The Best U-Lock

U-locks (aka D-locks) are like giant padlocks that fasten around your bike and whatever you're trying to secure it to.

First developed in the 1970s by the company that would go on to become Kryptonite, u-locks revolutionized bike security by providing similar protection to chains at a fraction of the weight and cost.

If you’re only going to buy one bike lock (and maybe you should buy two), then a u-lock is usually the way to go.

Why?

Well, I think they offer the best balance between security, practicality and price!

If you're not sure about this, check out my complete guide to the best bike locks where I compare u-locks to chains, cables and folding locks in much more detail.

But if you're already convinced, how can you know which u-lock is best? There’s a bewildering range of sizes, weights and prices from a slew of different brands.

The truth is: there isn't a definitive "best u-lock". The best lock for one person may be totally unsuitable for another. So you need to think about your specific needs and work through it from there.

Don't worry! It's actually pretty straightforward. And this guide will take you through a simple 3-step process to make sure you choose the best u-lock for your individual circumstances.

And then at the end, I recommend a few of my favorite u-locks according to the different security levels and sizes available…

How to choose the best u-lock for you

The best u-lock for you will fulfill two vital requirements:

1. It will obviously be secure enough to stop your bike from being stolen!
2. But it will also be practical to use on a daily basis.

This second requirement is often overlooked. But whichever u-lock you choose must be both easy to carry around and must also fit easily around your bike and whatever you want to lock it to.

This issue of practicality is most determined by how big a u-lock is, so we can divide the process of choosing the right u-lock into three simple steps...

1. Decide what security level you need
2. Choose the appropriate size of u-lock
3. Find a specific lock within your budget.

Step 1: Choose the right level of security

The easiest way to determine the security level you'll need is to answer the 3 questions in the quiz below…

Based on your answers, the quiz should recommend a Sold Secure Silver, Gold or Diamond rated bike lock (with Silver being least secure and Diamond the most secure).

Sold Secure are an independent organization that test security products to destruction and then rate those products according to how long they took to defeat. They test more bike locks than anyone else and use information from the police and insurance companies to keep their techniques up to date.

This makes them the definitive voice on how secure bike locks really are, and they provide the best way to choose the appropriate security level for our circumstances.

Note: Sold Secure have different classifications for Pedal Cycles (normal bicycles) and Powered Cycles (ebikes, scooters and motorbikes). However, there is some overlap between them, which can be confusing.

This is the way it works, from most secure to least secure:

1. Powered Cycle Diamond
2. Powered Cycle Gold & Pedal Cycle Diamond
3. Pedal Cycle Gold
4. Pedal Cycle Silver
5. Pedal Cycle Bronze

So the most important thing to remember here is that Powered Cycle Gold and Pedal Cycle Gold are actually the same.

There is another independent testing organization called ART who also test and rate locks (from 1 to 5 stars) and it can be useful to cross-check their ratings against Sold Secure, which I do in the round ups below.

Extra Security Considerations

So based on your answers to the quiz, you know you'll need either a Silver, Gold or Diamond rated lock. But these ratings are quite broad; there can be big variations in the actual levels of security offered by different locks in the same Sold Secure rating.

What I'm saying is: some Silver rated locks are more secure than other Silver rated locks! And likewise for Gold and Diamond rated locks.

And if we know which features cause this variation, we'll be better able to distinguish one lock's real level of protection from another. So let's go over them…

Shackle Thickness

This is probably the biggest determiner of how strong a u-lock is. Usually, the thicker the shackle, the stronger the lock. However, the type of metal is important too, so they should always be made of hardened steel.

U-locks with diameters of less than 13 mm could be susceptible to attacks by medium-sized bolt cutters, which some opportunist thieves do use.

Better u-locks, with diameters of between 13 and 15 mm are unlikely to be defeated by anything but the biggest bolt cutters, which most casual bike thieves just won’t have.

However, some thieves will, so at the top of the range there are the thickest locks, with diameters of 16 to 18 mm which cannot be cropped by even the biggest bolt cutters.

So in terms of security: the thicker the shackle the better!

Angle Grinder Resistant Materials

Of course, even the thickest u-locks can be defeated by power tools such as angle grinders. And angle grinders are increasingly used by bike thieves in our cities and towns. But, luckily, there are a few u-locks that use angle grinder resistant materials to combat this.

