The best bike locks: D-locks, foldable locks and chain locks tested

24 different models cropped, cut, and hammered to sort the wheat from the chaff

The first thing to realise is that no single lock is unbreakable. Armed with the right tools and knowledge, a person who really wants to steal your bike will, no matter what you lock it up with.

What you can do is deter the bike thief looking for an easy steal, or give the more determined a much harder time.

With that in mind, one of the best bits of advice we can give you, after many years of busting and picking locks in our tests, is to use two locks of different types and brands.

If a thief is adept at picking a certain type of lock, and has the tools to do so, it’s unlikely that they will also have the tools or the knowledge to pick a completely different type. Two budget locks that are wildly different in style and key/lock-cylinder types are sometimes better than just one expensive lock.

Lock lingo

  • Key: There are various types of keys, but all work a lock mechanism by moving pins or discs into alignment to allow the lock plug to be turned and open the lock
  • Shackle: We know the shackle as the D-shaped part of a D-lock/U-lock or padlock. It shackles two things together. In our case, it’s our bikes to something sturdy
  • Links: Chains are made up of links; hoops joined together. The smaller the internal diameter of the links the better, as this gives less space for a lever to be inserted
  • Protection: Nobody wants a bare metal lock clattering against their frame. A cloth cover is handy to keep your pride and joy looking nice and to prevent the lock from corroding
  • Lock barrel: Manufacturers will centre the lock mechanism in the centre of the barrel. Check the weight of the barrel because if it’s heavy that’s a sure sign it’s armoured
  • Multiple keys: Multiple keys are essential, with manufacturers such as OnGuard offering up to five with a lock. Keep one at home, one at work and one on your keyring
  • Maintenance: Check the action of the mechanism because locks spend most of their lives outdoors, so corrosion can be a problem. Use a light lube or water repellent (GT-85 or WD-40) liberally
  • Warranty: An extended warranty is always good. It’s not going to cover you against theft but it should be a sign that the lock won’t fall apart or seize up on you
  • Anti-theft guarantee: This guarantee is a form of insurance pioneered by Kryptonite. It does bump up the price, but definitely adds peace of mind into the package

How we tested...

£11,000 worth of locks tested to destruction

Over the two decades that we’ve been putting together our intensive lock tests we’ve always used a combination of manual and power tools, and force and finesse to try and break locks. This time we’ve upped our game, significantly, by using the facilities of Germany’s biggest security manufacturer, and more importantly its state-of-the-art test labs, and training on how to use the machines on offer.

We devised a full-on torture chamber of tests that fully simulate each and every way a lock is attacked and broken. For this we needed multiple models from each manufacturer, so thank you to those who took up the challenge and supplied test samples willingly.

With nine tests on a total of 29 different models (24 are shown here with seven reviews below), that’s 261 separate tests, and a total of in excess of £11,000 worth of locks tested to destruction...

  • Bracket test: Some of the locks come with a handy bracket to fit to your commuter bike. We tested the brackets fixed to a bike that’s fixed on a treadmill, with bumps and lumps to simulate road conditions. This ‘rattle’ test runs for a total of 200 hours, which is plenty of time to see if the bracket is up to the job of carrying your lock safely
  • Corrosion test: One of each lock was subjected to 168 hours in a climate chamber to ISO 9227 standards. The time is equivalent to around 10–12 months of outdoor use in a salty air environment, such as living on the coast. Over the 168 hours temperature and humidity both fluctuate to further simulate real-world conditions
  • Freeze and hammer test: This test simulates the use of plumber’s freeze spray, which chills the metal. The theory is that it’ll make metal more brittle when struck with a hammer. Our test lab consists of a chiller cabinet that freezes the lock down to -40°C, it’s then struck with a weight simulating a full force sledgehammer blow multiple times from 1m and from 2m

Locks were subjected to a standard saw blade and a tungsten item
Locks were subjected to a standard saw blade and a tungsten item

