The UK reported 66,960 bicycle thefts in the year ending March 2024.1 Among bikes stolen while locked, cable locks appear in 35% of theft reports versus 26% for U-locks.4 That gap reflects what independent testing shows about different lock types. Understanding each u lock security rating system, specifically how Sold Secure, ART, FUB, and Varefakta work and differ, gives you a factual basis for comparing products across manufacturers. For the broader context on U-lock selection, see the overview at Bike U-Locks: Everything You Need to Know.
Quick Answer
What does a u lock security rating from Sold Secure, ART, or another certification body actually mean?
Each certification grade reflects how long a lock resisted a standardized attack using defined tools. Sold Secure uses four pedal cycle levels: Bronze, Silver, Gold, and Diamond. ART (Netherlands) uses one to five stars. FUB (France) and Varefakta (Denmark) each apply their own verified marks. Sold Secure Gold represents around five minutes of resistance against heavy-duty hand tools.2 These independent marks are the only common standard for comparing U-locks across manufacturers fairly.
Key Takeaways
- UK bicycle insurers most commonly require Sold Secure Silver for bikes worth up to £1,500 and Gold or higher for more valuable bikes.3
- ART and Sold Secure ratings are independent systems with different test protocols. Their levels do not directly correspond to each other.
- A U-lock carrying no independent certification mark offers no verifiable resistance benchmark, regardless of what the brand's internal scale says.
What You Need to Compare Ratings
Before working through the steps below, have the following ready:
- The name and exact model of any U-lock you want to verify
- Internet access to reach the Sold Secure product database at soldsecure.com and the ART database at stichtingart.nl
- Your bicycle insurer's policy documents, or the summary page that states which certification level the policy requires
- Five to ten minutes per lock
No technical knowledge is required. The certification databases are public and free to search. The only prerequisite is knowing which lock you want to check.
Step 1: Learn What Certification Tests Actually Prove
By the end of this step, you'll understand what separates an independently certified rating from a brand's internal security label, and why that distinction changes how you compare U-locks.
Independent bodies versus brand scales
An independent certification body is a third-party organization that tests locks with no commercial stake in the outcome. Sold Secure, ART, FUB, and Varefakta all fit this description. Each one runs attack tests with defined tools and time limits, then lists which products passed. A maker must resubmit their product if the design changes after testing.
Brand scales work differently. Most brands assign scores on a 0-to-10 or 0-to-15 axis with no external check. Because no two brands use the same scale, a top score from one brand says nothing useful about a top score from another. The scales do not align, which makes them useless for cross-brand comparison.
The practical point: a lock's independent certification mark is the only score that means the same thing across brands. A brand's own number cannot make that promise.
What a certification test actually measures
A certification test measures resistance to a simulated attack. Testers use the specific hand tools, power tools, and techniques listed in the standard, apply them to the lock, and time how long the lock holds. The rating reflects what passed that test under those exact conditions.
This matters most when comparing U-locks from different brands. If both carry Sold Secure Gold, each survived the same Gold attack test. If one shows a brand's "Level 10" and another shows a brand's "Level 8" with no independent mark, no valid comparison exists. The scores measure different things.
A certificate is not just a label. It is proof that a lab tested this exact lock and recorded the result. A brand's own number cannot say the same.
One thing a certification test does not tell you: it cannot predict every real theft. The test is a repeatable benchmark. It does not promise that a thief will fail. Its value is comparative. Two locks that passed the same test can be compared. A certified lock and an uncertified one cannot.
Step 2: Read a U lock Security Rating from Sold Secure
By the end of this step, you'll know what each Sold Secure pedal cycle level means and how UK insurers use those levels to set their coverage requirements.
How Sold Secure works
Sold Secure is a UK testing and certification body. It was founded in 1992 by Northumbria and Essex Police with Home Office backing, and is now owned by the Master Locksmiths Association.2 Its Pedal Cycle ratings are the most widely used standard for bicycle locks in the UK and are the benchmark most UK insurers name in their policy documents.