Such locks tend to use ceramic composites to add a layer of security that wears down angle grinder discs as they are cutting through the locks. This slows them down and usually means a thief would need to change discs (often several times) to get through the lock.

These locks usually have the Sold Secure Powered Cycle Diamond rating (the highest possible level). And they’re usually very expensive!

But if you live in an area where thieves are using angle grinders, and you have a bike that is likely to be targeted, then these are the locks to go for. Check out the full list of angle grinder resistant bike locks here.

Shackle Locking: Single or Double?

On less secure locks, the shackle only locks into the crossbar on one side. This means that it only needs to be cut once (on either side) before the shackle can be removed with a simple twist.

Whereas, if the shackle locks into the crossbar on both sides, it needs to be cut twice (once on each side), before the lock can be defeated.

Locks that only lock on one side are also much more susceptible to leverage attacks. And since this is the most common form of attack with lower security u-locks, it's really important!

In leverage attacks, a length of metal (often a piece of scaffolding pole or a long crowbar) is inserted into the space within the u-lock and then twisted, usually using the thief's weight for maximum force...

With locks that only lock on one side, eventually the other side of the shackle will pop out under a leverage attack. Locks with double locking shackles can also be defeated with leverage, it's just much more difficult.

So remember: double locking shackles are more secure than single locking shackles!

That Extra Cable Lock!

Many u-locks, (including several of the locks on this page) come with an extra length of braided cable with a hoop at each end.

They can be used in conjunction with the u-lock so that while the lock secures the frame and one wheel, the cable secures the other wheel.

The cable is very light (and cheap). So you can secure the most valuable parts of your bike without adding too much weight (or cost) to your u-lock.

In reality, these cable locks offer very little practical protection. A thief with a small pair of hand held wire cutters can snip through the cable as easily as scissors cut through a piece of string. And all bike thieves carry such a tool.

So they only protect you from the most casual of thieves. I certainly wouldn't depend on them to protect valuable wheels with quick release levers anyway.

What's more, these cables are not so easy to gather up and carry around. You have to coil them up and then tuck them into a bag or around the u-lock. I find them a real pain. I talk about better options below.

Internal Locking Space

In the first video above, the thief had to insert a metal pole into the space within the u-lock before he could start his attack.

And it's not just poles and leverage attacks that work this way. Hydraulic bottle jacks must also be inserted into the space inside a lock in order to break it open…

But the point is: if they can't fit their tools inside the lock, they won't be able to defeat it with these methods.

And this is where the internal dimensions of a u-lock are important. The less space there is, the less room there is for foreign tools that can be used to force the lock open.

So smaller locks are more secure, right? Well, sort of. Smaller locks do have less internal space. But you can still leave plenty of room for an attack tool if you fasten a mini lock around your top tube.

And if you fasten a larger lock around your frame, a wheel and a pedal you can make sure that there's no spare room!

So it's actually more about locking technique than the inherent security levels of different sized locks. But you should be aware of this factor when you decide which size of lock you need and how you'll use it.

Step 2: Choose the right size u-lock

There are a number of factors that will determine which size u-lock you should go for:

1. Whether it's a primary or secondary lock
2. How you'll carry it around
3. What type of bike you ride
4. Where you usually lock your bike

Is it a primary or secondary lock?

A primary lock is responsible for making sure your frame's not stolen. So it normally needs to be big enough to go around your frame, one wheel and whatever you're locking your bike to.

A secondary lock is only responsible for making sure the other wheel isn't stolen. Since it only needs to go around one wheel and the immovable object (or one wheel and the frame), it can be significantly smaller.

So, if you use both a primary and secondary lock, you're protecting your frame and both wheels.

But do you really need two locks? Well, not necessarily. Wheels that are attached to your bike with quick release levers or regular nuts are very easy to steal. And I'd recommend that you take some measures to prevent that...

Normally that would be a secondary lock. But there are other options (one of which is the cable lasso I mention above).

None of the alternatives will be as secure as secondary lock, but they may be sufficient. And if you only need to carry one lock, you'll be saving a lot of weight!

What type of bike will it secure?

Different types of bike have different size frames and tires. And this will affect which size u-lock is appropriate for you.

