Best bike locks: heavy duty and portable locks for keeping your bike safe

Best bike locks

A bike lock might not be the most exciting item to splash out on, but sadly theft is not uncommon and a good quality lock is an effective deterrent.

We’ve tested a wide variety of bike locks, ranging from ultimate security heavy-duty U-locks, to portable lightweight options offering a little more peace of mind at the café stop—with many others in between.

Just like buying a bike, there’s a number of considerations it’s worth reflecting on before you commit to a purchase. For instance, where are you planning on locking up your bike and for how long? What’s the worth of your bike? Does your insurance specify a particular lock security rating? How is a lock’s security determined? Do you even have insurance?

For answers to these questions and much else besides, you can click the links below to skip directly to the bottom of the page and get all that juicy information. If you know what you’re looking for and want to get straight on to our favourite locks, well, that’s just below.

Our pick of the best bike locks

We’ve put the locks in order of security, starting with the most secure. For locks with the same security rating, we’ve ordered by price, starting with the most expensive.

With each product is a ‘Buy Now’ or 'Best Deal' link. If you click on this then we may receive a small amount of money from the retailer when you purchase the item. This doesn’t affect the amount you pay.

best bike lock

Milenco Dundrod ++

Security rating: Diamond
Weight: 2,458g
Lockable area: 15cm x 22.5cm | 338cm²
Reasons to buy
+Very secure+Good size+Three keys supplied+Lock barrel dustcove
Reasons to avoid
-Not designed with portability in mind

Manufactured by Milton Keynes based security brand, Milenco, the Dundrod ++ surpasses the requirements for Gold and is one of the few locks that meet Sold Secure’s Diamond standard.

Although most bike insurers will only require a Gold rated lock for cycles worth over £1,000, if your bike has a sentimental value or is a model that can’t be replaced, you’ll be wanting something more secure—which is where a Diamond rated lock comes in.

The Dundrod ++ is reassuringly plump with a shackle and crossbar that are visibly beefier than a standard U-lock. The lockable area is on the larger side for this style of lock, making it quite easy to secure the bike through the frame and wheel.

Bear in mind that if you are considering a lock of this application, it is worth using two to lock each wheel to the frame and immovable object, as well as potentially upgrading the locks to wherever you are keeping your bike.

Coming without a bike mount and weighing just under two and a half kilos, the Dundrod ++ isn’t intended as a lock for use when out and about—although this certainly isn’t ruled out, providing you have somewhere to put it.

best bike lock

Abus Bordo Granit X Plus 6500

Security rating: Gold
Weight: 1,962g
Lockable area: 14cm x 31cm | 434cm²
Reasons to buy
+Very secure+Large lockable area+Bike mount included
Reasons to avoid
-Heavy-Only two keys included-Expensive

A folding lock brings a range of benefits over the venerable U-lock design. Not only do they tend to pack down smaller and have a larger lockable area, but their flexible nature greatly increases the range of objects you can lock your bike up to.

The typical downside of a folding lock is that with so many moving parts, they tend to be less secure than a simpler design, such as a U-lock.

As such, the Abus is one of the only Gold rated folding locks currently available, but with this superlative security does come with a couple of trade-offs. Costing £144.99 and tipping the scales at just under two kilos, compared to the Gold rated Zéfal K-Traz U17, the Abus lock is over four times as expensive and weighs just over half as much again.

The Bordo Granit X Plus certainly isn’t all things to all people—but then, it isn’t trying to be. As a high security folding lock, it performs excellently. In addition to all the general benefits of folding locks, the Abus has a comprehensive rubber coating to protect your paintwork, a bike mount that is simple to set up and in day-to-day use, as well as an integrated weather seal on the lock barrel—adding some very welcome weather protection.

best bike lock

Oxford Alarm-D Pro

Security rating: Gold
Weight: 1,419g
Lockable area: 10.1cm x 20cm | 202cm²
Reasons to buy
+Well executed alarm feature+Reasonable price+Reasonable weight+User friendly shackle
Reasons to avoid
-Rubber cover doesn’t extend all the way across the crossbar

As the name would suggest, this Oxford lock comes with an inbuilt alarm that will sound if the internal motion sensors detect any tampering. It’s very simple to use, with arming and disarming controlled by just a turn of the key in the lock.

The calibration of the motion sensor was pretty spot on, detecting any suspicious fumbling, but not going off when the bike is just knocked a little when locking another up next to it. With the battery easy to access (when the lock is open), you can quite easily disable the alarm completely if you need it to work simply as a lock for any reason.

But this lock is by no means a novelty, it performs the basics really well. The bent shackle makes it easy to attach the crossbar, three keys are provided with more orderable, the bike mount is easy to set and works well in day-to-day use, plus its weight is pretty middle of the road for this style of lock.