Sold Secure issues four rating levels for pedal cycle locks.2 In order from least to most demanding:
| Level | Attack complexity | Typical UK insurer acceptance |
|---|---|---|
| Bronze | Short attack, single easily-concealed hand tool | Some policies for low-value bikes |
| Silver | Longer attack, enhanced tool list | Most policies for bikes up to £1,500 |
| Gold | Extended attack, heavy-duty tools, around five minutes | Required by most for bikes over £1,500 |
| Diamond | Extended attack with power tools and machine-based testing | Required by some for highest-value bikes |
Sold Secure does not publish the exact time thresholds for Bronze or Silver. The organization keeps specific test parameters unpublished to prevent attackers from calibrating their technique to the test boundary. What the ratings do confirm is the relative attack complexity: each step up means a more aggressive and more time-intensive simulated attack.
What each level means for insurance coverage
UK cycle insurers routinely specify which Sold Secure level they require. Yellow Jersey Insurance is direct about the stakes:
"If your lock doesn't carry a Sold Secure rating, we're unable to provide coverage for your bike."
Yellow Jersey Insurance, bicycle theft coverage policy, April 20253
Their policy requires Sold Secure Silver for bikes worth up to £1,500 and Gold for bikes worth more than that.3 Other UK insurers apply the same structure. Diamond is required by some policies for the highest-value bikes or for e-bikes, where the replacement cost makes the highest attack resistance the relevant threshold.
Check your specific policy documents for the exact level required. The figures above reflect common practice, not a universal rule.
How to verify a U-lock's current Sold Secure rating
Look for the Sold Secure logo on the lock's packaging or the product listing. Then check the Sold Secure database at soldsecure.com. The database lists every certified product. A lock not found there has either never been certified or needs retesting after a design change.
Certification can lapse if a maker updates the lock without new tests. The database is the record to trust, not the packaging.
The Mason 180 and the Mason 220 are both Sold Secure Diamond despite their different shackle lengths.2 This shows the test focuses on build quality, not lock size.
Checking the database takes two minutes. That check is the difference between a verified certification and a stale packaging claim.
Step 3: Decode an ART Star Rating
By the end of this step, you'll understand the ART system and know when it applies to you.
What ART tests and certifies
ART (Stichting ART, the Dutch Foundation for Cycle Lock Quality) is the Netherlands' independent bicycle lock certification body. It uses a one-to-five-star scale where higher stars reflect greater resistance to attack.
ART locks are tested by the independent laboratory SKG-IKOB Certificatie BV across more than twenty assessments, including freezing, dust, corrosion, endurance, cutting, tensile strength, and direct attack tests.5 The breadth of the test suite is broader than most people expect when they see a star label on a lock.
The ART star levels work as follows:5
- ART 1 to 2 stars: The lock must withstand several lock-picking attempts with simple tools for a couple of minutes.
- ART 3 to 4 stars: The lock must withstand attempts with specialized tools for a couple of minutes. Brute force attacks are often included.
- ART 5 stars: The lock must withstand lock-picking, hacking, and forcing for a longer time using heavier tools.
ART certification carries direct insurance weight in the Netherlands. Dutch bicycle insurers require at least ART 2 stars for all bicycles.6 Mopeds need ART 3 stars. Motorcycles need ART 4 stars. The scale covers all vehicle types, not only bicycles.
If you ride in the Netherlands, ART star level is not optional. Your insurer sets a floor, and a lock below that floor means no payout if your bike is stolen.
ART and Sold Secure are not directly equivalent
The two systems use different scales, different labs, and different attack rules. A Sold Secure Gold and an ART 3-star rating are both solid benchmarks, but they do not map onto each other. Do not assume they are equal just because they sit at similar positions in their own scales.
