How much is too much to spend on security? If it’s to protect something as valuable and as important to you as your bicycle, then no amount of money is overdoing it.
Which is why, if you’re looking for a dependable bike lock to put off potential thieves while you leave it unattended, there are few better answers to this conundrum than a Sold Secure lock.
They’ve recently added a fourth tier to their lock security ratings: Sold Secure Diamond, which immediately comes in at their highest ranking. Let’s take a look at our top three, as well as some highly-recommended D-locks and mini D-locks with the same ‘Diamond’ rating.
Indeed, it’s worth noting that as this new security certification is still so new, some locks mentioned in this guide are still advertised at their previous “Bicycle Gold” level, despite having now been bumped up to the Diamond tier.
High Security Bike Locks
There can be some many different questions to consider when picking the right bike lock for you. How big is it? How thick is it? How heavy or versatile is it? Is the metal of a particularly high quality?
With Sold Secure, though, you know exactly what you’re getting from minute one – high-quality bike security from independent lock-checkers who certify each lock’s qualities.
Even the lowest of their four levels, bronze, which will ‘typically offer defence against the opportunist thief’ is worth your time, as it’s still certified, unlike most other cheap bike locks.
What is Sold Secure “Diamond”?
Sold Secure Diamond is the highest certified level of security, and aimed at bicycles and e-bikes of the highest value.
Previously, Sold Secure offered three tiers – gold, silver and bronze – but diamond surpasses them all, and are perfect for anyone living in big, bustling urban towns and cities, or on university campuses.
With more and more bike locks seeming to earn a Gold rating year on year, the Diamond rating will help the very best to stand out just little that bit more, and are especially helpful if your bike is particularly expensive and/or attractive, or if you plan on leaving it unattended for longer than one hour.
Sold Secure: Diamond v Gold
This could be confusing at first because many bike locks deserving of a Diamond rating will remain Gold until they’ve passed testing phases to move up a level.
You may also buy a Diamond-rated lock which is packaged as Gold, given the relatively new arrival of the Diamond level.
But as a general rule, though, you’ll find that the a Diamond Secure bike lock will offer a metal thickness of between 14 and 18mm, can weigh anything from roughly three to 15 lbs, can be as tall as 60 inches or as small as five inches, and is normally between three and four inches wide.
NOTE: This page contains affiliate links, meaning I may receive commissions for purchases made through those links, at no cost to you. This helps to keep the wheels of Discerning Cyclist turning.
We’ll start by looking at three of the best D-locks, but you can skip ahead to the best chain locks by clicking here.
Sold Secure Diamond D-Locks [Top 3]
Most Secure D-Locks to Protect Your Bike
One of the most secure bike locks in the world
- Metal thickness: 16mm
- Weight: 5.95 lbs (2.70 kg)
- Size: 10.2” x 4.4” (26 cm x 11.1 cm)
A big, bulky, double-bolted model made of hardened steel, this Abus Granit Extreme 59 bicycle D-Lock is enormous and perfect for keeping any larger bicycles safe from thieves.
With its 16mm square parabolic shackle to boot, your bike could hardly be safer, while an Abus XPlus cylinder also increases protection against tampering.
It’s also extremely easy to carry around with you, too; just attach it to tubes with a diameter of 12-17mm using the SH 59 bracket and you’re good to go.
A great value, lightweight and extremely sock U-lock
- Metal thickness: 14mm
- Weight: 2.38 lbs (1.08 kg)
- Size: 10.1” x 4.0” (25.6 cm x 10.2 cm)
This blue high security bike U-lock boasts a 14mm shackle of hardened steel, and offers reliable protection no matter how busy or dangerous an area you leave your bike in.
It also comes with a shock-resistant rubber over-molded lock body and an ultra-secure double-locking mechanism which is pick-resistant – to make any opportunistic thief’s job that bit harder.
And if you lose your key, no problem – it comes with three of them, and Oxford offer their own key replacement service if need be, too.
Best Mini D-Lock with Diamond Rating
The toughest, most secure mini bike D-lock
- Metal thickness: 18mm
- Weight: 4.55 lbs (2.06 kg)
- Size: 6.0” x 3.25” (15.3 cm x 8.3 cm)
With this bright yellow mini bike D-lock (rated 10/10 on Kryptonite’s security scale), your unattended bike could hardly be in safer hands, thanks mainly to its highest security, disc-style cylinder, which is pick and drill-resistant.
