U-locks (aka D-locks) are a bit like giant padlocks that fasten around your bike and whatever you're trying to secure it to.
First developed in the 1970's 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 step by 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. It will obviously be secure enough to stop your bike from being stolen! 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...
Firstly, decide what security level you need. Secondly, choose the appropriate size of u-lock. And then thirdly, 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 table below...
Where do you live?
Big town, city or university campus
Small town or village
Does your bike attract second looks?
How long do you leave your bike unattended?
More than 1 hour
Less than 1 hour
If two or more of your answers are in the “High Risk” column, then you’ll need a lock that offers a higher level of protection.
If two or more of your answers are in the “Lower Risk” column, then you can probably get away with a lower security lock.
How do I know how secure a u-lock is?
The easiest way to judge how secure any bike lock is, is to look at the ratings from the testing organisations Sold Secure and ART. Both of these groups test and then rate a huge number of locks according to their security level.
Sold Secure use a Bronze, Silver and Gold rating system (with Gold clearly the most secure). While ART use a star system with locks rated between 1 and 5 stars (5 stars being the most secure).
ART seem to be more demanding than Sold Secure. For example most Silver locks only get 2 stars from ART. But I prefer to use Sold Secure as they test more locks.
So, if you're "Lower Risk" from the table above you should go for a lock that's rated at least Sold Secure Silver.
And if you're "High Risk", go for a Sold Secure Gold rated lock. I don't recommend any locks that are rated Sold Secure Bronze as I don't think they offer enough protection for any circumstances.
Extra Security Considerations
So you know you'll need either a Silver or a Gold 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 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...
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.
Can be cut by bolt cutters?
< 13 mm
Yes (medium size)
13 - 15 mm
Yes (only biggest 36 and 42")
16 mm and above
Of course even the thickest u-locks can be defeated by power tools such as angle grinders. But there is nothing we can do about that. All we can do is buy the strongest lock we can afford and try to limit the opportunities any thief will have to work on it with power tools!
So in terms of security: the thicker the shackle the better!
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 u-locks that have shackle diameters greater than 13 mm, 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 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.
Whats 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 number of factors that will determine which size u-lock you should go for including whether it's a primary or secondary lock, how you'll carry it around, what type of bike you ride and where you usually leave it.
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 either 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'd 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'll 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 which 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 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.
They 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 need to 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 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 if you want to lock one wheel and the frame on certain bikes (mountain, fat tire, city comfort, electric etc) 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 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 held 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.
This is slightly less secure in theory (but probably wont make any difference in practice)!
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.
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 maybe able to get the lock around your tire and your down tube where other wise you wouldn't.
Beyond medium locks, there is 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 the u-lock size that will suit your type of bike, 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 Gold and Silver bike locks. Or you could browse this exhaustive list of every u-lock I could find.
On all three 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 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.
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
The only way these three locks can be defeated is with power tools. And you'll never to struggle to find a place to lock your bike if you're using one of them. In no specific order...
Kryptonite New York Standard
16 mm shackle
4.35 lb (1.97 kg)
4" (10.2 cm) wide
8" (20.3 cm) high
16.8 mm shackle
4.67 lb (2.12 kg)
4.4" (11.1 cm) wide
8" (20.3 cm) high
Abus Granit X Plus 540 Standard
13 mm shackle
3.2 lb (1.45 kg)
4.3" (10.8 cm) wide
9" (23 cm) high
1. Kryptonite New York Standard
This is Kryptonite's most secure, standard sized bicycle u-lock and it boasts a 16 mm shackle with double deadbolt locking (which means it locks on both sides).
It’s slightly narrower than its rivals, which makes it more secure, but also means you'll have slightly fewer locking options. It’s also the heaviest of the three recommended locks.
But this is clearly the most secure lock of the three and it's the only one with a very impressive 4 star security rating from ART.
And like all Kryptonite's locks, it benefits from great after sales care, which in this case includes optional anti-theft protection up to $3000 / £1200.
If this one's a little heavy, then check out the Kryptonite Evolution Standard. The shackle is 14 mm which means it's significantly lighter. But it still gets a Gold rating from Sold Secure and 3 stars from ART.
