U locks, also known as D locks, are basically giant padlocks that you can use to keep your bike secured in a safe place, either for transporting it or keeping it safe from thieves. However, no two locks are exactly the same, and it is important to remember that different locks can have their own unique properties, features, and specifications, especially if they are made by different companies.
Depending on the type of bike you own and the situations you will need to deal with, there are hundreds of U lock models out there that you will have to sort through, so knowing where to start can make it a much shorter and simpler process.
View the Best U Lock, Below.
- Via Velo Bike U Lock with Cable
- Kryptonite New York Lock Fahgettaboutit Mini
- Bell Catalyst Bike U-Lock
- Kryptonite Evolution U-Lock with FlexFrame-U Bracket
- SIGTUNA Heavy Duty Bicycle U Lock
- Kryptonite New York LS Heavy Duty Bicycle U Lock
- ONGUARD 8001 Brute STD U-Lock
- Kryptonite New York Standard Bike Lock
- Kryptonite Kryptolok U-Lock
- Abus Granit X-Plus 54 Mini Key Bicycle U Lock
1. Via Velo Bike U Lock with Cable
This hexagonal bike lock uses an all-weather design that can stand up to a huge amount of dust, dirt, and grime, as well as resisting water for better performance. Not only that, but it is relatively strong, and uses a no-hassle locking system that makes it incredibly easy to set up at almost any time with no extra tools needed.
If you prefer, you can install the mounting bracket, letting you attach the U lock to the bike directly for a much higher level of convenience while you are on the move. Each of these locks comes with two separate keys, meaning that you can keep one spare to make sure that your bike isn’t trapped forever if you lose one.
This U lock is tough, easy to use, and offers plenty of long-term durability, making it ideal for securing your bike in a wide range of different locations and situations.Check Price on Amazon ➞
2. Kryptonite New York Lock Fahgettaboutit Mini
This steel-based U lock has a special double-deadbolt design that makes it much more resistant to twisting, ensuring that it is much more difficult for a potential thief to break it without loud and easy-to-spot equipment. The disc-style body makes it far easier to drill into, as well as increasing its lockpicking resistance by a small amount.
Unlike many U locks, this design also uses a steel sleeve that covers over the crossbar, improving its durability and security even further without adding much weight. Each lock comes with three keys, giving you two possible spares that you can use if one goes missing, as well as an LED key fob that you can insert any of the three keys into.
This U lock may look fairly simple, but it is actually incredibly good at stopping thieves from taking your bike, even if they are bringing tools to make it easier for them. It can block drills, lockpicks, twist-based attacks, and even some physical bashes.Check Price on Amazon ➞
3. Bell Catalyst Bike U-Lock
This anti-theft U lock uses an 8-inch shackle that can connect your bike to all kinds of bars, fences, and posts, ensuring maximum security against common types of theft. Each one of these locks comes with not only two keys and a free key replacement service, but a $500 anti-theft guarantee from Bell themselves.
You can use the included carrying bracket to connect it to your bike, making it easier to transport and keeping it out of the way when you are on the move. Thanks to the quick-release system, the lock can be easily opened with a matching key, meaning that you don't need to struggle once it is unlocked properly.
This U lock is convenient, easy to manage, and doesn't take long to unlock with the right key but still keeps thieves from pulling it apart.Check Price on Amazon ➞
4. Kryptonite Evolution U-Lock with FlexFrame-U Bracket
The hardened steel used in the design of this U lock allows it to resist a variety of different tools, ranging from heavy cuts from bolt cutters to bashing or leverage-based attacks on the U lock itself. This is backed up by the hardened deadbolt that can also resist most common types of twisting, helping reduce the number of weak spots without opening up new ones.
The cylinder itself can also resist lockpicking and drill attempts. To ensure that everything works correctly in bad weather conditions, it has a sliding dust cover to stop jamming. Each of these locks comes with three keys and an LED fob, as well as a mounting bracket.
The amount of durability and damage-resistance built into this U lock lock makes it ideal for people who want to avoid all kinds of theft attempts, especially if they are worried about thieves who use heavier tools.Check Price on Amazon ➞
5. SIGTUNA Heavy Duty Bicycle U Lock
This incredibly heavy-duty bike U lock uses a 16mm-thick design that can protect against a massive range of damage types, allowing you to keep your bike safe while also leaving it fully accessible to anybody with one of the spare keys. Opening the lock itself is easy, but without a key, it is very difficult to break open or pick.