So if you ride a fat tire bike, an electric bike or even a mountain bike, you'll have wider frame tubes and thicker tires. There's also likely to be a bigger gap between the wheel and the frame. All this means you'll need a longer, wider u-lock to fit everything inside it.

Whereas if you ride a road bike, a city bike or even a hybrid, you'll have thinner frame tubes that have less space between much thinner tires. So you'll be able to get away with a much smaller u-lock.

It's a good idea to measure the distance around your frame and wheels to make sure that you get a u-lock that fits. And don't forget, it needs to go around an immovable object as well!

How will you carry your u-lock?

How you'll carry your u-lock is to a large extent determined by the size and weight of the lock and the quality of the frame mount that usually comes with it.

The frame mount is normally a plastic bracket that fixes to the frame of your bike, into which the lock clips while you are riding around.

Depending on what type of bike you have (and what other accessories are attached to your frame), the mount can usually be fixed in a number of different places, including the top tube, the seat tube, the down tube or even the seat stays or handlebars.

Unfortunately, it's difficult to design a universal frame mount that will fit every bike and hence many cyclists complain about their performance, especially those that come with the cheaper locks.

A good frame mount should fix securely to your frame and hold the lock tightly so it doesn’t move about while you are riding.

However, there are many reports of mounts that are difficult to attach to the bike, not tight against the frame and unable to prevent the lock rattling about or even falling off when the bike is being ridden!

Of course, you don’t have to use the frame mount that comes with your lock. You could carry it in a bag. However, bear in mind that locks get wet and dirty and some u-locks are heavy enough to make carrying them on your back very uncomfortable.

You could also put it in your basket or clip it to your luggage rack if you have one. You can even fit the smaller ones in your pocket! The Hiplok (see below) comes with a clip that will attach it to your belt or bag.

And because many of the normal mounts are so poor, there are also lots of third party solutions. Holsters that go round your waist. Brackets that attach to your handlebars.

Or invent your own method! I just thread the shackle of my u-lock through my seat rails and then lock it up in between the seat stay and the seat tube.

What’s important, is that you think about how you’re going to carry it before you buy your lock.

Bigger u-locks are more difficult to carry in bags and impossible to tuck into pockets and hang from belt loops. So you're pretty much limited to the frame mounts, luggage racks or panniers.

Bigger u-locks tend to fare worse in frame mounts, too. This is because their center of gravity is further from the frame, so they're more likely to move around and work loose.

Smaller locks will obviously be easier to carry, whether on a frame mount, in a bag, slipped into a pocket or hanging from a belt. But of course they give you less locking options!

Be aware that some u-locks (usually the smallest and the biggest) don't come with frame mounts. Make sure you check before you buy.

Where will you lock your bike?

Think about where you'll normally lock your bike. Will you use public bike racks? Or will you use lampposts? Or railings? How wide and deep are these objects?

Different types of immovable object demand different size u-locks. Public bike racks are usually much thinner than lampposts, for instance. But some bike racks are thicker than others.

It's no good buying a nice mini u-lock if you routinely lock your bike to a street sign or a lamppost. It simply won't fit!

Standard vs Mini Sized U-Locks

We can divide most u-locks into two broad groups based on their size. Standard size u-locks are around 9" tall and 4" wide (23 x 10 cm). While Mini u-locks are around 6" tall and 3.5" wide (15 x 9 cm).

Standard Size U-locks

Standard size u-locks are great because they give us loads of locking options. Bike racks, street signs, traffic lights and railings are all usually accessible with a standard sized u-lock.

And whether the place you choose is empty or busy with other bikes, the generous dimensions usually make it easy to find an angle that will allow you to successfully lock your bike.

Plus, on certain bikes (mountain, fat tire, city comfort, electric etc.), if you want to lock one wheel and the frame, you'll probably need a standard size u-lock anyway.

The disadvantage of standard size u-locks is that being bigger, they're also heavier and bulkier, which makes them more difficult to carry (especially the higher security ones). Which is where mini u-locks come in...

Mini U-locks

Mini u-locks are smaller and lighter. So they're easy to slip into a bag, thread through a belt loop, shove in a back pocket or just hang from your handlebars.

Carrying a mini u-lock is much less hassle than a standard size. And even if you use a frame mount, you're less likely to encounter problems, as the reduced weight and a center of gravity closer to the frame mean they tend to remain more firmly and quietly in place.