The only reservation I have about this lock is that the rubber bumpers on the crossbar don’t extend all the way across, so some care is needed not to scratch your bike on the middle section of exposed metal.

best bike lock

Zéfal K-Traz U17

Security rating: Gold
Weight: 1,278g
Lockable area: 11.5cm x 23cm | 268cm²
Reasons to buy
+Great value+Sold Secure Gold rating+Significantly lighter than expected
Reasons to avoid
-Plasticky bike mount-Straight shackle

A brilliant low-cost option, making Gold Sold Secure even more accessible to everyone. At this price, it wouldn’t even be too much of an outlay to buy one for every bike in your household. Although it might be tempting to use one lock to secure multiple bikes, especially if you have a longer chain link lock, that only serves to tempt thieves. Far safer to have locks for each one.

At just under 1.3kg, the K-Traz U17 is surprisingly lightweight—especially considering its price and security rating. A complete plastic coating minimizes the risk of paintwork coming into contact with metal.

The two downsides are the straight shackle, which does make it more difficult to mount the crossbar than a bent design, and the plasticky bike mount. This is a little fiddly to set up, using two long screws to clamp the bracket to the frame, and the release mechanism for extracting the lock feels a little flimsy which makes it a bit of a struggle to dismount the lock.

For the money, the K-Traz U17 is a brilliant lock, but if you’re after quality all-round performance, you will need to set your price bracket a little higher.

best bike lock

Kryptonite Messenger Mini With U-Lock Extender

Security rating: Silver
Weight: 1,109g
Lockable area: 9.5cm x 16.5cm (main lock); 8.3cm x 9.5cm (extra shackle) | 236cm²
Reasons to buy
+Lightweight+Extra shackle is genuinely useful+Relatively secure+Sliding dustcover
Reasons to avoid
-Doesn’t come with a bike mount-Only comes with two keys

Usually, the consequence of a lightweight and compact U-lock is a bit of a sacrifice in its usability, being too small to loop around objects or actually reach your bike.

But that simply isn’t the case with this lock. By the addition of a secondary shackle, the weight and size is kept low, but the total lockable area remains very respectable. Securing a wheel to the frame—in addition to reaching an immovable object—simply doesn’t present a struggle.

The main shackle even has a bent foot, making it quite an easy to mount the crossbar—exactly what you’d want in a lock designed around portability.

Regarding that portability, though, is a significant omission. The lock doesn’t come provided with a bike mount and the mount available that is compatible with this lock is quite a cumbersome looking handlebar mounting option. For a lock that’s supposed to be used on the go, needing to bring some kind of bag to stow it in is quite an inconvenience.

It is also a little on the expensive side for its combination of security rating, weight, lockable area and portability. That said, if you do always have somewhere to keep the lock on your trips about town, you won’t be disappointed in its application.

best bike locks

Hiplok Z Lok Combo bike lock

Security rating: Unrated
Weight: 70g
Lockable area: 6.8cm (diameter)| 147cm²
Reasons to buy
+Lightweight and portable+Combo lock gives a bit of extra security over the standard Z Lok+Cheap+Long enough to take in the down tube and rear wheel+Easy to operate+No keys to lose
Reasons to avoid
-Will not stop a concerted attack with tools for long

The Z Lok weighs only 70g, so you’re not going to feel burdened by it if you stuff it into your pocket or clip it round your frame. The design is like an oversize zip tie and inside the plastic covering is a steel ribbon.

If you use the Z Lok to secure your frame to a post or railing, it’s enough to stop a thief from walking away with your bike, although it’s unlikely to stand up long to a bolt cutter. Its steel band design is significantly more robust than other lightweight locking options, which tend to use thin cables, though.

At 40cm long, there’s enough length to secure your frame to something immovable and possibly your rear wheel too. Because of its zip tie-like design, you can also shorten the loop to make it harder to get leverage with a cutter. There’s a release lever to undo the ratchet when unlocked.

It’s a clever, useful bit of kit to carry around for the coffee stop or quick errands on the bike and cheaper than a full-strength lock too.

Types of bike lock

Types of bike lock

There are many different styles of bike lock, each with designed with a particular use case in mind.

D- / U-locks with their simple and robust design lend themselves to high security applications, although with a consequential high weight. But the same elements which make U-locks and easier design to make high security, also means that mid-level security can be offered at a sometimes surprisingly low weight. This versatility is why the U-lock design is so popular for bike locks.

Folding locks bring a different set of benefits. Not only does their design allow folding locks to pack down smaller for easier transportation, but they also tend to come with a larger lockable area and their flexible nature greatly increases the range of objects you can lock your bike up to. The typical downside of a folding lock is that with so many moving parts, they tend to be less secure than a simpler design.