  • Saw test: Our test machine is an articulated saw. Each lock was cut first with a fresh, standard steel blade. If it survived that test, it was then cut with a high-quality, precision tungsten blade in the same saw
  • Bolt crop test: The bolt cropper is perhaps the favourite tool of the modern bike thief. Short, concealable bolt croppers are available for very little cash and can get through most budget locks with little fuss. Higher standard locks are much tougher, and those that cross over into motorcycle security stronger still. Our bolt cropping rig has to be capable of out-performing hand-operated bolt croppers, so the one we’ve used is a hydraulic jaw that cuts like a bolt cropper, but is capable of applying in excess of 250 kiloNewtons of pressure, that’s around the equivalent of a 1.5m-long set of bolt croppers operated by a couple of contestants from World’s Strongest Man

Our corrosion test replicated a year-long hard life outdoors
Our corrosion test replicated a year-long hard life outdoors

  • Tensile pull test: This pulling rig had to simulate the bottle jack approach to breaking locks. A small hydraulic bottle uses a jack to push apart the two sections of lock, breaking the mechanism and causing the lock to fail. Our hydraulic test rig does the same by pulling on both parts simultaneously. This rig is capable of over seven tonnes of pulling power, your average bottle jack can perform to around three
  • Torsion test: The good-old torsion attack, or crowbar to you and me, is a very effective method but the downside is that it usually leaves the bike being stolen with significant damage. Our test rig can torsionally twist a lock to massive pressures, the equivalent of using a crowbar of more than 1.5m and one of those world’s strongest men doing the crowing!
  • Picking test: Picking locks is a learnable art, and with many ‘picks’ available online we are seeing a rise in bikes being stolen this way. We used a resident expert armed with an inexpensive homemade pick to try and open the locks on test

We’ve got the full lowdown on lock performance after compromising 29 popular locks
We’ve got the full lowdown on lock performance after compromising 29 popular locks

  • Grinder test: Hand-held powerful battery-operated angle grinders are a fast and effective way to cut through metal. However, they do generate a lot of noise and sparks, so if you park your bike in a high traffic area, and not hidden out of sight, you’re less likely to see this method of attack being used in broad daylight. For our test we used an off-the-shelf unit, with multiple batteries and a constant cycle of recharging, along with a fresh grinding disc for each test, so that each lock had the exact same conditions to record the time it took to cut through
  • The results: The resulting data from this massive test was collated and assigned a score for each test, but note that not all the tests are applicable to every lock design. The different designs were rated with an overall score, and you can read full reviews of the best seven below. We’ve included a table with the full test data too which you can see by clicking on this link

D-locks or U-locks

The D-lock, or U-lock as it is alternatively known, is the classic bike lock. The design consists of a big shackle and toughened crossbar with the lock mechanism built in. It’s been around for years, and it’s really just a supersized padlock. The benefits are the strength for its size and relative portability.

The downsides are the slightly awkward shape for locking more of your bike into it. You’ll want to add in an accessory cable or second lock to cover everything.

Abus Granit Extreme 59

BikeRadar score4.5/5

Abus Granit Extreme 59
Abus Granit Extreme 59

  • Price: £230 / $279.99
  • Weight: 2,700g
  • Shackle diameter: 16mm (square)
  • Size: 260mm
  • Rating: Thatcham

The Extreme 59 is like taking an X-Plus and putting it on a high-protein diet, this is the toughest D-lock you’ll find. With a torsional resistance that’s 1,000Nm higher than its nearest rival, and tensile resistance that would handle a couple of vans pulling on each end, it’s impressive.

Weather resistance is impeccable as is its resilience against picking. Under bolt cropping it’s in the top three of all the locks tested. If you prize your bike and have somewhere to store your lock when not using it or want something tough for home use then the Extreme is perfect.

The high price holds it back from a full five-star review.