Also, as I mention above, mini u-locks have less internal space, which makes them potentially less susceptible to some of the most common forms of attack. However, as I also mention above, this can be as much to do with locking technique as the locks themselves.

The disadvantage of mini u-locks is that they give you far fewer locking options. On many bikes, they won't fit around the down tube and the tire, so you'll need to fasten them round the seat stay and through the spokes.

And in most places you can forget about lampposts, street signs and traffic lights. A mini u-lock just won't fit around these things. So you're pretty much limited to bike racks.

Medium U-locks?

With the limitations of mini u-locks in mind, there is a growing trend for medium size u-locks. In theory, a medium lock would sit somewhere in between standard and mini sized.

But in fact, they are usually just longer mini u-locks! This means they are the same width as mini u-locks, which is much narrower than standard locks.

This is important because it means that anything wider than a bike rack is still off-limits. So no lampposts, street signs or traffic lights with most medium u-locks either.

However, you will get better angles in the bike rack. So locking your bike will be easier, and you may be able to get the lock around your tire and your down tube where otherwise you wouldn't.

Beyond medium locks, there is a great deal of variation in sizes, especially between the different brands. And there are wider or taller variations of the same models as well. So you should be able to find one that meets your requirements exactly...

Step 3: Choose the right u-lock for your budget

So you know what security rating you need and how to judge the different levels of protection within that rating.

Hopefully you know which u-lock size will suit the type of bike you ride, the places you'll lock it, the way you'll carry the lock and how you want to use it.

Now it's time to choose a specific lock that matches those requirements. You could take a look at the u-locks in my extensive lists of Sold Secure Diamond, Gold and Silver bike locks.

Or you could browse this exhaustive list of every lock I could find, and filter for u-locks.

On all four pages you can compare the weights, lengths and widths of the locks to find one that meets your needs exactly. And if you click through, you can compare the different prices.

How much should I spend?

There are huge variations in the price of u-locks. And the price doesn't always relate directly to the level of security they provide. Indeed, there are plenty of very cheap, high security u-locks!

But be careful: one of the biggest problems that we have with all bike locks is reliability. There are so many complaints and queries about jammed, impossible to open bike locks that I had to write an article about it…

Cheap bike locks are generally made with poor quality components that will not stand up to prolonged exposure to outside weather conditions. They will corrode, and then they'll stick, and you won't be able to open your lock.

It's much better to spend a little more than you'd like to on a decent quality lock than to buy a budget lock that stops working in a year or so, causing unknown stress and forcing you to buy another one. It's also the greener option!

Of course, not everyone can stretch their budget, so if you're forced to buy a cheaper lock, then make sure you clean and lubricate both the mechanism and the ends of the shackle frequently.

More details about how to avoid and fix jammed bike locks here. And some of my favorite budget bike locks here.

But if you keep reading, I recommend my three favorite u-locks for a variety of different budgets in each security and size category …

The 3 Best High Security Standard Size U-Locks

For maximum security, I have chosen two angle grinder resistant bike locks. But I have also added one budget high security lock, in case you just can’t afford the high prices of the other two.

1. Litelok X1

Not only is the Litelok X1 a fantastic u-lock, it’s also my current pick for the best overall bike lock in 2024. And that’s because if your bike needs protecting from angle grinders, then the Litelok X1 offers the best balance of security, price and usability.

Yes, there are bike locks that take much longer to cut with an angle grinder (the Litelok X3, Hiplok D1000 and DX1000). But these locks are also much more expensive, and either much smaller or much heavier.

The Litelok X1 is just slightly smaller than a standard size u-lock. But it’s close enough. And it’s also about the same weight as a standard size u-lock (lighter than some, heavier than others).

In fact, it looks and feels much like any other high security standard size u-lock. Except while they can all be cut through in seconds with an angle grinder, the Litelok X1 is protected by a ceramic coating which makes this much more difficult.

In my tests it took, over a minute to cut one side, and I couldn’t even cut the other side as the lock kept moving around, increasing the wear on the discs, so that I destroyed them all before I could defeat the lock!

The most important point is that to defeat this lock, a thief is going to have to change angle grinder discs at least once. And the vast majority of bike thieves just won’t be prepared to do this in the street.

And it’s not even that much more expensive than a regular high security u-lock (check price here)!

