The first line of defence against the nightmare of bike theft is a solid and dependable bike D lock. The second line of defence is knowing how to lock your bike (properly), so thieves can’t make away with your frame and leave you with a sorry-looking wheel.
D locks (also known as U locks), come in many different sizes, materials, Sold Secure ratings, and price ranges. So, choosing the best D lock for your bike can be confusing if you don’t know what you’re looking for.
This blog should help you decide which D lock to buy and why it matters when it comes to insurance.
Why choose a D lock over other types of lock?
Of the three main types of bike lock – D lock, chain, cable. The D lock comes out on top for strength, reliability and popularity.
Its popularity is in part due to its portability and strength to weight ratio. A gold standard D lock is stronger than a cable lock, and far more compact and easier to carry than a heavy duty chain.
Lots of bike thefts happen from the garage, outbuilding or garden shed. If you’re securing your bike at home overnight or for long periods. A heavy chain and gold or diamond rated mini D lock will offer the highest protection (as long as it’s secured to a Sold Secure rated ground anchor). If you’re locking your bike when out and about. A gold or diamond rated D lock and cable is far more practical.
D locks can fit easily into a backpack or clip onto the bike for commuting, and the accompanying cable is light enough to sling over your shoulder or into your bag when riding, making it the go-to bike lock for regular cycle commuters.
What makes a lock, a D lock?
D locks, or U locks, are the most common types of bike lock. Their shape is similar to a traditional padlock, resembling the letter ‘D’ when the retaining bar is locked in place, or ‘U’ when unlocked without. The ‘U’ shaped steel shackle and locking barrel is robust for everyday use and a secure deterrent to thieves.
There are a range of manufacturers of bicycle D locks but the main ones are Kryptonite and Abus. D locks come in a range of security standards. They’re strong, reliable and easy to use, and whichever type of bike lock you use, most insurers, (us included), will specify the need for a lock appropriately rated for the value of your bike in order to validate your policy.
Remember: The Sold Secure rating is only applicable to the D lock itself. Not the accompanying cable so understanding how to lock your bike securely is key.
How to use a D lock
The downside of the D lock shape is that it can only fit around thin racks and posts (i.e. no lamp posts), but that’s why most come with a cable to secure the wheels as well as the frame.
The cable is easier to cut with hand tools that fit in your pocket however, so always make sure you secure your frame to the bike rack (and not just the wheels) as a bare minimum.
The best option if you have space and a big enough ‘U’ on the lock is to secure your frame and a wheel to the rack. Using the cable to loop around the other wheel so all points are secured. Angling the D lock through the frame and wheel onto the rack like this will leave little room for thieves to wedge a tool to prize it open, and make it harder to cut.
What is Sold Secure approval and why is it important?
Sold Secure approval is a security accreditation given to locks after being rigorously strength-tested by the Master Locksmiths Association. The rating is only given to the locking device and not the accessory cable, which can still be easily cut with the right tools but does offer extra protection for wheels to deter thieves.
The attack testing on the lock includes everything that a thief would try to steal your bike. Lock picking, manipulation, cutting and drilling with everything from basic pocket tools (screwdriver, hammer, hacksaw), to bolt croppers, drills, crowbars and power tools.
There are four different ratings (Bronze, Silver, Gold, Diamond). It’s this rating you should look for first when choosing a bike D lock due to its insurance requirements.
There will be some compromise in price, weight and portability the higher you move up the scale but we think it’s always worth carrying around the extra weight to keep your pride and joy safely where you left it.
Sold Secure ratings
The lock rating you need for your Bikmo insurance policy is based on the ‘as new’ bike value:
- Bronze: a bronze rated bike lock covers a bike valued up to £250 as new. Bronze locks typically fail the attack test in one minute so are a good defence against the opportunist thief.
- Silver: a silver rated bike lock covers a bike valued up to £251 – £1,500. They are heavier than bronze locks but lighter than gold. Silver rated locks fail the attack test in three minutes.
- Gold: gold rated bike locks offer maximum protection, covering a bike of any value and in excess of £1,500. Locks with gold Sold Secure certification withstand the attack test for five minutes or longer, so are a decent deterrent to put off even the most prepared thief.
- Diamond: A recent ultimate addition to the security accreditations. This is not a requirement for current Bikmo policy, but offers the highest possible security, more than Gold. Covering all bike values and withstanding an attack test of five minutes or more.
Tip: If you’re looking at buying a lock and are unsure if it’s suitable for purpose (or if you want to check the rating of your existing bike lock). You can check using the Sold Secure Approved Product Search.
Check out Bikmo’s locking requirements to keep your bike insurance valid:
The best bicycle D locks for 2023
There are some main players in the bike security market, and Kryptonite and ABUS locks feature heavily in our list of the best bike D locks for 2023.
Best Bronze rated D locks
D locks with a Bronze Sold Secure rating will cover bikes valued up to £250 new. However, you can usually find a Silver and Gold rated lock offering better protection for a little more in cost so it’s worth shopping around. If you do choose Bronze, the Kryptonite lock listed below is our pick.
Kryptonite Original Keeper D-Lock – RRP £19.99
Weight: 1.09kg
Dimensions: 4” x 8” (10.2cm x 20.3cm)
4/10 Security Rating
This is an affordable D lock with a compromise on strength for low to moderate crime areas. The 12mm hardened steel shackle on the Kryptonite Original Keeper D lock will resist the hand tools in the pocket of the opportunistic thief.
