Cylindrical or round key locks

These tubular keys are commonly found in chain locks or high-end U-locks, but they also function like flat keys. Lock-picking this type of lock is much more difficult than a flat key lock. I personally use this bike chain (aff link to Amazon) with a round key to secure my bike (so far so good!).

Combination Locks vs. Key Locks

Generally speaking, key locks are safer. Especially a tubular/round key lock because it’s harder to lock pick. Key locks are better protected against shimming compared to combination locks.

Breaking through a key lock requires far superior skills than a combination lock. This is the sole reason why key locks are better than combination locks. But it doesn’t mean that combination locks are entirely useless. On the contrary, they also have their advantages and come in handy to secure your bike.

Let’s assess them both, and for that, we need to understand what bike locks have to go up against in general while keeping your bike secure.

With lock picks

Lock picks are bread and butter tools for thieves and they are only useful for key locks. But as we mentioned before, combination locks can sometimes be opened without any tools, just by pulling on them. Again, not all, but many have this deficit.

Wire cutters

Cutters are versatile and small and can cut through most cable locks. Obviously, the thicker the cable, the harder it is to cut through it so when in doubt, choose the thicker option.

Bolt cutters

These are heavy-duty cutters and are superior in cutting power compared to wire cutters. They can cut through most cable locks, foldable bike locks, and armored cable locks.

But bolt cutters are also pretty large and bulky, and it isn’t easy to carry them around. Their massive size can draw a lot of attention. Therefore, thieves avoid carrying such big tools with them.

Power tools

Power tools are the most heavy-duty tools used to break locks. Some modern power tools come with batteries, and they are pretty lightweight and easy to carry around. That makes them ideal for breaking locks and chains.

They are equipped with plenty of power, and they can cut through a range of different bike locks with relative ease. Under the right conditions, power tools can cut through D-locks and chain locks.

But power tools are pretty loud and need plenty of time to cut through tougher locks. They can also be difficult to use by an inexperienced person.


Is there a way to make my bike less attractive to thieves?

Yes, there are some simple ways to make your bike less appealing to thieves. First of all, you can get a more sophisticated bike lock with a thick cable or chain.

Also, make sure to park your bike on racks with a street view and security cameras. Do not hesitate to bring your bike indoors if that’s possible. You can also make your bike less attractive with some tape or stickers that will make it easier to recognize in public. Thieves don’t like to stand out from the crowd.

Can anyone cut a U-lock?

Yes, U-locks can be cut, but they need some time and the right conditions. No lock is entirely safe, and even the most premium-quality lock can be cut.

A thief might have to go with an industrial-grade bolt cutter or any other power tool, such as an angle grinder. But even with these tools, it will take a lot of time to break through such a lock, and these tools make a lot of noise.

Proper conditions also matter because you will need an uncrowded place, and you also have to work on the lock at a right angle, or it might result in injuries or bike damage.

Final Word

For the sole purpose of the comparison, the clear winner is the key locking mechanism. But you can use both key locks and combination locks together to add more layers to your security. Thieves will need more time to break through your locks, if they can do so at all. “Work” is a powerful deterrent for thieves, since they get into stealing other people’s stuff to avoid work in the first place.

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