It also comes with a decent frame mount, a neoprene pouch, and the optional extra of a belt holster, so you should be able to find a way to carry it that suits you. Read my full Litelok X1 review.

2. Litelok X3

If you’re worried that the Litelok X1 doesn’t quite provide enough angle grinder resistance, then it has a big brother, the Litelok X3.

In my tests, it took me more than 3 times as long to cut one side of the Litelok X3 (as the Litelok X1). And in total, it took 5:30 min and 4 discs to get through both sides of the X3, making it the most angle grinder resistant lock I have tested!

So if you’re looking for the most secure u-lock you can buy today, then this is probably it! 

Although to be fair the Hiplok D1000 and DX1000 took less time to cut but used more discs, so in reality they are probably about the same!

The Litelok X3 provides the same internal locking dimensions as the Litelok X1, but it is a bit more bulky overall. And it’s a lot heavier too, weighing 2.09 kg (4.60 lb), which is about the same as 5.5 cans of Coke.

However, the Litelok X3 does come with a really good frame mount, which you can attach to multiple places on your bike and keeps the lock very secure and silent while you’re riding around. So you might not notice the extra weight so much.

You will notice the extra cost through! The Litelok X3 is much more expensive than it’s little brother (check price here).

But it’s cheaper than the Hiplok DX1000 and bigger than the Hiplok D1000, so for most people this is the best choice if you are looking for maximum protection. Read my full Litelok X3 review.

3. OnGuard Brute Standard

If you’re balking at the prices of the two angle grinder resistant bike locks above, but you nevertheless need a high security lock, then the OnGuard Brute Standard is a great budget choice.

It’s OnGuard's most secure, standard sized u-lock, boasting a 17 mm shackle with quadruple deadbolt locking and a Pedal Cycle Diamond rating from Sold Secure.

Like all high security u-locks that are not equipped with ceramic compounds, it can be cut very quickly with an angle grinder. But it doesn’t matter whether the lock is from Kryptonite, Abus or anyone else. They all last seconds.

However, that’s the only tool that’s going to beat the OnGuard Brute. In fact, here’s a great video of it defeating a hydraulic bolt cutter!

If the Brute seems a little heavy then there is a lighter option, the OnGuard Pitbull Standard [Amazon] which has a narrower 14 mm shackle but retains the Sold Secure Diamond rating. The Pitbull won’t defeat the hydraulic bolt cutters though!

The real advantage the Brute has over its rivals is in the price. At around half the price (or less), as similar locks from Kryptonite and Abus, it’s an absolute bargain!

The after sales service may not be as good as Kryptonite. The build quality isn’t as good as Abus. And OnGuard locks usually need a little more care and attention with regular cleaning and lubrication.

But the slider keys make OnGuard locks much easier to use than Kryptonites. And the OnGuard Brute has been my primary lock for 2 years, left outside all day and night, all the time, and still works perfectly

So, if like me, you don’t need angle grinder protection (because thieves don’t use them where I live), but you’re looking for the ultimate in practical protection at a budget price, the Brute Standard [Amazon] may be the best u-lock for you.

The 3 Best High Security Mini U-Locks

These locks are smaller and easier to carry than the standard size u-locks. But you won't get so many locking options. In no specific order...

1. Hiplok D1000

If you do need protection from angle grinders, but you don’t need a full size u-lock, then the Hiplok D1000 is a great choice.

Its internal dimensions are 3.62” x 6.1" (9.2 x 15.5 cm) which means it’s about the same size as the famous Kryptonite New York Fahgettaboudit Mini, and definitely a mini u-lock.

However, although it’s heavy, weighing 1.93 kg (4.25 lb), which about the same as 5 cans of Coke, it’s lighter than the Kryptonite.

And owing to the angle grinder resistant graphene composite material that it’s made from, it’s much more secure!

In my tests, it took 4:25 min and 5 discs to cut through both sides of the Hiplok D1000. And that doesn’t include the time to took to change the discs! So it is an extremely secure bike lock, only rivaled by the Litelok X3.

Price wise, it costs around the same as the Litelok X3 (check price here). It’s just much smaller.

But if you ride a slim bike in a city where you mostly use bike racks, then the Hiplok D1000 could be a better choice. Because it’s also lighter, and it’s more compact size could make it easier to carry around.