Get the Kryptonite Original Keeper D lock at Halfords for £19.99
Best Silver rated bicycle D locks
D locks with Silver Sold Secure rating will bikes valued upto £1500 as new. You can usually find Gold rated locks for the same price or a little more so it’s always worth seeing if you can get more protection for your budget. If you do go for Silver, below are our top picks.
Kryptonite Keeper 12 (The new Keeper) – RRP £29.99
Weight: 1.09kg
Dimensions: 10.2cm x 20.3cm
5/10 Security Rating
The Kryptonite Keeper 12 with Silver Sold Secure rating features a new hardened double deadbolt design with anti-rotation resist against twist as well as handheld tools.
Get the Kryptonite Keeper 12 on Amazon for £27.99
ABUS Ultra / Ultra Mini 410 – RRP £39.99 / £34.99
The ABUS Ultra is one of the top-rated Silver Sold Secure locks on the market and comes in two sizes for maximum portability. The lock has deadbolt locking and also features a plastic coating on the bolt to prevent paintwork damage when securing your bike.
Mini
Weight: 755g
Dimensions: 14cm x 8cm
8/10 Security Rating
A compact high-protection U lock that can fit in your back pocket, the ABUS Ultra Mini 410 features a 12mm thick rounded shackle made from specially hardened steel and a high quality double locking cylinder. The compromise on having the smaller sized shackle is limitations on locking the frame and wheel to the rack so worth bearing that in mind, and always take the cable for additional protection.
Get the Abus Ultra Mini 410 from Wiggle for £22.00
Standard
Weight: 1kg
Dimensions: 22cm x 36cm
8/10 Security Rating
The bigger brother of the Mini, the ABUS Ultra D lock standard size offers the same protection but with a longer shackle for easier securing.
Get the standard ABUS Ultra from Wiggle for £26.99
Hiplok D – RRP £49.99
Weight: 1kg
Dimensions: 7cm x 13.5cm
Security Rating: High
The Hiplok D is a pocket-friendly, high security, compact Silver rated D lock with a 13mm hardened steel shackle and rubberised outer to keep your frame scratch-free. The lock uses Hiplok’s patented CLIP+RIDE system to clip onto belts and bag straps, making it super portable, though this convenience comes at a compromise with a small locking area so you’ll only be able to lock the frame and not the wheel with this one.
Get the Hiplok D lock on Amazon for £44.99
Best Gold and Diamond rated bike D locks
If you require or are going for a Gold or Diamond, below are our top picks for this strength of lock.
Kryptonite New York Fahgettaboudit – RRP £119.99
Weight: 2.06kg
Dimensions: 8.3cm x 15.3cm
Security Rating: 10/10
The New York Fahgettaboudit is the strongest D lock made by Kryptonite and scores 10/10 on their security rating. The 18mm hardened max-performance steel shackle and small ‘U’ area resists bolt cutters and leverage attacks, and is pick and drill resistant.
The oversized ultra strong crossbar using Kryptonite’s patented hardened steel sleeve offers double security and it comes with three keys which you can register for replacements in case you lose them. The Fahgettaboudit lock comes in a mini size or you can get the Kryptonite New York Standard lock which is also gold rated.
Mini:
Get the Kryptonite New York Fahgettaboudit Mini on Amazon for £90.76
Standard:
Get the Kryptonite New York Fahgettaboudit Standard from Halfords for £109.99
Kryptonite Evolution – RRP £69.99
Weight: 1.59kg
Dimensions: 10.2cm x 22.9cm
8/10 Security Rating
The Kryptonite Evolution D lock is our second best pick in the best gold and diamond standard D locks, featuring a 14mm hardened max-performance steel shackle and patent-pending hardened double deadbolt design for additional protection against twist attacks. The new smaller crossbar design is a bit more portable than the New York, and you get three keys with this lock too that you can register in the Key Safe Program.
Get the Kryptonite Evolution D lock on Amazon for £39.64
Onguard Pitbull – RRP £48.00
Weight: 1.6kg
Dimensions: 11.5cm x 29.2cm
Security Rating: High
With a name fierce enough to put off any prospective bike thief, the Onguard Pitbull D lock offers superior protection for medium to high crime areas at a fraction of the price of other gold standard locks. A hefty 14mm thick hardened steel shackle resists cutting, prying and jacking, and the lock has also withstood pucking, pulling and drilling tests too.
Get the Onguard Pitbull from Tredz for £28.99
Hiplok DX – RRP £79.99
Weight: 1.1kg
Dimensions: 8.5cm x 15cm
Security Rating: Maximum
Now Diamond rated, the Hiplok DX D lock is the Hiplok D’s maximum-security upgrade. This compact D lock is super portable, using the same patented CLIP+RIDE system to clip onto belts and bag straps, and a 14mm premium hardened steel shackle and anti-rotation locking system has withstood the toughest of attacks to gain the highest Sold Secure rating.
Get the Hiplok DX lock from Wiggle for £79.99
Insurance
Choosing the best D lock to buy for your bike and insurance policy can be a big job, but we hope this guide has been helpful. We think it’s always worth carrying the extra weight of a decent bike lock so you don’t have to carry the weight of a broken heart if your pride and joy gets stolen!
If the first line of defence is a decent bike lock, and the second is knowing how to lock it properly, the third is definitely bike insurance, just in case the worst does unfortunately happen. Get in touch for a quote.
Need more help with your bike security? Check out our guides, from an insurer’s perspective:
