Group test: Grinder-resistant locks

One of the biggest issues with using a bike for transport is the risk of having it stolen if you leave it anywhere. The risk of theft has increased in recent years due to the use of cordless angle grinders.

These can be hidden under a jacket or in a bag, and they’ll cut through most D-locks, chains or bar locks in a matter of seconds. Lock manufacturers are fighting back with specifically grinder-resistant designs, using a whole new level of material technologies.

I took an angle grinder to six of the best options from Abus, Hiplok, Kryptonite, Litelok and OnGuard to see which held out the best. Then I considered their other pros and cons in terms of security and everyday use to find the best deterrent.

Note that these locks are grinder resistant, not grinder impervious. Any lock will fail, given time and enough cutting discs. I set a time limit of five minutes for attacking each lock.

You’d hope someone might raise the alarm after that or that the thief would give up and choose an easier target. I used as many cutting discs as each five-minute attempt required.

You’ll see that there are two Liteloks in this test. I’d hoped to include a Masterlock but it didn’t arrive in time. I also contacted Squire and Oxford Products for a lock but their new designs won’t be available until spring.

Litelok X1

Price: £149.99
Weight: 1,734g
Shackle size: 197×101mm
Overall cut time: 158 secs to get through one side
Available from: Litelok

The British-made Litelok X1 is the cheapest and lightest of the locks here. The slim shackle and shallow cladding mean it has still has reasonable shackle space to cope with large-diameter frame tubes or locking options. It’s rated Diamond by Sold Secure for both cycles and motorbikes.

The paint-friendly, soft rubber coating has reflective details and the silicone key cover is very weatherproof. You get two keys and a neoprene pouch included, with the Tactical or Twist-and-Go frame mounts available as extras. Litelok also runs various bundle deals, as well as bulk offers if you’re buying for a club, workplace or family.

In testing, I was able to cut through the Barronium composite armour shackle in two minutes and 38 seconds, with a couple of readjustments. The disc was toast, however, and the anti-twist design means you’d need to swap to a fresh one to cut through the other side before being able to take the bike.

Verdict: Light, affordable UK-made lock that offers reasonable resistance against grinders

OnGuard Rocksolid 8950

Price: £199.99
Weight: 1,428g
Shackle size: 176×82mm
Overall cut time: 66 secs + 1 disc to get through one side
Available from: OnGuard

The OnGuard Rocksolid is the lightest lock in the test by over 200g but it’s also the narrowest and one of the shortest. So if there are big tubes on your bike or locking spot, it might be a struggle to fit both in. A ‘proprietary blend of ultra high-strength materials and multi-layered defence system’ gains it a Sold Secure Diamond rating.

The thick rubber cover on the shackle and body protect paintwork, and also display the highly textured face of the steel inner core. You don’t get a bracket included but you do get no fewer than five keys, which is great for family or workplace use.

The textured finish uses a similar coating to most cutting discs, and I’ve seen some tests where the disc wears down without even damaging the lock. In my test, I had to change the disc after 40 seconds, which would add at least 30 seconds to the attack.

It was another 26 seconds before I was completely through but, again, the anti-twist design means you’d need to get through both sides for a full release.

Verdict: Very light, paint-friendly lock but security seemingly depends on the disc used

Hiplok D1000

Price: £249.99
Weight: 1,917g
Shackle size: 155×92mm
Overall cut time: 110 seconds + 3 discs to get halfway through one side
Available from: Hiplok

Hiplok was the first brand to bring out a specific anti-grinder lock, and it was the cheapest lock that I gave up trying to get through. While the D1000 is the shortest lock here, Hiplok also makes a D1000X, which has a longer shackle.

A significant amount of space is taken up by the super-thick rubber, which makes it very paint friendly, and there’s a thick rubber tongue over the lock mechanism. It’s Diamond rated and you get a 10−year ‘lifetime’ warranty and three keys. Brackets are extra. Note that Cycling UK members get 20% off Hiplok products.

Hiplok uses a ‘specialist composite material technology’ for the shackle, which toasted three discs in 30, 50 and 30 seconds respectively. The thick rubber meant the latter two shredded as well, which certainly scared me – and would likely do the same to a thief.