And it even comes with a free carry pouch at the moment.

So if you need that extra bit of angle grinder protection, and you ride a bike that is suitable for a smaller u-lock, the Hiplok D1000 could be the perfect lock for you. Read my full Hiplok D1000 review.

2. Hiplok DX

Hiplok originally made their name with u-locks that you can attach to your waist for easy transport (the clue’s in the name). These are basically mini u-locks with a built-in clip that you can fasten to your belt or the outside of a bag.

It’s a really basic system: just two plastic prongs. But it works really well. And for people (like me), who don’t like using frame mounts, they’re very elegant and appealing.

And of course they’re miles better than the u-lock holsters which thread through your belt, which force you to take your belt on and off every time you use them, or walk round with the holster on your belt all the time!

The DX is the basic model. There is a DXC that comes with a cable which also clips into the lock. And there is even a DXF that comes with a frame mount attachment that you can screw into the holes meant for your water bottle cradle.

In terms of the lock itself, it’s a pretty standard mini u-lock, with a double locking 14 mm shackle.

This gives it Pedal Cycle Diamond and Powered Cycle Gold rating from Sold Secure, and as long as you fill the shackle and keep it far from the ground it’s unlikely to be defeated by anything but an angle grinder.

So if carrying your u-lock on your belt or on the outside of your bag sounds appealing, and you're OK with a mini u-lock, the Hiplok DX is an ideal solution. Read my full Hiplok DXC review here.

3. Seatylock Mason 140

The Seatylock Mason 140 is one of the lightest Sold Secure Diamond u-locks you can buy. In fact, the only u-lock that is lighter is the Master Lock Mini 8278 EURDPRO.

However, the Master Lock has an annoying and completely unnecessary, bulky plastic casing that significantly reduces the internal locking space of the u-lock. So I don’t recommend it at all!

The Seatylock Mason 140 only weighs 0.97 kg (2.13 lb) which is about the same as 2.5 cans of Coke and incredibly light for a Sold Secure Pedal Diamond bike lock. It is slightly smaller than the Hiplok DX, but Seatylock are also able to keep the weight down by using a clever triangular shackle.

The shackle is just 13.7 mm thick, but is able to maintain a high level of security because of its triangular shape. In fact, just like the Hiplok DX, I would say that the only way this u-lock is likely to be defeated is with an angle grinder.

The Seatylock Mason 140 comes with a decent frame mount, slider keys (which work more smoothly than the disc detainer keys used on Kryptonites), and employs a spring-loaded shackle that won’t drop out at inconvenient moments.

All these little features make the Seatylock Mason 140 just a bit easier to use than the competition.

And if you’re looking for a very lightweight Sold Secure Pedal Diamond u-lock, then you can’t go far wrong with this one. Read my full Seatylock Mason 140 review here.

The 3 Best High Security Medium U-Locks

These three locks are easier to manage than the standard size u-locks while still offering loads of options in the bike rack. In no specific order...

1. Kryptonite New-U Mini-7

This is the Wirecutter's “best bike lock” pick. And there's a lot to like about it. The 13" shackle is made from Kryptonite's top of the range max performance steel, making it stronger than some of their older u-lock shackles.

The 7" internal height will give you loads more locking options in a bike rack than any mini u-lock. For example, you should be able to get it around the tire and the down tube on many bikes.

And it comes with a steel cable to secure your other wheel. Although these cables can be cut very easily, they do provide some (mostly psychological!) protection.

It's important to note that it only has a Sold Secure Gold rating, while the other two options are Sold Secure Diamond.

For sure: the max performance steel and double locking shackle mean that the New-U Mini 7 is a high security u-lock, but the fact that the shackle is a circular 13 mm, makes it slightly less secure than the other high security options here.

However, it's a nice all-rounder that is relatively light, whilst still being very secure, and comes with Kryptonite's great after sales care.

So you can buy the New-U Mini 7 [Amazon] with confidence! Read my full, hands-on Kryptonite New-U Mini-7 review.

2. OnGuard Pitbull Medium

This medium version of the Pitbull is OnGuard's rival to the Mini-7 (although I think the OnGuard lock came first).

It's slightly wider, which potentially gives you a few more locking options. But it's still unlikely that you'll be able to secure your bike anywhere but a bike rack.