The heavyweight also makes it harder to smash open and will slow down a thief if they break the connected pole or fence instead. Since the cable is flexible rather than rigid, you can even double-loop it for maximum protection, or wrap it around multiple durable posts at once.
The sheer amount of durability and strength in this U lock, along with its weight, makes it perfect for turning away almost all petty bike thieves.Check Price on Amazon ➞
6. Kryptonite New York LS Heavy Duty Bicycle U Lock
Like many Kryptonite U lock designs, this model comes with the special double deadbolt that increases its level of durability against twisting attacks. Alongside this is the strong body and cable, both of which can endure a vast level of punishment from drills, bashing attacks, and leverage attempts.
The cylinder of the lock is also resistant to lockpicking, meaning that it forces thieves to try and use louder, more noticeable types of unlocking techniques. Each heavy-duty U lock comes with three keys, and the standard LED key fob, making it easier to unlock your bike in the dark without needing to hold a torch or a phone in your other hand.
This U lock design is tough, hard to crack and perfect for protecting bikes in open areas since it is very difficult for a thief to break open without attracting attention to themselves.Check Price on Amazon ➞
7. ONGUARD 8001 Brute STD U-Lock
This simple, straightforward U lock relies on tough materials and a durable design to keep your bike safe, boasting a really tough 17mm steel shackle that can endure all kinds of attacks, ranging from simple cutting and leverage to much more dangerous tool-based attempts. The co-molded design of the crossbar cover helps it handle slightly more weather damage, while the rubber coating protects the design from bumps and bashes that might wear it down over time. In addition, the X4P Quattro locking system keeps the shackle locked on all four sides, making it much more of a hassle for a thief to break open regardless of which tools they might be using.
This U lock offers plenty of durability with no real downsides, making it an excellent choice for keeping your bike safe and secure.Check Price on Amazon ➞
8. Kryptonite New York Standard Bike Lock
This tough U lock uses the same kind of hardened maximum-performance steel shared with a lot of other Kryptonite locks, as well as the same reliable double deadbolt that can make twisting attacks almost completely useless against it. The high-security disk reduces the effectiveness of drills and lockpicking tools, while the special Transit Flex Frame-U system lets you attach the lock to your bike without putting it in the way, making it easy to carry when you are on the move. Even if you don’t, and just keep it in a backpack, it is easy to set up and unlock as long as you have a key – it comes with two spares, as well as an LED fob for easier use at night.
This U lock focuses on the necessities – durability, strength, and ease of use. If you want something simple but effective, this may be one of the best U lock models on the market.Check Price on Amazon ➞
9. Kryptonite Kryptolok U-Lock
The specially hardened steel shackle used in the design of this U lock makes it extremely resistant to most forms of damage, including a wide range of hand tools, heavy leverage, or even fully-sized bolt cutters. The cable is made with a looped design to increase this even further, making it extremely difficult to crack without making a massive amount of noise. The lock comes with two keys, both of which have been designed to resist bending, breaking, and other forms of damage that might make them useless. On top of that, you also get a mounting system that can be attached to a range of locations on your bike, letting you carry the lock with you.
Durability is one of the best ways to deter thieves, and this U lock has plenty of it, even in the keys!Check Price on Amazon ➞
10. Abus Granit X-Plus 54 Mini Key Bicycle U Lock
This miniature cycling bike U lock uses a high-quality parabolic shackle to absorb and reduce the amount of force from each attack, making it far harder to break without opening up any new weak points. The special Powercell technology means that both sides of the shackle are locked separately, making it far harder to quickly break open, even with heavy tools. The keyhole has a special built-in automatic cover that keeps out dirt and debris, as well as making it more difficult to pick, and you get two keys along with a code card to help you cut more if you love them.
The small size of this U lock hides its immense strength and durability, making it great for people who don’t like to carry much while cycling but still need as much theft protection as possible.Check Price on Amazon ➞
Best U Lock Buyer’s Guide
Bike locks aren’t all the exact same design, even if many of them look very similar. There are thousands of brands, each with their own special designs and varying levels of quality, so knowing what to choose is the first step towards finding the best U lock for your own personal needs and preferences.