Even after a combined cut time of almost two minutes I was only halfway through when I cut the rubber away to check. So you’re looking at over five minutes with disc swaps to even think of breaching one side.

Verdict: Relatively light lock in two shackle-size options. It toasts discs fast enough to defeat most grinder attacks

Litelok X3

Price: £249.99
Weight: 2,222g
Shackle size: 195×99mm
Overall cut time: 300 secs to get 25% through one side
Available from: Litelok

Litelok says the X3 is four times more grinder resistant than the cheaper X1. The internal space is only fractionally smaller than the skinnier X1 but the Abloy Sentry locking mechanism and chunkier build makes it almost 500g heavier.

It’s still fairly light for the level of protection, which includes a Diamond Sold Secure rating for bike and motorbike.

The rubber coating makes it bike-frame friendly, and while the reflective detailing is ‘stealth’ it’s quite obvious at night. A neoprene pouch and two keys are supplied. Frame mounts are available as extras, as per the X1.

Litelok says the Barronium composite construction uses a ‘hardened fine-grain, high-tensile steel core’. While I made some initial progress, it soon slowed to effectively nothing. A lot of heat was generated as the rubber coating melted and sparks flew from the glowing metal. Yet after five minutes I was only a quarter of the way through.

Verdict: Don’t let the skinny looks deceive you: this lock is a seriously tough thief-beater

Kryptonite New York Lock Diamond Standard

Price: £269.99
Weight: 2,418g
Shackle size: 204×95mm
Overall cut time: 300 secs +3 discs to get 10% through one side
Available from: Kryptonite

This beefy lock lives up to its name as Kryptonite for bike thieves. A thick body and generously sized shackle make it the heaviest on test, and it’s the only one to come with anti-theft insurance (£3,000 in the UK).

It’s Diamond rated, there’s a five-year warranty, you get three keys, and the lock mechanism is hidden behind a little sliding door to keep it clean.

Rubber coating protects your bike, and a frame mount is included. Despite an enthusiastic shower of sparks as the disc cut through the outer steel layer, it was soon obvious that the grinder had met its match.

The discs couldn’t get through the secondary ‘diamond layer’ over the steel core. The first evaporated to the point where the grinder knuckled out in 22 seconds. The second was dust in 36 seconds without getting noticeably further. Another disc, another 30 seconds, and I was still less than a millimetre deeper.

Verdict: Comically casual grinder denial makes this Kryptonite lock the test’s security superhero

Abus Granit Super Extreme 2500

Price: £270
Weight: 2,187g
Shackle size: 223×105mm
Overall cut time: 300 secs + 2 discs to get 25% through one side
Available from: Abus

The Abus Granit is the biggest lock on test in terms of inner dimensions, depth of cladding and the 31×28mm thickness of the carbide steel core. It comes with a substantial multi-position bike mount as standard.

‘XPlus’ and ‘Power Cell’ locking tech ensure a Diamond Sold Secure rating. You get two keys as standard, and as well as the usual fast replacement scheme, Abus also offers ‘keyed alike’ synching.

Every lock in your arsenal – including Abus’s e-bike battery or frame locks – can use the same key, which is super convenient and unique to the German brand.

The hard plastic casing makes the lock slipperier and harder to pin down for attack. The thick coating not only hides progress and gums up the disc, it means the grinder knuckles out earlier so you have to switch the disc sooner.

Five minutes, including a second disc, got me 25-30% through, but that would equate to 40 minutes to cut through both sides.

Verdict: Big but not overly heavy, with keyed-alike convenience and great, multi-layer grinder resistance

Overall verdict

The Litelok X3, Hiplok D1000 and Abus Granit Super Extreme 2500 all casually resisted my attempts to cut through them. Most thieves would likely give up.

Yet the most secure award has to go to the Kryptonite New York Diamond Standard lock. It evaporated discs with barely a scratch to its ‘diamond’ inner layer, and the well-deserved reputation of its yellow colouring might stop thieves even trying.

In terms of the ‘failures’, the Litelok X1 would still take a thief more than five minutes to cut through enough to take your bike. While I managed to cut the OnGuard quickly, I’ve seen other tests where the coating was enough to toast the cutting disc without any lock damage, so you might be lucky there, too.

First published in Cycle magazine, December 25/January 26 issue. All information correct at time of publishing.