A good lock only helps if it is used well. This guide pulls together what the U.S. Justice Department’s COPS Office guide on bicycle theft says about how bikes get stolen and how to lock them, what Sold Secure’s ratings mean, and Bike Index’s steps for registering a bike and acting after a theft.
Why locking practice matters more than the lock alone
According to the U.S. DOJ COPS bicycle theft guide, offenders use techniques that are directly linked to how a cyclist applies a lock. When a bike is unlocked or poorly secured, little skill is required to steal it. The guide notes that in cases where a cyclist locks only one part of the bicycle, an offender may exploit the opportunity to steal the rest. At one university, for 22 percent of cycle thefts, only the lock and secured wheel remained at the crime scene.
Research cited in the same guide examined roughly 8,500 London bicycle-locking events and found that 87 percent of cyclists used only one lock, 19 percent locked only their frame to the stand, and just 20 percent locked in a way considered “secure.” The guide defines secure locking as the application of an appropriate lock or locks to secure a bicycle’s wheels and frame to a stand. Of 180 possible locking configurations to a standard Sheffield stand, researchers categorized 109 as bad or insecure, 48 as OK or semisecure, and only 23 as good or secure.
Poor locking practices ensure a constant supply of available targets, the DOJ guide explains. Observing more-secure locking practices should, at the very least, reduce opportunistic crime. If you are choosing a lock, understanding how security ratings work is a practical first step. Our bike locks guide walks through the main types, and the bike lock security ratings explained article covers what each certification means.
What Sold Secure ratings tell you about a lock
Sold Secure rates bike locks under its Pedal Cycle category with four grades: Diamond, Gold, Silver, and Bronze. According to the Sold Secure Pedal Cycle ratings guide, each rating indicates how well a product resists specific threat levels and the different attack methods used by thieves. Diamond is the highest grade, followed by Gold, Silver, and Bronze.
Sold Secure states that Pedal Cycle Diamond offers the highest level of resistance against the most determined bicycle thief and is intended for very high value pedal cycles kept in very high risk areas. Its attack uses an extended list of heavier-duty tools, including some power tools. Pedal Cycle Gold provides a high level of resistance against the dedicated bicycle thief and is recommended for high-value bikes kept in high-risk areas such as a big city or university town. The attack uses heavy-duty tools, but a shorter tool list than Diamond.
Pedal Cycle Silver, Sold Secure explains, gives a greater level of resistance against the more determined thief and is ideal for lower-value pedal cycles left in a medium-risk area like a local town center. It is rated against an enhanced tool list. Pedal Cycle Bronze is described as a good deterrent that offers a good level of resistance against the opportunistic thief, suitable for leaving a pedal cycle for a short time in a low-risk area like a cafe or shop. Bronze-rated locks are rated against a short attack using a single, easily concealed hand tool.
Many insurance companies state that a Sold Secure rated lock must be used, and providers will often specify the grade they require. Sold Secure recommends checking your policy before making a purchase. If you own an e-bike, the organization suggests using a Powered Cycle rated product; Pedal Cycle Diamond is equivalent to Powered Cycle Gold because both are rated using the same tools, attack methods, and time limits. For more on securing higher-value bikes, see e-bike rider gear.
How to lock a bike: the frame, the wheels, and what you lock to
The DOJ guide emphasizes that cyclists should lock a bicycle’s wheels and frame to appropriate parking furniture. It recommends using two locks of different types because this defends the secured bicycle against multiple perpetrator techniques. For example, if a cyclist uses a D lock and a chain, a thief would need different tools to defeat each one.
The guide describes several generic lock types. A D or U lock is a D- or U-shaped steel bar that is closed at one end, with a removable section that a key can lock. An armored cable lock has a steel cable core covered with a series of rotating metal tube sections to protect the cable against cutting, and usually has an integrated locking device. The guide notes that armored cables can be very robust, though the lock’s strength depends on materials and quality. Poor-quality chain locks are vulnerable to cutting with bolt croppers and pneumatic cutting tools.
What you lock to also shapes how secure the result is. The DOJ guide explains that the design of the common Sheffield stand does not encourage a cyclist with only one lock to secure the frame and both wheels. An alternative, the M stand, removes the opportunity to lock only the crossbar and forces the user to apply a more effective locking practice, such as securing both the wheels and frame. A study cited in the guide found that locking practices were significantly better for new prototype stands designed to promote secure locking compared with Sheffield stands. Cyclists were more likely to lock the frame and both wheels. The parking environment can influence behavior in a way that increases security, the guide notes.