ABUS Granit X–Plus 540

BikeRadar score4/5

A clever, quality D-lock that’s great if you need to carry a lock with you
A clever, quality D-lock that’s great if you need to carry a lock with you

  • Price: £95
  • Weight: 1,460g
  • Shackle diameter: 13mm (square)
  • Size: 230mm
  • Rating: Sold Secure Gold

The X-Plus 540 is one of the cleverest D-lock designs ever, with its patented square profile shackle that resists torsional attacks better than most, taking a massive 1,750Nm of pressure.

The state-of-the-art lock mechanism beat our lock picker, and has great resistance to bolt cropping (146kN) that far outweighs its relatively light weight.

The quality of the materials and the build meant this one outlasted our corrosion test and the EasyZyKF bracket took the full 200 hours of abuse. In cutting tests it stripped the standard saw blade, and took over 2 minutes of cutting with tungsten. The power grinder result of nearly four minutes was only beaten by heftier rivals.

  • Verdict: The state-of-the-art lock mechanism beat our lock picker

Kryptonite New York M18

BikeRadar score4/5

Kryptonite New York M18
Kryptonite New York M18

  • Price: £100
  • Weight: 2,640g
  • Shackle diameter: 18mm (round)
  • Size: 260mm
  • Rating: Thatcham

The New York M18 is a beast of a lock, at over 2.5kg and with a massive 18mm diameter shackle it’s built of sturdy stuff. The double deadbolt mechanism is centred inside the ovalised crossbar using a pick-resistant disc cylinder mechanism.

The New York scores with its resistance to bolt cropping, sawing (best on test), tensile (best on test), and torsional resistance (runner up). With only its middling performance against the angle grinder going against it, the New York is a tough D-lock built the classic Kryptonite way.

It may not be as clever as an Abus in its design but the results are much the same.

Hiplok DX

BikeRadar score3.5/5

Hiplok DX
Hiplok DX

Compact, tough, and well priced for a top performing lock

  • Price: £70 / €80
  • Weight: 1,120g
  • Shackle diameter: 14mm (round)
  • Size: 150mm
  • Rating: Sold Secure Gold

Hiplok’s DX combines a compact D-lock with a casing that protects your bike with soft touch materials and makes carrying easy thanks to the two built-in prongs that are designed to slip into your jeans pocket, or behind a belt.

These ergonomic touches add a little extra to what is a solid performing little lock. It’s built to last with excellent weather protection, and it’s a tough cookie when it comes to sawing, twisting and grinding.

Only a lowly performance on the tensile (pull) test gave any cause for concern, but being able to withstand 28kN is more than enough to see off most compact, portable bottle jacks easily.

The relatively shallow shackle is bolstered by a big 85mm width, so even with its compact size we were still able to safely get it through the frame and back wheel of our bike. You will definitely need a second lock or some accessory cables to properly secure all the extremities of your ride though.

  • Verdict: The DX is a tough cookie when it comes to sawing, twisting and grinding

Foldable Locks

Sometimes you need a lock that’s more portable than a D-lock or chain but one that’s stronger than a simple cafe stop cable lock.

If you want a mix of light weight and transportability with toughness that you can trust for shopping stops and long lunches these might be for you.

Litelok Gold

BikeRadar score3.5/5

Unique design that’s proved a tough, convenient option
Unique design that’s proved a tough, convenient option

  • Price: £85
  • Weight: 1,120g
  • Shackle size: 265mm (circular diameter)
  • Size: 736×50mm
  • Rating: Sold Secure Gold

The Litelok Gold’s unique design combines a heavyweight disc lock mechanism with a mushroom stud and socket connection set within a sturdy steel casing joined by a nylon mesh clad series of steel cables.

The design keeps weight down and provides plenty of flexibility. Carrying the lock is easy, either leave it straight and strap to your top-tube or lock it into its circle shape and strap between the seat and top tube.

The flexible nature makes it adaptable to what you lock it to, though it can be a little stiff so hold the pressure while pushing the two locking ends together.

