Best bike locks

Securing your bike with a great bike lock will not only thwart thieves' attempts to steal your bike, but could also put them off trying in the first place. But many bike locks look similar and it can be tricky to know which ones are up to the job. 

To find out, our lab experts used bolt cutters, angle grinders and other lock-breaking tools to identify the locks that will keep your bike safe. We also checked how easy they are to transport and use, as no one wants to be wrestling with an unwieldy  lock in a downpour. 

Read on to discover the types of bike locks, to see which offered good security against even the most powerful tools in our tests and what you need to know about bike lock security ratings.

Bike insurance: what's the best option to insure your bike, how much does it cost and how you can save money

Best bike locks from our tests

Below compare all the bike locks we've tested. Click a particular lock to read our full review or scroll down to browse all our bike lock advice. 

Only logged-in members can view our full bike lock reviews. If you're not yet a member, sign up to Which? today for instant access to this and all our reviews.

A lock is only as good as how and where you secure your bike – read our tips on how to secure your bike

 Abus Bordo Big 6000

Cheapest price: £100 from Tokyobike. Also available from Amazon.

Tech Specs:

• Weight: 1,390g
• Length of lock (unfolded): 1,115mm
• Thickness (ex. plastic coating): 5mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

The Bordo Big 6000 is more than a metre long when unfolded, making it easy to secure both your frame and wheel to even a thick bike rack post.

It folds down to a compact size and even comes with a bracket to mount to your bike frame. 

But will it keep your bike safe from thieves? Sign up to Which? to see if it held up against our tough security tests.

 Abus Bordo Granit Xplus 6500k/90bk

Cheapest price: £113 from Amazon. Also available from Motardinn.

Tech specs:

• Weight: 1,745g
• Length of lock (unfolded): 810mm
• Thickness (ex. plastic coating): 8mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

The Abus Bordo Granit Xplus 6500k/90bk is built for narrow posts, frames and rear wheels. 

The manufacturer also says this bike lock provides top-level security. But will our rigorous tests strengthen this claim or grind it into the dust? 

Sign up to Which? to find out how well it performed.

 Abus Granit Citychain Xplus 1060/110

Cheapest price: £148 from Amazon. Also available from Motardinn.

Tech specs:

• Weight: 2,660g
• Length of chain: 980mm
• Thickness of chain: 10mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: No

Abus claims this is a heavy-duty bike lock with a maximum security level of 15. But did it live up to its billing when we put it through our tough lab tests? 

Sign up to Which? to unlock the full review and find out.

 Abus Granit Plus 640 

Cheapest Price: £84 from Bikeinn. Also available from Alphine Trek.

Tech Specs:

• Weight: 797g
• Internal length x width: 151mm x 83mm
• Diameter of shackle (ex. plastic coating): 12mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: No

Weighing just under 800g, the Abus Granit Plus 640 is one of the lightest bike locks we've tested. Combined with its small size, this could make it an appealing choice if you want an easy-to-transport U-lock – although there's no bike mount included.

Does its small size come at the expense of security? 

Sign up to Which? to find out how well it stood up against our expert lock-breakers.

 Abus Granit Xplus 540/160HB300

Cheapest price: £102 from Bikeinn. Also available from Amazon.

Tech specs:

• Weight: 1,660g
• Internal length x width: 295mm x 110mm
• Diameter of shackle (ex. plastic coating): 16mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

According to Abus, this is a first-class lock that will protect your bicycle when the risk of theft is high. 

It’s big, weighing 1,660g and has a thick shackle at 16mm, so it’s no surprise the manufacturer claims a maximum security level of 15. 

But do the extra heft and Abus’s confident claims mean that it will survive our rigorous tests? Sign up to Which? to find out.

 Abus Steel-O-Chain 8807k 

Cheapest price: £40 from Amazon and Mantel.com

Tech specs:

• Weight: 1,560g
• Length of chain: 1,200mm
• Thickness of chain: 7mm
• Type of locking mechanism: Automatic locking
• Number of keys: 2
• Bike mount included: No

This is a square chain lock that Abus claims is extremely versatile and can be used on almost any object. 