Flyparking, or locking cycles to trees or street furniture, is common and can contribute to theft because flyparked bicycles are generally less secure than those locked to purpose-built stands, according to the DOJ guide. For home storage, our article on home bike storage security covers garages, sheds, and apartment solutions.
Comparison: lock types in the DOJ guide
| Lock type | Key characteristic (per DOJ guide) | Primary vulnerability noted |
|---|---|---|
| D or U lock | D- or U-shaped steel bar, closed at one end, removable key-locked section | Strength depends on materials and quality; the guide favors pairing two lock types |
| Armored cable lock | Steel cable core covered with rotating metal tube sections, usually integrated lock | Cutting with bolt croppers and pneumatic cutting tools |
| Chain and padlock | Chain with separate padlock; strength depends on materials and quality | Poor-quality chains vulnerable to bolt croppers and pneumatic cutting tools |
The DOJ guide refers to a robust lock as one that can withstand an attack lasting 3 minutes or more by a thief using readily available hand tools. Some robust locks are sold with insurance cover for the bicycle they secure, and the user must register the bike for the insurance to be valid. For a deeper comparison of the three main lock styles, read U-lock vs chain lock vs folding lock.
Registration and what to do after a theft
The DOJ guide states that most cyclists do not know their bicycle serial number, nor can they provide legal evidence of bicycle ownership such as a purchase receipt. As a result, police cannot return many recovered bikes to their owners. Bicycle registration schemes could reduce cycle theft by making it easier to identify stolen bikes and their rightful owners, and may deter thieves by making registered bikes harder to dispose of.
Bike Index, a bicycle registry, outlines steps to take once a bike is stolen. The first and most critical step is to have the serial number recorded. Bike Index advises finding the serial number, usually located on the bottom bracket though sometimes on the head tube, rear dropout, or elsewhere, and registering the bike before a theft occurs. Once you have the number, register the bike with Bike Index, take photos, and keep any other documentation such as a receipt.
If a theft happens, Bike Index recommends filing a police report with the serial number, make, model, and photos. Include any video footage or information about surveillance cameras in the area. Next, register the theft at Bike Index and any local registries. Bike Index notes that it uses an open-data API that can be pulled into any website, so more city registries and police departments are pooling their data there.
Bike Index also suggests spreading the word through social networks, setting up Google alerts with information matching the bike, scouring Craigslist and visiting flea markets, and checking online marketplace apps such as OfferUp and LetGo. If you find your bike listed, contact police rather than confronting a seller yourself. Joining a local bike recovery Facebook group can help; Bike Index points to one group in Edmonton, Canada, that helped return more than 400 bicycles to their rightful owners in a single year.
After a theft, Bike Index recommends investing in better security. It notes that no lock can buy 100-percent certainty, but the best locks give you time. Presenting enough challenges to a crook with a bolt cutter means they will likely seek out easier targets. For commuters building a full setup, our commuter cycling gear article covers locks, lights, and other daily essentials.
Frequently asked questions
Does a higher Sold Secure rating mean my bike cannot be stolen?
No. Sold Secure states that each rating indicates how well a product resists specific threat levels and attack methods, and a rating is a measure of resistance, not a promise. The organization does not claim that any lock makes a bike theft-proof. The DOJ guide notes that observing more-secure locking practices should reduce opportunistic crime, and Bike Index says no lock can buy 100-percent certainty, though the best locks give you time. A higher rating buys more time and resistance, not certainty.
Why should I use two locks instead of one stronger lock?
The DOJ guide recommends using two locks of different types because this defends the secured bicycle against multiple perpetrator techniques. A thief equipped to defeat a U-lock may not be carrying the tools needed to cut through a quality chain at the same time, forcing them to spend more time or move on to an easier target.
What should I do if my bike is locked in a public rack and I notice a damaged lock nearby?
The DOJ guide lists abandoned bicycles (the “broken bike effect”) among the issues police and property managers should look at when tackling bike theft. If you see abandoned bikes or damaged locks at a rack you use, report them to the property owner or local authorities, and make sure your own frame and both wheels are locked to a solid stand.
For more on choosing and using bike security gear, visit our bike locks category page.