It performed perfectly after weather testing, and chilling and hammering only left a dent in the lock case. A standard blade sawed through the cables in 52 seconds and just 15 with a tungsten blade.

The Litelok took a massive amount of abuse (222.5kN) from the bolt cropper. Torsion tests had little effect, and in the tensile test it proved itself too. It didn’t last long against the angle grinder though.

  • Verdict: The design keeps weight down and provides plenty of flexibility

Abus Granit X-Plus Bordo

BikeRadar score3.5/5

Abus Granit X-Plus Bordo
Abus Granit X-Plus Bordo

  • Price: £110
  • Weight: 1,520g
  • Shackle diameter: 5.5mm thick plates
  • Size: 6×150mm plates
  • Rating: Sold Secure Gold

The much-imitated Bordo design uses 150mm hardened steel plates linked together by domed hardened rivets for a strong lock that can fold into a compact 190×70×40mm package.

It sailed through corrosion testing and the lock mechanism, being an X-Plus unit, couldn’t be picked. You can’t pull the barrel either as it’s set within a hardened steel case with folded over ends.

Under saw attack it’s unfazed by a standard blade, though a tungsten blade got though in under a minute. Bolt crop resistance was impressive for such small steel sections and it out performs plenty of D-locks here. A grinder will make pretty short work of the plates however.

Chains

A chain by its very nature is adaptable; you can swing it around pretty much any shape and thread it through your bike. Its shape also makes it difficult to attack with traditional tools; try crowbarring a chain.

Chains make sense for your place of work or home as they are usually quite hefty and ungainly to carry safely.

Hiplok Homie Gold

BikeRadar score3.5/5

Heavy but great for securing multiple bikes at home
Heavy but great for securing multiple bikes at home

  • Price: £110 / $159
  • Weight: 4,200g
  • Link size: 10mm round links
  • Size: 150cm
  • Rating: Sold Secure Gold

The Homie at 1.5m long is designed to thread through multiple bikes, and as the name suggests is for home use.

The individual links are made from hardened steel, as is the shackle to protect the cylinder lock. When using the Homie be careful not to drop it onto a frame tube as that 4.2kg of weight will cause some damage.

The Homie is well protected against corrosion and hammer tests didn’t affect it either. Bolt cropping on the links was middling, but on the lock shackle much more impressive.

The lock cylinder is good against pick attacks and the links are some of the toughest on test. It’s a strong solution and one we’d recommend for home use only. For the money you are getting a lot of lock and one that’ll work on multiple bikes at the same time — thread it through a floor or wall anchor and secure two or three bikes.

Be careful how you handle it and don’t drop it on your favourite lightweight carbon frame.

  • Verdict: For the money you are getting a lot of lock and one that’ll work on multiple bikes

Full verdict

The Abus Granit Extreme is our overall best in test
The Abus Granit Extreme is our overall best in test

For a full scored chart on how each of the 24 locks performed in this complete test then click on this link.

For home use a chain is a great option and the HipLok Homie offers multi-bike protection and is tough, so takes honours for best chain.

If you want something to take with you on rides for short stay locking, we’d recommend the Abus X-Plus Bordo and the unique LiteLok Gold, which gains the best folding lock award.

D-Locks are still the leading design, and if you’re looking for one to carry with you then Abus’s Granit X-Plus is excellent. If you’re on a tight budget then Kryptonite’s Keeper hybrid chain/folding lock offers plenty of bangs for your buck, it didn't make it into this list but was easily the best budget lock on test.

Our overall best in test award goes to the mighty Abus Granit Extreme. This hugely tough D-lock is simply one of the best designs around, with its twist-resistant square profile shackle, tensile-resisting parabolic shape of the shackle and the tank armour-tough steel plate wrapping the pick-resistant X-Plus lock barrel.

This article was originally published in Cycling Plus magazine, available on Apple Newsstand and Zinio.

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