A product with both certifications has been tested in two labs under two different standards. That dual result is a stronger base than either mark alone. In the Netherlands, ART is what insurers require. In the UK, Sold Secure fills that role. Where a lock carries both, each rating stands on its own.
Step 4: Recognize FUB and Varefakta Marks
By the end of this step, you'll know which independent marks apply in France and Scandinavia, and what each requires of a certified U-lock.
FUB (France)
FUB is the Fédération française des Usagers de la Bicyclette, the French cyclists' federation, which has operated an independent annual lock testing commission since 2003.7 FUB awards two certification levels for bicycle locks:
- FUB 1 Roue: Resists quick attacks with small, concealable tools under 30 cm.7
- FUB 2 Roues: Resists larger, more aggressive tools under 75 cm over a longer attack period.7
French bicycle insurers most commonly recognize only the 2 Roues level for theft coverage. If your insurer is French and your policy requires FUB certification, confirm that the lock carries the 2 Roues level specifically. The 1 Roue level may not satisfy the policy condition.
FUB maintains a list of currently recommended locks on its website. As with Sold Secure and ART, a packaging claim is not sufficient without checking the official list.
Varefakta (Denmark and Scandinavia)
Varefakta is a Danish independent certification body that tests bicycle locks to standard VF 5029:4, covering six lock categories: ring locks, U-locks, chain locks, foldable locks, loose U-locks, and handlebar locks.8
Attack tools in the Varefakta test include screwdrivers, pliers, wrenches, and saws. Methods include twisting, sawing, cutting, and forced cylinder extraction. Varefakta certification also includes cold weather testing at minus 20 degrees Celsius.8
Danish bicycle insurers typically require a Varefakta-approved lock for theft coverage. The certification mark must appear on the lock, and the retailer documentation supplied at purchase must confirm the approval.8 This means the purchase receipt matters: keep it with your insurer's policy documents.
Neither FUB nor Varefakta uses the same scale or test protocol as Sold Secure or ART. A U-lock that carries marks from all four bodies has been independently tested to four different standards.
Step 5: Cross-Reference a U-Lock with Multiple Certifications
By the end of this step, you'll know how to read a product that carries marks from more than one certification system.
What multiple marks mean
Some U-locks carry certifications from more than one independent body. This is most common for products manufactured for international markets. When you see multiple certification marks on a single product, each mark represents an independent test. They do not add to each other or cancel each other out.
The practical benefit is greater evidence coverage. A lock with both Sold Secure Diamond and ART 3 stars has been tested in two independent labs under two different attack protocols. For a cyclist buying from an international retailer, dual certification also confirms that the insurer in their home country will likely recognize the relevant mark.
What to look for on a product page
Look for specific certification names and levels. Terms like "high security," "professional grade," or "maximum protection" are not certifications. A genuine certification claim names the body (Sold Secure, ART, FUB, Varefakta) and the level (Gold, Diamond, 3 Stars, 2 Roues).
If only one certification appears, that is the only mark that lock has earned. Check the maker's page and then the certification body's database to confirm the rating is current for that exact model.
A lock listing "Sold Secure Gold" and "ART 3 Stars" has passed two attack tests. A lock listing one certification and then a brand score has passed one. They are not the same.
One brand's internal color scale that maps directly to certification
Seatylock's internal color scale (Silver, Gold, Diamond, Armored) maps directly to Sold Secure levels, so an internal badge always matches an official certification. A Gold badge means the lock holds Sold Secure Pedal Cycle Gold. This removes the gap that usually makes internal scales useless for comparison, but it applies only to Seatylock products. Other brands' internal scales carry no such promise.
Step 6: Match the Rating to Your Risk Level
By the end of this step, you'll have a framework for choosing which certification level is right for your specific parking situation.
Three factors that determine the right level
Matching a certification level to your needs requires honest assessment of where you park, how long you leave the bike, and what the bike is worth.