But, if you’re looking for the ultimate in protection without sacrificing the number of the places you can lock your bike, the New York Standard [Amazon] could well be the best U-lock for you.
2. OnGuard Brute Standard
OnGuard's most secure, standard sized U-lock also boasts a 16 mm shackle but ramps up the locking mechanism to give you quadruple deadbolt locking! However, whether this makes it any more secure is highly debatable.
The real advantage the Brute has over its rivals is in the price. At around half the price of the New York standard and much less than half the price of the Granit X-Plus 540, it’s an absolute bargain!
Again, if this one seems a little heavy then there's a lighter version, the OnGuard Pitbull Standard [Amazon] which has a narrower 14 mm shackle but retains the Sold Secure Gold rating.
Yes, the after sales service may not be as good as Kryptonite. And OnGuard locks usually need a little more care and attention with regular cleaning an lubrication.
But if 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.
3. Abus Granit X Plus 540
The Abus Granit X Plus 540 is a bit of an anomaly. The shackle is only 13 mm thick, but because of the special steel they use and the triangular shape, it’s effective strength is equivalent to much thicker shackles. It's also double bolted of course.
This means that the lock can be lighter without sacrificing security! It's not quite as secure as the New York Standard, but it's significantly lighter than both it's rivals despite being slightly bigger.
OK, it’s also much more expensive than it’s rivals. But you get fantastic build quality with all Abus locks which means they're less likely to jam or stick as they age unlike cheaper locks.
This is my favorite u-lock and I think it's a fantastic, high security all rounder. It's size gives you loads of locking options. It's a reasonable weight. And it comes with a dependable frame mount that makes it easy to carry.
Plus the high build quality means it's unlikely to let you down in adverse weather conditions or seize up as it gets older.
So if you’re looking for the lightest u-lock without sacrificing either practicality or security, maybe the Granit X Plus 540 is the best u-lock for you.
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...
14 mm shackle
3.32 lb (1.51 kg)
3.55" (9 cm) wide
6.9" (17.5 cm) high
13 mm shackle
3.55 lb (1.61 kg)
3.25" (8.3 cm) wide
7" (17.8 cm) high
17 mm shackle
2.36 lb (1.07 kg)
3.35" (8.5 cm) wide
7.1" (18 cm) high
1. Kryptonite New-U Mini-7
This is the Wirecutter's best bike lock. 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 positions 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 2 stars from ART generally puts a lock at the lower end of the Sold Secure Gold rating; most 2 star locks are actually rated Silver.
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 on this page.
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!
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 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.
The mechanism may not be as un-pickable as it's rivals and for sure it will need more regular cleaning and lubrication.
But the big advantage of this u-lock (like all OnGuard locks) is that you can pick it for a much cheaper price than other 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 17 mm diameter! This clever design keeps the weight down while completely thwarting all 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.
And it's received the same Sold Secure Gold rating as both it's rivals. But the 17 mm triangular shackle probably makes it more secure than both of them, against brute force attacks at least.
To keep the cost down there's no frame mount supplied with the Mason. But you can buy one separately. And it's 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 a thicker shackle will give you that extra peace of mind then the Mason 180 [Amazon] is a good alternative!
The 3 Best High Security Mini U-Locks
These locks are smaller and easier to carry than the Standard size u-locks. But be careful with the Fahgettaboudit, it's heavier (and also more secure) than all the other locks on this page! In no specific order...
14 mm shackle
3.13 lb (1.42 kg)
3.55" (9 cm) wide
5.52" (14 cm) high
X-Plus 54 Mini
13 mm shackle
2.56 lb (1.16 kg)
4.23" (10.8 cm) wide
5.51" (14 cm) high
Kryptonite New York Fahgettaboudit Mini
18 mm shackle
4.55 lb (2.06 kg)
3.25" (8.3 cm) wide
6" (15.3 cm) high
1. OnGuard Pitbull Mini
There is a mini version of the OnGuard Brute Standard, with the same super strong, (albeit shorter), 16 mm shackle.
But while the Pitbull Mini's 14 mm shackle does make it a little less secure than the Brute, since it also makes it significantly lighter, I think it's a good choice for those looking for an easier to carry option.