And it has a slightly thicker 14 mm shackle that is sure to be at least as strong as the one on the Kryptonite lock. In fact, it has a higher Sold Secure Diamond rating, so it's definitely more secure.

The mechanism may not be as un-pickable as it's rivals, and for sure it will need more regular cleaning and lubrication. But I find the slider keys that come with OnGuard locks much easier to use than the disc detainer keys that come with Kryptonite locks.

And the big advantage of this u-lock (like all OnGuard locks) is that you can usually find it for a much lower price than locks from the other main brands..

So if you're looking for a high-security, budget medium size u-lock, the Pitbull Medium [Amazon] is a fantastic choice.

3. Seatylock Mason 180

The first thing you notice about the Seatylock Mason 180 is the triangular shackle with a 13.7 mm diameter! This clever design keeps the weight down while effectively protecting the shackle from bolt cutters.

The Mason is just ever so slightly longer and wider than the Mini 7 so it will give you more or less the same locking options.

Like the OnGuard locks, the Seatylock Mason 180 comes with slider keys, which I find far easier to use than the Kryptonite keys which tend to suffer with misaligned discs which make them harder to lock and unlock.

And since it's received a Sold Secure Diamond rating and 3 stars from ART, it's more secure than the Kryptonite, too.

To keep the cost down, there's no frame mount supplied with the Mason. But you can buy one separately. And the mount is highly adjustable, so you should be able to find a position that works on any bike.

The Mason is around the same price as the Mini 7. And if the extra security will give you that extra peace of mind, then the Mason 180 [Amazon] is a good alternative!

The 3 Best Mid-Security Standard Size U-Locks

These medium-security, standard size u-locks will give you loads of locking options and will be easier to carry than their high security cousins.

Yes, they can be defeated by the biggest bolt cutters and certain leverage attacks, but if your circumstances are lower risk, they're a great, practical choice.

In no specific order...

1. Kryptonite Kryptolok New-U Standard

The Kryptonite Kryptolok New-U is the classic u-lock. A 13 mm shackle should defeat all but the biggest bolt cutters. And it gets a very respectable Gold security rating from Sold Secure and 2 stars from ART.

It’s really well-made, dependable and benefits from Kryptonite's renowned after sales care, which includes optional anti-theft protection up to $1500 or £800, replacement keys, and a full refund if your key breaks in the lock.

The only downside is a frame mount, which some people say doesn't adequately support their lock. However, I think this is often a case of poor installation (either through confusing or misread instructions). If it's installed correctly, it should do a good job on most bikes.

So if you’re looking for a practical bike lock for low to medium risk areas from a company that offers great customer service, the Kryptolok [Amazon] could well be the best u-lock for you. You can read my full review of the Kryptolok here.

2. OnGuard Bulldog Standard DT

The Bulldog is OnGuard's equivalent of the Kryptolok. It, too, features a 13 mm shackle, but it is less secure, receiving only a Silver rating from Sold Secure.

However, it’s slightly lighter and cheaper than the Kryptolock. And the slightly wider shackle will probably give you a few more locking options too.

OnGuard's after sales care isn't a patch on Kryptonite's. And you'll need to clean and lubricate it more often to prevent it sticking.

But it’s such a good value, if you’re looking for practical protection in low to medium risk areas at a discount price, then the Bulldog [Amazon] could well be the best u-lock for you. Read my full review of the Bulldog here.

3. Abus Granit Plus 640 230

The Abus Granit Plus 640 230 is the lightest of the 3 locks here. It achieves this my making the shackle 1 mm thinner and significantly narrower than the other locks.

However, it retains the same Sold Secure Silver security rating as the OnGuard Bulldog. So this is a good choice for those who really value weight savings without sacrificing protection.

It's true, the narrow shackle could make it more difficult to lock your bike up in certain situations. But don't forget: it also makes the lock more secure!

Like all Abus locks, it's built to last. So if you're looking for a very light, standard size u-lock that still offers plenty of protection and dependable performance for many years to come, the Abus Granit Plus 640 230 [Amazon] is a good choice!

The 3 Best Mid-Security Mini U-Locks

These mini u-locks would make easy to carry primary locks in lower risk circumstances, or very secure secondary locks in higher risk circumstances.

In no specific order...