While it may seem strange, you need to have as much input about the U lock as possible before you actually buy anything. Even if you find two that are essentially the same, they may still have varying features: different weights, special types of theft resistance, or even just a different type of key. All of this can completely change the way the U lock works, which will also change how it performs when you are actually using it.
The Number of Locks
Many people overlook the idea of having multiple bike locks. After all, if you have two, it takes twice as long for a thief to open them, especially if they have different keys or use slightly varied designs that don’t share the same weak points. At the very least, it can delay a thief and give you more time to chase them off or call for help, and more locks might serve as an excellent deterrent to thieves who are only looking for opportunities to steal an unguarded bike.
Be aware that this won’t always be the case, though. If a thief really wants to steal your bike, and they are fully determined to get hold of it, they will eventually be able to break through if they are given enough time. In this case, having more locks won’t change much, unless it can slow them down to the point where somebody notices and stops them.
Getting more locks also costs more, especially if you are getting multiple of the same high-quality brands. In an extreme case, you might even end up spending more on the locks than the bike itself, so try to figure out where the right balance is. Remember that a broken U lock might need to be thrown away or repaired – are you willing to risk losing that money you spent on the locks if a thief is determined enough to get your bike anyway?
As you’d expect, a U lock that can handle plenty of punishment takes much longer to break with conventional tools. A weak U lock might be fragile enough to smash open with a hammer, but strong ones can sometimes even withstand power drills and large bolt cutters without snapping open or falling apart. The more durable the U lock is, the harder it is to break, which can turn away potential thieves or slow them down long enough to be spotted.
One upside of durable locks is that they are sometimes completely immune to certain forms of damage. For example, a U lock lock that is strong enough to survive being kicked might never break open, which forces the thief to use louder and more attention-attracting methods instead. This increases the chance that somebody will hear or see something suspicious and come to investigate, making it much more secure simply by increasing the amount of effort it takes for somebody to breakthrough.
Remember that durability doesn’t account for one thing – lockpicking. It is entirely possible to have a nigh-invincible U lock that can be opened with basic locksmith’s tools, so always try to consider both. Lockpicking usually takes longer than simply bashing a lock open, but it is also quieter, so a skilled lockpick can quickly open the U lock and ride away on your bike without making a sound. Even worse, the U lock will still be functional, meaning that they may be able to re-sell that too.
There is a generally-accepted rating system created by the Master Locksmiths Association that separates locks into Bronze, Silver, and Gold categories. Each of them is meant for protecting bikes in different situations, depending on the cost of the bike and/or the risks involved.
Bronze locks are the weakest. They can survive basic tools, but won’t stand up to much more than that, and can generally be broken within an hour by a dedicated thief who is willing to keep trying until something snaps or shatters. They are generally used as a ‘token amount’ of security, keeping a bike safe from people who would happily walk away, holding somebody else’s unsecured bike. However, if somebody really wants to steal it, they won’t need to try hard, so they are usually recommended for low-risk areas or really cheap bikes.
Silver locks can endure a decent level of damage from varied tools, acting as a proper level of protection against most average tools or weapons. They will still break under a huge amount of pressure, but they are harder to crack in almost every way. This makes them ideal for bikes up to around $1,000 in value.
Gold is the highest level of locks, and are generally considered to be able to withstand a full five minutes of non-stop damage from heavy tools, including giant bolt cutters or power drills. This makes them all but completely invulnerable to basic attacks, such as small hammers, but also means that they are much more expensive. If you have a bike worth over $1000, you should always have at least one of these as your last line of defense.
Related: Keyless door locks.
The best way to lock your bike is to place the lock somewhere inaccessible or awkward. For many people, this involves placing the bike on a raised surface and connecting it to something just within arm’s reach. It is still easy to unlock with a key, but thieves will struggle to break it, and lockpicks might not even be able to reach the lock itself.
Did you Know?
One of the most common mistakes bike owners make is connecting the lock to an item with no top surface. If It is just a simple pole, such as one from an old metal fence, the thief might simply be able to lift the bike off the object and ride away with the lock still connected, letting them break or pick it open in the safety of their own home.