Abus Bordo Granit X Plus 6500

Chains go some way to merge the benefits of folding locks and U-locks, tending to have a similar security level to U-locks but being flexible like a folding lock. The downsides mainly centre around the weight, which is often considerable (over 3kg) and therefore limits them to use only at home.

For securing multiple bikes, using a couple of U-locks is much safer than a single chain – and with Gold rated options such as the Zéfal K-Traz U17, the total price and weight will probably even be similar.

Lightweight locks tend to use a cable design. These are pretty vulnerable to cutting attacks, but are effective against opportunistic thieves without specialist tools. These are good for providing a bit of extra security at a café stop, so someone can’t just sneak off with your bike while you’re looking in the wrong direction.

However, they aren’t robust enough to use in high crime areas when you are leaving your bike for any length of time, and your insurance probably won’t cover you if your bike is stolen while locked up with one.

How bike locks are tested

How testing is done

SingerGM / Getty Images
(Image credit: SingerGM / Getty Images)

Sold Secure is an independent lock testing company and its ratings are the industry standard for the security of bike locks. At the purpose-built laboratories in Rugby, locks are put through their paces against a variety of different attacks including—but not limited to—drilling, sawing, wedging and lock picking.

Depending on how a lock performs in these tests, it is awarded a rating of Bronze, Silver, Gold, and more recently, Diamond. As a broad rule of thumb, Bronze is only deemed as effective against opportunistic theft, Silver is good for bikes up to £1,000 and Gold is for bikes more valuable that £1,000 and for particularly high crime areas.

With the security ratings so comprehensively covered by Sold Secure, our test here focuses on the liveability and user friendliness of the locks. How they perform in day-to-day usage and assessing the value for the functions they provide.

The importance of cycle insurance

The importance of cycle insurance

Westend61 / Getty Images
(Image credit: Westend61 / Getty Images)

Unfortunately, perfectly secure bike locks simply don’t exist. With the right tools, knowhow and inclination, a determined thief will be able to get through any lock.

As such, it is important to make sure that you have appropriate insurance, so that if your bike is stolen, you are at least covered.

Many home insurance policies will only cover bikes up to £1,000, so if your bike is worth more than that, you really should take out some specific bike insurance. These policies also tend to include other benefits such as public liability and personal accident cover, so are well worth the investment.

Different insurers will have different requirements, so make sure to check the policy wording of your own insurance, but typically, if a bike is worth over £1,000 it will need to be locked using a Sold Secure Gold rated lock. If the bike is worth under £1,000, it will need to be locked with a Silver rated lock. Few insurers will cover a bike locked with a bronze or unrated lock.

How to lock your bike up securely

Typical insurer requirements

How to lock your bike up securely
(Image credit:

Not only will your insurer require you to use a certain level of lock, but you’ll also have to lock your bike in a particular fashion in order to be covered.

This isn’t to try and catch you out, it’s just there’s a very different level of risk depending on the way in which you’ve locked your bike up. We’ve all seen lonely front wheels securely locked to railings with the quick release undone and the rest of the bike long gone.

You’ll need to lock your bike through the frame – and preferably the rear wheel – to an immovable object. An additional cable may need to be used to secure the front wheel as well. This generally applies both at home and when locking the bike away from home.

Ultimate security

How to lock your bike up securely

(Image credit: Webstockreview)

Sometimes the worth of a bike is measured in more than money – if your bike has a sentimental value or is a model that can’t be replaced, an insurance payout is not going to cover what was lost. In this case, prevention is much, much better than any ‘cure’.

For the ultimately secure set up, you should use two Diamond rated locks and use them to lock each wheel to the frame and through to an immovable object. When locking each wheel, make sure to go around the rim rather than just through the spokes – these can be cut and replaced very easily.

You’ll want to be sure that the object you’re locking to is genuinely immovable, being at least equally as secure as the locks. Depending on your garage setup, you may need to purchase a ground anchor to ensure this is the case.

Also, don’t overlook the security of the place you are locking your bikes, you may need to upgrade the locks to your garage, for example. But equally, don’t go overboard. Five set of locks on a door and three security cameras are only going to intrigue a thief. Discrete but high security is the best combination.

This is well in excess of what any insurer would ask you to do. If you would be satisfied with an insurance payout should your bike be stolen (provided it was locked to the insurers’ standards), then this level of security is completely unnecessary. But if your bike is genuinely irreplaceable, these are the step to take.

Low security


For a cheap and simple, paired down town bike, you could get away with using a small Silver rated lock and some lockable quick release skewers to keep the wheels safe. This is a lighter and simpler solution than the lock and cable method preferred by insurers, but as a consequence, you may not be covered locking your bike up in this way.

Either double check with your insurer that they will cover you locking your bike in this way, or make sure your bike is cheap enough that if it does get stolen an insurance claim wouldn’t be worth it anyway.