1. Kryptonite Evolution LITE Mini-6

The Evolution LITE Mini-6 is a relatively new addition to the Kryptonite range. It boasts a 11 mm hardened MAX-Performance steel shackle that has the same strength as the 13 mm shackles of the Evolution Mini-5, Mini-7 and Mini-9.

This means it’s as strong as some 13 mm locks but a fraction of the weight! Indeed, at 1.65 lb (0.74 kg), the Mini-6 is also the lightest of the three locks here, despite having the same dimensions and security rating.

And although it’s not double bolted, you do get the famous bent foot design which makes it easier to use, 3 keys (one with LED light) and Kryptonite's optional anti-theft protection up to $2000 / £900.

Although it has the same Sold Secure rating, I do think the other two locks are likely to offer more protection due to their thicker, double locking shackles. But this is the super lightweight option.

I have been using the Kryptonite Evolution LITE Mini-6 as my secondary lock for a couple of years now. Overnight, or on long stays, it secures my front wheel. But on quick trips to the shop or pub I will use it as my only lock, with no problems.

It’s also very reasonably priced! So if you’re looking for a strong, light, good value secondary lock that could be also used as a primary lock under some circumstances, the Mini-6 [Amazon] may be the best u-lock for you.

2. Hiplok D Mini

Most mini u-locks (including the three here), don't come with a frame mount. I suppose the idea is that they're so small and light that we don't actually need one.

So people generally throw them in a bag, hang them through a belt loop, or shove them in a back pocket.

However, for many people this isn't possible. What happens if you don't have a bag or belt loops and your back pockets aren't big enough?!

Hiplok have realized this and all their locks are wearable. Their u-locks have a belt clip built into the crossbar, which allows you to attach them to whatever you're wearing around your waist. Or the outside of your bag (which keeps the inside clean and dry).

I love this idea. In fact, I tested their high security version (the Hiplok DXC), and thought it was a great lock.

The Hiplok D mini is their mid-security version and is almost the same but with a slightly thinner (13 mm) shackle. The shackle does lock on both sides, though. And the lock features a solid Silver rating from Sold Secure.

So if you don't like regular frame mounts and don't have an easy alternative way to carry your bike lock, the Hiplok D [Amazon] is a great mid-security, mini u-lock which could be the best choice for you!

3. Abus Granit Plus 640 150

This lock is simply the mini version of the Abus Granit 640 230 that I recommend above. It has the same 12 mm thick, double locking shackle and the same Sold Secure Silver rating. It's just much shorter!

The great thing about this lock is that it provides significantly more internal locking space than the other two locks without being heavier or sacrificing security.

It's much wider and taller than the Hiplok while also actually lighter! And it's much wider than the Mini-6, (and the same height), while being only slightly heavier despite having a thicker shackle.

More internal locking space means it will be easier to find somewhere you can lock your bike, and this is important with mini u-locks, as options are often limited by their small size. So every bit extra helps!

Beyond this, it displays the usual Abus high build quality, which means it will be dependable in all weather conditions and should last many years to come.

Like all Abus locks, it's not cheap! But if that extra locking space in a mini u-lock is important, and you value long-lasting quality, then the Abus Granit Plus 640 150 [Amazon] is a great choice!

Wrapping Up

U-locks are probably the best way to protect your bike in the street, offering the nicest balance between security, price and practicality.

But choosing the best u-lock for your bike is a very personal decision that will depend very much on your individual circumstances.

If your circumstances are high risk then you'll need a high security u-lock. But u-locks that offer high levels of protection are heavy and bulky.

Whether you can mitigate these drawbacks with a smaller u-lock will depend on what type of bike you ride, how you want to use the lock and where you'll secure your bike.

If your circumstances are lower risk then you'll probably be able to get away with a medium security u-lock. They're usually lighter. But you'll still need to pick one that meets your other individual needs.

If you're unsure about which security level you need, it's better to be cautious and go for a more secure option. It will give you peace of mind and if you buy a more desirable bike you won't need to upgrade your lock at the same time!

I hope this page has helped you find the best u-lock for your needs. You should also check out my article on wheel and seat security.

And don’t forget to make sure you know how to lock your bike properly too!

If you have any comments, suggestions or questions, please let me know below…

This page contains affiliate links, which means I may earn a small commission if you click through and make a purchase. You will not pay any extra. More details here.