With a thickness of only 7mm, it’s one of the thinnest chain locks we’ve tested. But does that mean it will be easier to break into? 

Sign up to Which? and read our review to find out. 

 Abus Ultra 410/170HB230

Cheapest price: £40 from Merlin Cycles. Also available from Wiggle. 

Tech specs:

• Weight: 940g
• Internal length x width: 230mm x 110mm
• Diameter of shackle (ex. plastic coating): 13mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

Abus claims that this lock is a great fit for those looking to protect their high-end bike in areas of high theft. But it’s fairly light, weighing less than 1kg. 

Is it strong enough to pass our lab's tough tests? 

Sign up to Which? to find out.

 Axa Fold Lite 100 

Cheapest price: £51 from Amazon.

Tech specs:

• Weight: 644g
• Length of lock (unfolded): 970mm
• Thickness (ex. plastic coating): 6mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

As its name suggests, this lock doesn’t weigh much and is the lightest we’ve tested. The manufacturer suggests that it’s suitable for those who use their bike every day and lock it in low-theft areas. 

Does its lighter weight mean it's more susceptible to being broken? 

Sign up to Which? to find out.

 Axa Fold Ultra 90 

Cheapest price: £91 from Bikeinn. Also available from Amazon.

Tech specs:

• Weight: 1,428g
• Length of lock (unfolded): 810mm
• Thickness (ex. plastic coating): 8.5mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

According to Axa, the Fold Ultra is a high-quality folding lock designed specifically for bikes that require long-term security in busy areas where there is a high risk of theft.

Its dimensions are intended to make it versatile and compatible with narrow posts, frames and the rear wheel.

To find out whether the Fold Ultra lives up to its claims, sign up to Which? and access the full review.

 Axa Newton Pro 190

Cheapest price: £45 from Triton Cycles. Also available from Fawkes Cycles

Tech Specs:

• Weight: 1,382g
• Internal length x width: 190mm x 102mm
• Diameter of shackle (ex. plastic coating): 14mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

The Axa Newton Pro 190 is a full-sized, mid-weight U-lock that comes with a bike mount for ease of transport when cycling. 

But what really matters is whether it will protect your bike against a determined thief. 

Find out if our expert lock-breakers managed to crack it – sign up to Which? to see our lab test results.

 Axa Newton Promoto+ 2 100/9

Cheapest price: £55 from Amazon. Also available from Startfitness.

Tech specs:

• Weight: 2,360g
• Length of chain: 970mm
• Thickness of chain: 8.5mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: No

This Axa model is a square lock chain with padlocks. Its dimensions make it suitable for thick posts, frames and rear wheels. 

Axa also says that it has a safety level of 15, which is the brand's highest security level.

But does it withstand our rigorous lab tests to earn that high rating? Sign up to Which? to find out.

 Axa Newton UL-230

Cheapest price: £35 from Bikeboom. Alos available from Tradeinn.

Tech Specs:

• Weight: 1,060g
• Internal length x width: 235mm x 110mm
• Diameter of shackle (ex. plastic coating): 14mm
• Type of locking mechanism: Lock and key
• Number of keys: 3
• Bike mount included: Yes

This is marketed as a versatile lock and it should be suitable for a range of standard city bicycles as well as various frames and posts. 

As for security, the manufacturer claims it achieves a rating of eight out of 15.

But what does that really mean? Sign up to Which? to find out more on how we measure security and whether this lock stood strong against our rigorous tests.

 Hiplok Gold High 10mm

Cheapest price: £95 from Hiplok and Biketart.

Tech Specs:

• Weight: 2,406g
• Length of chain: 800mm
• Thickness of chain: 10mm
• Type of locking mechanism: Lock and key
• Number of keys: 3
• Bike mount included: No

This chain lock weighs around 2.4kg, making it one of the heaviest locks we've tested, although it's long so it'll easily fit around your bike frame, rear wheel and whatever you're securing it to.

Does this extra weight provide extra security?

Sign up to Which? to find out if this lock secures your bike against typical tools used by thieves.

 Kryptonite Keeper 785 Integrated Chain 

Cheapest price: £45 from Rutland Cycling. Also available from Bikeinn.

Tech specs:

• Weight: 1,340g
• Length of chain: 870mm
• Thickness of chain: 7mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: No

A thinner chain lock at about 7mm, the Kryptonite Keeper isn’t designed for heavy-duty use which explains why it receives the company’s modest security level of five out of 10. 

But its relatively small dimensions also make it suitable for narrow posts, frames and rear wheels.

Sign up to Which? to find out if this bike lock is for you.

 Kryptonite Keeper Standard 

Cheapest price: £31 from Amazon. Also available from Cyclestore.

Tech Specs:

• Weight: 900g
• Internal length x width: 210mm x 100mm
• Diameter of shackle (ex. plastic coating): 14mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

Weighing 900g, the Kryptonite Keeper Standard is one of the lighter bike locks we've tested. As a result, it may appeal to cyclists who want an easy-to-transport U-lock.

But do its smaller frame and lighter weight come at the expense of security? 

Sign up to Which? to find out how well it stood up against our rigorous tests.

 Kryptonite Kryptolok 685

Cheapest price: £70 from Amazon. Also available from Rutland Cycling.

Tech Specs:

• Weight: 1,078g
• Length of lock (unfolded): 810mm
• Thickness (ex. plastic coating): 5mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

Weighing just over 1kg, the Kryptolok 685 is a pretty light lock for its size – 810mm long when unfolded. 

But does it secure your bike effectively?

Sign up to Which? to find out if this is the bike lock for you.

 Kryptonite New York Fahgettaboudit Kette 1410 

Cheapest price: £160 from Sigma Sports. Also available from Cyclestore and Tredz. 

Tech specs:

• Weight: 4,740g
• Length of chain: 970mm
• Thickness of chain: 14mm
• Type of locking mechanism: Lock and key
• Number of keys: 3
• Bike mount included: No

Kryptonite claims this is a very durable chain lock and gives it 10 out of 10 for security, which is its highest level. It’s also one of the heaviest locks we’ve tested. 

But does it deliver a heavyweight performance to match its billing? 

Sign up to Which? to read our expert review and find out.

 Kryptonite New York Lock Fahgettaboudit Mini 

Cheapest price: £120 at Amazon and also available from Sigma Sports.

Tech Specs:

• Weight: 2,050g
• Internal length x width: 157mm x 82mm
• Diameter of shackle (ex. plastic coating): 18mm
• Type of locking mechanism: Lock and key
• Number of keys: 3
• Bike mount included: No

The Kryptonite New York Fahgettaboudit Mini is a small U-lock, although at just over 2kg it's one of the heaviest bike locks we have tested.

The manufacturer rates its security as 10 out of 10, with a locking cylinder that protects the lock against dirt. But did its security claim hold up when we put the lock through our rigorous lab tests?

Sign up to Which? to find out if this is the bike lock for you.

 Kryptonite New York Lock M18-WL 

Cheapest price: £100 from Amazon. Also available from Sourcebmx.

Tech specs:

• Weight: 2,640g
• Internal length x width: 265mm x 100mm
• Diameter of shackle (ex. plastic coating): 21mm
• Type of locking mechanism: Lock and key
• Number of keys: 3
• Bike mount included: No

A heavy bike lock weighing 2.64kg and claimed to offer maximum security, it should be more than strong enough for locking on to frames and posts securely. 

But is it any good for standard city bicycles? 

Sign up to Which? to find out how it held up against our expert lock-breakers.

 Trelock U4 Mini 

Cheapest Price: £35 from Sports Direct, Evans Cycles, and House of Fraser.

Tech Specs:

• Weight: 741g
• Internal length x width: 147mm x 85mm
• Diameter of shackle (ex. plastic coating): 12mm
• Type of locking mechanism: Lock and key
• Number of keys: 2
• Bike mount included: Yes

Weighing in at just under 750g, the U4 Mini is one of the lightest bike locks we've tested. Combined with its small size and the included bike mounting bracket, this makes it extremely easy to transport.

But does it fulfil its main function of securing your bike effectively?

Sign up to Which? to find out if this is the bike lock for you.

If you're planning on cycling after dark, check our the best bike lights from our tough tests

What's the best type of bike lock?

Security experts recommend using two different types of lock to secure your bike, one of which should be a U-lock, according to the Met Police. 

Different lock types need different tools to break, so using more than one lock type is likely to slow down a thief.

U-locks (or D-locks)

This lock gets its name from its rigid, U-shaped body. U-locks vary in size, strength and weight, but are generally regarded as the most secure type of lock. 

For this security there is sacrifice in flexibility. You need to be able to fit the rigid lock around your bike's frame and wheel plus the object you're securing your bike to, so check before you buy that it's the right size for your bike.

Chain locks

Chain locks are made up of a series of hardened steel links, usually inside a protective sleeve. They can offer similar levels of security as U-locks, but they have pros and cons by comparison. 

They're more flexible than U-locks so are easier to wrap around tight areas of a bike and secure it to a wider range of objects. But they tend to be heavier than similarly secure U-locks and are more likely to rattle if attached to your bike frame while cycling. 

Folding locks

Folding locks consist of several solid steel arms, joined together by steel rivets. They fold up into a compact size, making them easy to transport in a bag or on the bike frame, but open up to a larger area than many locks. This can make them a good choice if you have a large bike or need to secure it to thick objects. 

The multiple hinge points on a folding lock are potential weak spots that can be easier for a thief to break, but our tests aggressively attack the hinge points so you can be sure a high-scoring folding lock still offers great security.

Textile locks

Textile locks are made up of tough composite textiles, usually around a metal core. They offer security along with flexibility at a lower weight.

Some are designed to be worn around the waist like a belt when not in use, making them easy to transport while cycling.

This security and flexibility come at a cost – other types of lock will give a similar level of security for less.

Cable locks 

Made from intertwined metal fibres with a plastic coating, cable locks come in a wide variety of sizes, weights and locking mechanisms. They're flexible and tend to be available in longer lengths than chain locks.

Their flexibility and light weight come at the cost of being the least secure type of bike lock. They may deter an opportunist, but a persistent thief will get through one relatively easily. 

As such you shouldn't rely on a cable lock as your main bike lock, but you could consider one as a secondary lock, as a cheaper extra layer of defence for a wheel, for example.

What features should I look for in a good bike lock?

As we've highlighted, there are many types of bike lock to choose from, with certain locks suiting different cyclists. Secure by Design (the official police security initiative) recommends you lock your bike with at least two locks, one of them being a U-lock.

Deciding on the other type of bike lock to buy generally comes down to your own preferences, but there are some features worth looking out for across all types of bike lock, as they make it harder for skilled thieves to beat it. 

• Hardened steel – a heat treatment that makes steel tougher to break.
• Deadlocks – a type of key lock harder for thieves to force open.
• Pick-resistant locks – these locks have extra mechanisms in the lock barrel, essentially making it much harder for a thief to pick the lock.

Should I buy a key or combination bike lock?

For maximum convenience, combination locks usually trump key locks, as you don't need to remember to bring the key. You will need to remember the code – not necessarily that easy if you don't use your bike that often. 

Combination locks are often regarded as less secure however, because:

1. An observant thief could spot your code as you lock or unlock your bike. To reduce this risk, make sure you shield the code from observers when you enter it. 
2. A combination lock can be 'hacked' without tools. A key lock needs brute force or tools to break it; a combination lock can, in theory, be cracked by trial and error. 

It would take a determined thief less than an hour to work through all the unique combinations on a three-digit lock – far from impossible if your bike is tucked away in a quiet location. We recommend opting for a lock with at least four digits, which increases the number of possible combinations, and the time it would take to try them all, tenfold. 

In practice, a decent combination lock with at least four dials and built-in anti-lock-picking features will offer similar protection to a decent key lock.

An example of an anti-lock-picking feature is 'false gates'. These make it 'feel' to a thief like they have found the right combination, but doesn't allow the lock to open. It will take a thief much longer to beat a false-gated lock.

Can I get away with a cheap bike lock?

Bike locks prices range from around £5 for a basic cable lock to more than £100 for a big-brand U-lock. 