Short stops in low-theft areas: Sold Secure Silver or ART 2 stars is a reasonable floor. These cover the quick opportunistic attacks that account for most casual thefts. For riders in the Netherlands, ART 2 is also the legal minimum for insurance coverage.6
Longer parking in city centers, transit hubs, or university campuses: Sold Secure Gold is the appropriate target. The test for Gold covers around five minutes of resistance with heavy-duty tools, which is typically longer than a thief will work in a visible public location.2 Most UK insurers require this level for bikes over £1,500.
High-value bikes or overnight outdoor parking: Sold Secure Diamond or ART 4 to 5 stars. These levels include power tool testing. That matters when the parking location gives a thief uninterrupted time, such as a communal storage area or a dark street overnight.
Size and certification are separate questions
A U-lock's internal dimensions affect how much unused shackle space a thief can exploit for leverage, but dimensions do not determine the certification level. A compact U-lock reaching Sold Secure Diamond offers the same independently verified attack resistance as a longer one with the same rating. Choosing the right shackle size for your bike and anchor is a separate decision. For guidance on measuring frame width, wheel clearance, and anchor reach, see the U-lock size guide.
For an e-bike, the same logic applies, but the higher replacement value makes Sold Secure Diamond or ART 3 stars and above the practical minimum for most riders. The article on U-locks for e-bikes addresses frame fit and rack clearance for heavier bikes in more detail.
The Mason 140 is a compact Sold Secure Diamond U-lock suited to low-clearance locking situations, where minimizing unused shackle reduces leverage opportunities while keeping the same certification level as larger models in the range.
Common Mistakes When Reading Lock Ratings
Treating a brand's internal scale as a certification
The most common error is reading a brand's "Level 10" or "Security Rating 15" as if it were equal to Sold Secure Gold. Internal scales are not set to any shared standard and are not tested by an outside lab. Two locks with the same internal score from different brands have not been tested to the same standard. There is no way to know what each score means without independent certification.
Assuming a higher internal number always means a certified product
A brand's maximum internal score may correspond to no independent certification at all. The score reflects the manufacturer's own assessment rather than a third-party test result. Until a certification body has tested the lock and listed it in their database, the internal number is unverifiable.
Comparing Sold Secure levels to ART stars as if they were parallel
Bronze, Silver, Gold, and Diamond are Sold Secure levels. ART 1 through 5 stars are ART levels. The two systems are not aligned, and a Sold Secure Gold is not equivalent to ART 3 simply because they occupy similar positions in their respective scales. Compare products within the same certification system when making a direct comparison.
Accepting the packaging claim without checking the database
Certification marks appear on packaging, but a model's design may have changed since its last test. Both Sold Secure and ART keep online databases updated when certifications are granted or lapse. A two-minute database check confirms the rating applies to the exact current model. The packaging alone does not.
Ignoring FUB and Varefakta outside the UK
Riders in France and Denmark who rely only on Sold Secure or ART marks may find their insurer does not recognize them. FUB and Varefakta are the standard of reference in those countries. Confirm which body your insurer recognizes before buying, since a lock that satisfies one country's insurer requirement may not satisfy another's.
What You Can Confirm Once You Know the System
After these steps, checking any U-lock claim takes about five minutes. Search the certification body's database, confirm the level, then match it to your insurer's needs and your parking situation.
Certified U-locks share a consistent base. A lock with Sold Secure Diamond has passed the same test as every other Sold Secure Diamond product, no matter who made it. That shared standard is what makes certification the useful tool for comparison, while brand-internal scales cannot serve that function.
Five minutes of database checking beats an hour of trying to compare brand scores that do not share a common scale.
A certified U-lock works best with good locking technique. See the guide on locking your frame and rear wheel to a fixed anchor for how to place the shackle, cut unused space, and reduce leverage points.
Frequently Asked Questions
Is Sold Secure Diamond better than Sold Secure Gold?
