For a bike left on the street, buy a D-lock with a Sold Secure Gold or Diamond rating, add a second lock of a different type, and fit them tightly to the frame and an immovable anchor. No lock is theft-proof, and a rating is a way to compare locks you cannot test yourself. This page helps you choose the lock. For the lock-up routine itself, see How to Lock Your Bike So It Won’t Get Stolen.
What the Sold Secure ratings mean
Sold Secure is a UK testing and approval body, and its grades (Bronze, Silver, Gold, Diamond) appear on many locks. Its tests cover attacks such as angle grinders, drilling, cutting, levering and picking. Used as a ladder, the grades work like this.
| Rating | Typical products | What the rating tells you |
|---|---|---|
| Diamond | Many D-locks, plus chains and ground anchors | The top tier, with resistance to prolonged attacks; more than 100 bike locks hold it |
| Gold | Many D-locks, some chains | Protection against a wide range of attacks lasting around five minutes |
| Silver | Locks aimed at balancing security with cost | Costs significantly less than higher grades, with a little less protection against a determined thief |
| Bronze | Cable locks, folding locks, some D-locks | Stops an opportunist walking away with the bike, but not a determined, experienced thief |
Treat a rating as a comparison between locks, not a guarantee. Two cautions apply. A rating can cover only part of a product: where a D-lock is sold with a cable that loops through it, the rating applies to the D-lock and not the cable. And even the top grades are not a promise: professional thieves can eventually break pretty much any lock, and angle grinders are a popular tool for them, so a lock buys time and raises the effort required. Sold Secure’s own site lists approved pedal-cycle products by grade, so you can confirm a specific lock’s rating there before buying.
Two widely reviewed D-locks compared
These two are examples of the heavy end of the market, with figures taken from the reviews named. Ratings and weights vary by version and by retailer, and the Bennetts review dates from 2018, so confirm the exact product on the Sold Secure listing before buying.
| Lock | Rating per the review | Weight | Price in the review | Notable result |
|---|---|---|---|---|
| ABUS Granit XPlus 540 | Sold Secure Bicycle Gold (Bennetts review) | 1.47 kg (3.2 lb) | £98.99 at the time of the February 2018 review; current price will differ | In Bennetts’ testing only an angle grinder defeated it |
| Kryptonite New York Fahgettaboudit Mini | Sold Secure Gold (OutdoorGearLab review) | 4.5 lb (about 2.0 kg) in the spec table; the verdict says 4.7 lb | $180 list price given in the review; check the current price | Small shackle opening can be awkward for mountain bikes or fat-tired commuters |
The pattern matters more than the names: a lock around 1.5 kg and one around 2 kg can sit in similar grades, so weight is a carrying cost you pay, not a direct measure of security. If a lock does not fit around your frame and a fixed anchor, a stronger grade will not help.
Choosing by lock type
- D-lock (U-lock): the usual primary lock for commuters. Many Gold and Diamond products are D-locks, and many come with a mount for carrying on the bike.
- Chain lock: the most secure chains tend to be heavy with hardened links. They suit a lock you leave at a fixed destination rather than carry daily.
- Folding lock: easier to carry, but the joints are the vulnerable point, so look for a high rating rather than assuming the type is strong.
- Cable lock: on its own, unlikely to be as secure as a chain or D-lock. Use it to tie a front wheel or accessories to the main lock, not as the only protection.
Match the rating to your situation
These are practical judgments built on the tiers above, not rules from a standard.
| Where the bike stays | Reasonable starting point |
|---|---|
| Public racks, several hours, bike costly to replace | Diamond, or Gold at minimum; the rating guidance points to Gold for long periods in public areas and Diamond for high-value bikes and e-bikes in high-risk places |
| Same workplace daily | A heavy, high-rated lock or chain kept at the destination, with a lighter lock for other stops |
| Home shed or garage | Lock the bike even at home, because thefts from sheds, garages and back gardens are common |
| Very short stop, cheap bike | Silver may be enough; Bronze only deters opportunists |
A heavier lock is a lock you may leave at home, so pick the heaviest one you will carry every day. E-bikes raise the stakes because battery and motor add value; see E-Bike vs Regular Bike for how commuting differs.
Use two different locks
If you carry more than one lock, make them different types, such as a D-lock and a chain, or a key lock and a combination lock. A thief may have the means to break one but not the other.
Fit and technique
A good lock fitted badly still fails. The routine for anchors, tight fit and lock position is covered in the lock-up guide; the rest of a commute setup is in How to Make Cycling to Work Actually Work and converting a bike to a commuter.
Register the bike before it is stolen
Record the serial number and register it. Bike Index describes itself as the non-profit bike registry, and registration asks for your name, bike manufacturer, serial number and component information.
Sources
- BikeRadar: Sold Secure bike lock ratings explained
- BikeRadar: How to lock a bike properly
- Bennetts BikeSocial: Abus Granit XPlus 540 U-lock review
- OutdoorGearLab: Kryptonite New York Fahgettaboudit Mini review
- Sold Secure: Security Product Testing & Approval
- Bike Index: The non-profit bike registry
Last reviewed: October 2026.