The cheapest bike locks are usually cable locks. These are better than no lock at all, but most thieves will be able to make short work of them. You shouldn't rely on a cheap cable lock as your main lock.

The bike locks we've tested cost from £16 to £120, including a Best Buy for less than £50. While in general the more expensive the lock, the more secure it will be, you don't have to pay a fortune either. 

Is there a bike lock that cannot be broken?

The short answer is no: no lock is unbreakable. 

The aim of bike locks is to make your bike as unappealing as possible, deterring thieves from even trying to nick your bike. You should use two locks to secure your bike, with one being a U-lock.

Our tests have found that the best bike locks, while not unbreakable, will stand up to angle grinders, saws and bolt cutters for several minutes. This will stop an opportunist successfully breaking the lock, and make it more likely a professional will give up or be interrupted when trying to break the lock.

Bike lock security ratings explained 

Manufacturer security ratings

Bike lock manufacturers typically grade the security of their locks on a scale of one to 10. This can be useful when comparing locks in a single brand.

However, different manufacturers use different scales, as well as different criteria to measure their locks' security. This means it's not possible to use manufacturer ratings to directly compare the security of locks across brands.

Our reviews are based on assessments and criteria that are comparable across all locks we test, so you can feel confident the locks that score the highest are genuinely the best. 

If you're interested in a bike lock we haven't yet reviewed, check its security rating by an independent body such as Sold Secure. 

Sold Secure bike lock ratings

Sold Secure is a third-party certification body that rates locks. Many insurance companies recognise its safety ratings, so getting (and using) a lock with this certification may help lower the cost of bike insurance.

There are four Sold Secure ratings; the higher the rating, the more secure the lock. In general, the highest-rated locks are the most expensive.  

• Bronze – the lock offers defence against opportunistic thieves
• Silver – the lock is a good compromise between security and cost
• Gold – the lock offers a high level of security, aimed to secure mid to high-value bikes
• Diamond – the lock offers the highest level of security, aimed at securing high-value bikes and electric bikes

How we test bike locks

We test every bike lock based on criteria stipulated in the British Standard, which is BS EN 15496:2008 Cycles and follow the requirements and test methods for cycle locks. 

What this means in practice is that we throw everything including the kitchen sink into testing a lock's security, as well as assessing how easy to use and how durable it is.

Overall strength

We test each lock's resistance to being cut, pulled apart and hit by machines under strict lab conditions. This ensures that each lock's strength has been tested in the exact same way, giving an objective measure of how tough each lock is. 

• Cutting test – can the lock be cut by a force of 55kN? That's about two and a half times the force a standard bolt cutter can apply.
• Tensile test – can the lock be pulled open by a force of 10kN? That's about the equivalent of two adults hanging from the lock.
• Impact test – can the lock be broken by a 3kg impact device? We drop the impact device on the lock five times in 90 seconds.

Locks that pass all these tests are really tough, meaning they will stop an opportunist and slow down a professional thief – to the point where they are likely to be interrupted or give up trying to beat the lock. 

Security against hand tools

We then test each bike lock in a real-world situation. A bike is secured with the bike lock and we give an expert lock breaker three minutes to beat the lock using selection of tools a professional thief might have access to.

The specific tools we use are targeted around each type of lock, but include bolt cutters, nippers, saws and lock picks – even a battery powered angle grinder, our toughest tool.

If our experts can't break the lock in this time, or if the locks last at least a couple of minutes against the angle grinder, you can feel pretty confident the lock will protect your bike from thieves. 

Ease of use

We assess the lock for how easy it is to use and transport, including:

• Can the lock be mounted to the bike?
• How smooth is the locking/closing function of the bike lock?
• How much does it weigh?
• How noisy is the bike lock when cycling?
• How durable is the lock? - we spray each lock with salt solution to replicate several years of weather exposure

How is the Which? score calculated

Each test we perform factors into the final score for each bike lock. To be a Best Buy a lock needs to score at least 80%, meaning it provides a great level of security against lots of different attacks, while still being easy to use. The overall score is:

• Overall strength (40%)
• Ease of use (35%)
• Security against hand tools (25%).