Yes. Diamond is the highest Sold Secure pedal cycle level and includes power tool and machine-based testing in its attack protocol, while Gold tests against heavy-duty hand tools over around five minutes.2 Diamond is designed for high-value bikes and locations where a thief may have uninterrupted time. Gold remains the level most UK insurers require for bikes over £1,500.
Is ART certification recognized by UK insurers?
UK insurers specify Sold Secure levels, not ART stars, so ART certification alone does not satisfy a UK policy's lock requirement.3 However, a U-lock carrying both ART and Sold Secure ratings has been tested under two independent standards. For UK coverage, confirm the Sold Secure level separately from the ART mark.
How do I check if a specific U-lock is currently certified?
Search the certification body's own product database. Sold Secure's database is at soldsecure.com and ART's is at stichtingart.nl. Enter the lock's model name and verify the level shown. Packaging claims can become outdated when a product is updated after its last test, so the database is the authoritative source.2
What is the minimum Sold Secure rating most UK insurers require?
Most UK bicycle insurers require Sold Secure Silver for bikes worth up to £1,500 and Sold Secure Gold for bikes valued above that threshold.3 Some policies require Gold regardless of bike value, and a few require Diamond for the highest-value bikes. Your policy documents state the exact condition. A lock without any Sold Secure rating generally invalidates a theft claim.
Does a Sold Secure rating apply equally to all U-lock brands?
Yes. Sold Secure tests and certifies locks from any manufacturer that submits products to its laboratory. The same attack criteria apply regardless of brand.2 A Sold Secure Gold U-lock from any manufacturer passed the same Gold test. Brand identity does not change the test standard, which is precisely what makes Sold Secure ratings useful for cross-brand comparison.
Limitations and Edge Cases
- Bicycle theft figures in this article are from England and Wales (ONS, year ending March 2024). Theft rates and patterns vary significantly by region and country.
- Insurance requirements listed reflect the published policies of specific named UK insurers as of 2025. Your specific policy may differ. Confirm the required certification level with your insurer directly before purchase.
- The Varefakta attack resistance figures referenced in this article come from manufacturer documentation citing the VF 5029:4 standard. Confirm exact current thresholds against Varefakta's published specification at varefakta.dk before relying on any specific figure.
- FUB insurer recognition of the 2 Roues level reflects commonly cited practice. French insurers set their own policy conditions, so confirm with your specific insurer that FUB 2 Roues meets your policy requirement.
References
Methodology: every figure in this article is drawn from an independent published source and links to the page that carries it; the article was reviewed by Shahaf Levavi, Head of Product at Seatylock, and is updated when certification standards change.
- Office for National Statistics - Nature of Crime: Bicycle Theft, Dataset, year ending March 2024, released March 2025.
- Sold Secure - Pedal Cycle Rating Levels, official product certification database, Master Locksmiths Association, current edition.
- Yellow Jersey Insurance - Bike Theft Insurance: Does Your Lock Meet the Standard?, April 3, 2025.
- BikeIndex - 2025 Bicycle Theft Stats: What You Need to Know, February 6, 2025. Primary data: Cohen et al., Findings Journal (2023), DOI 10.32866/001c.90056.
- Stichting ART - About the ART Quality Mark, official certification overview, Stichting ART Nederland, current edition.
- Stichting ART - ART and Insurance, insurance requirement overview, Stichting ART Nederland, current edition.
- FUB - Anti-Theft Lock Commission, Fedération française des Usagers de la Bicyclette, current edition.
- Fonden Varefakta - Bicycle Locks, standard VF 5029:4, Fonden Varefakta, current edition.
Conclusion
Sold Secure, ART, FUB, and Varefakta each give verified proof of what a U-lock survived in a controlled attack test. No brand's internal scale can match that. No internal scale uses the same criteria across brands. Read the certification level on a U-lock. Check it in the certification body's database. Match it to your insurer's requirement. That is the only reliable way to compare locks from different brands.
For the full context on how U-locks fit into a wider security approach, see the overview at Bike U-Locks: Everything You Need to Know.