Its double deadbolt design offers extra protection from twist attacks, while its 18mm hardened steel shackle provides some serious beef. A patented steel sleeve only enhances its security levels, too.
A chunky Kryptonite D-lock which suits both male and female bikes, don’t be fooled by its seemingly smaller design – it’ll be almost impossible to break through this.
- 18mm hardened MAX-Performance steel shackle resists. Product weight- 2.06 kgs
- Double deadbolt design gives additional protection against twist attacks
- Highest security disc-style cylinder is pick and drill resistant
Sold Secure Diamond Chain Locks [Top 3]
Most Secure Chain Locks for Your Bike
Different sizes but equally as sturdy
- Metal thickness: 13mm
- Weight: 11.2 lbs (5.1 kg)
- Size: Comes in lengths of 1.2m, 1.5m or 2.0m
Whatever length you prefer this chain lock (1.2m, 1.5m and 2m are your options), this high-security chain and padlock is bound to do a sterling job of keeping petty thieves away from your bike.
With this updated model, its square links have increased in size from 12mm to 13mm, making this bike security chain just that little bit more imposing. What’s more, when riding, this cloth-covered chain can easily be stashed away under your bike seat without any fuss.
Plus, it comes with an ultra-strong padlock with hardened boron steel armour casing, a double-locking mechanism, and an 11mm shackle; all of which makes it arguably the most secure chain lock going currently.
- High security chain and padlock
- The UK's biggest selling, Thatcham approved chain & padlock just got stronger!
- Increased size of square links from 12mm to 13mm, makes the chain an even stronger deterrent.
An extremely secure bicycle chain lock
- Metal thickness: 16mm
- Weight: 19.80 lbs (9 kg) (in the 2.0m length)
- Size: Comes in different lengths – 0.6m, 0.8m, 1.0m, 2.0m
Whatever size you prefer this chain lock in, it can not only deter thieves from stealing bikes, but can also be just as effective with motorcycles, trailers, caravans and much more.
With an impressive 16mm thickness, it will be impossible to bolt-crop the chain by hand, and the fact it has been boosted Sold Secure Diamond status should only sweeten the deal for you.
The use of long links throughout the chain’s length also lends itself to a lighter feel, providing more versatility in the process and allowing the chains to be used with close shackle padlocks for maximum security.
Forget about thieves with this Sold Secure Diamond chain lock
- Metal thickness: 14mm
- Weight: 10.80 lbs (4.90 kg)
- Size: 39” (100 cm)
Also available in a longer, 150cm length, this Kryptonite bike chain lock has been approved to Sold Secure Diamond standard, so you already know it’s worth putting your trust in.
With 14mm six-sided chain links made of hardened Manganese steel, this lock could hardly get any stronger – well, apart from through its New York Disc Lock with 15mm maximum performance steel shackle, anyway.
This Diamond secure bike lock also has a durable nylon cover with hook-and-loop fasteners to keep it in place, and on top of that, it comes with three stainless steel keys – one lit with a high-intensity bulb – and a replaceable battery.
- Approved to bicycle Gold Sold Secure standard
- 14mm six-sided chain links made of 3t hardened Manganese steel for ultimate strength
- Includes maximum security New York Disc Lock with 15mm max-performance steel shackle
Bicycle Locks – FAQs
What does “Sold Secure” mean?
Sold Secure itself is the premier testing and certification house for security products. Any lock certified by them has been tested and approved, meaning it’s guaranteed to be a quality investment.
How much should I spend on a bike lock?
There’s a sense of a false economy about buying bike locks; certainly the cheaper ones, anyway. It can be tempting not to blow your entire budget on one because there are more cost-effective alternatives, but if it isn’t good enough to protect your bike, you’ll lose even more money if it’s stolen.
As a rule of thumb, look to spend at least ten per cent of your bike’s value on its lock.
How to carry a D-lock on your bike?
Fortunately, most D-locks will come with their own clamp, which you can then attach to your bike frame.
If so, mount it high in the seat tube, in the middle of your down tube or the underside of the top tube, to keep it out of the way but still easily accessible if and when you need it.
What’s the best way to lock your bike?
Lock your frame to the immovable object, keeping the lock away from the ground so a thief can’t use a hammer to smash it against the floor. Make the lock as inaccessible as possible, especially by positioning it so they keyhole faces downwards.
Plus, if you use a U-lock, fill as much of the inside space as possible, so leverage attacks from thieves (e.g. twisting the inside with a pole until it opens) are off the cards.