And in fact the Pitbull has the same quadruple locking mechanism and the same Sold Secure Gold rating as it's big brother. So it remains extremely secure!
Like all OnGuard locks it's incredible value for money but needs regular cleaning and lubricating at both the lock mechanism and the ends of the shackle to keep it working nicely.
So if you're after a bargain priced mini u-lock that offers some of the highest levels of protection available, the OnGuard Pitbull Mini [Amazon] is a great choice.
2. Abus Granit X-Plus 54 Mini
The Abus Granit X-Plus 54 Mini is a miniature version of my favorite bike lock, the Abus Granit X Plus Standard.
It features the same parabolic 13 mm shackle. And it has the same Sold Secure Gold and ART 3 Star security ratings, (although it adds an impressive Motorcycle Gold rating too).
However it's much shorter. And it's much lighter. In fact it's one of the lightest high security bike locks currently available.
And while it's not cheap, the high build quality means that not only is it very secure, it's also extremely reliable.
So if you're after a maximum protection, while remaining light, practical and dependable in all weather conditions the Abus Granit X-Plus 54 Mini [Amazon] could be the right u-lock for you!
3. Kryptonite New York Fahgettaboudit Mini
The New York Fahgettaboudit Mini is the only bicycle u-lock with a 18 mm thick shackle and it's undoubtedly the most secure bicycle lock available today.
At 3.25", it’s pretty narrow. But 6 inches in height makes it the longest of the three mini locks. It’s double bolted, is the only bicycle U-lock that gets Kryptonites 10/10 security rating and is eligible for anti-theft protection up to $4500 / £2500.
However, ultimate security comes at a price. At 4.55 lbs (2.06 kgs), the Fahgettaboudit is much heavier than it’s two rivals. In fact it’s the heaviest lock on this page!
It's also quite expensive.
But if you want the very best bicycle security available today then this is without a doubt the best u-lock for you. Read my full review of the Kryptonite Fahgettaboudit Mini u-lock.
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. They can be defeated by the biggest bolt cutters and some leverage attacks but if your circumstances are lower risk, they're a a great, practical choice. In no specific order...
Kryptonite Kryptolok Series 2 Standard
13 mm shackle
2.84 lb (1.29 kg)
4" (10.2 cm) wide
9" (22.9 cm) high
13 mm shackle
3.07 lb (1.39 kg)
4.5" (11.5 cm) wide
9" (23.0) cm high
Plus 640 230
12 mm shackle
2.34 lb (1.06 kg)
3.27" (8.3 cm) wide
9.0" (23 cm) high
1. Kryptonite Kryptolok Series 2 Standard
The Kryptonite Kryptolok Series 2 is the classic U-lock. The 13 mm shackle should defeat all but the biggest bolt cutters. And it gets a respectable Silver 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.
It's important to note that there's now two versions of the standard sized Kryptolok. This one has a "bent foot" shackle which only locks on one side (hence the Silver rating).
The other version: the New-U Kryptolok Standard [Amazon] has a shackle that locks on both sides (plus other minor differences) and is rated Sold Secure Gold.
Both locks have the same dimensions, weigh more or less the same and will cost around the same price so it makes sense to get the Gold version if you can!
However the Gold version retains the 2 star rating from ART which indicates that it sits at the lower end of that rating and I'd suggest it remains a mid security u-lock.
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 and a Sold Secure Silver security rating. And it’s also slightly lighter and cheaper than the Kryptolock!
The slightly wider shackle will probably give you a few more locking options too.
However, 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. 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 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...
11 mm shackle
1.65 lb (0.74 kg)
2.75" (7 cm) wide
6.0" (15.2 cm) high
13 mm shackle
2.2 lb (1 kg)
2.75" (7 cm) wide
5.3" (13.5) cm high
Plus 640 150
12 mm shackle
1.76 lb (0.80 kg)
3.27" (8.3 cm) wide
6.0" (15 cm) high
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 3 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 light weight option.
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 (keeping 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 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 up 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 and you value long lasting quality, then the Abus Granit Plus 640 150 [Amazon] is a great choice!
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 to 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.
More Good Stuff:
Bike Wheel and Seat Locks
Win a Free Bike!
Best Folding Bike Lock