How to stop your bike being stolen: locks
Bike theft in the UK is largely a solved problem with an unsolved human element. The techniques that work are well known, cheap-ish, and mostly ignored.
The blunt summary: a lock that can be cut in 20 seconds will be cut in 20 seconds. No lock defeats an angle grinder for long. What you can do is make your bike the less attractive target on the rack, and make it harder to sell if it is taken.
What actually gets stolen
Before locks, understand what thieves want:
- Whole bikes from racks and gardens. The most common.
- Wheels and saddles from bikes that are locked by the frame only, or not at all.
- E-bike batteries, which are valuable, removable, and often sold separately.
E-bikes are now a specific target because the battery and motor are worth several hundred pounds on their own, and because e-bikes are expensive and often parked in the same predictable places.
The lock standards that matter
The UK has a recognised testing scheme: Sold Secure. Locks are rated Bronze, Silver, Gold or Diamond, and the rating is what insurers use. If your policy requires a Sold Secure Gold lock, a lock without that rating is not compliant, whatever the shop assistant says.
- Bronze: resists casual attack. Fine for a cheap bike left for minutes in a low-risk area.
- Silver: resists hand tools and basic cutting. The minimum for anything worth more than a few hundred pounds.
- Gold: resists heavy tools, including some power tools, for a meaningful time. The standard insurers ask for on bikes over about £1,000.
- Diamond: the highest rating, for high-value bikes in high-risk areas. Expensive and heavy.
Two locks are much better than one good one. Most thefts use one tool, and a thief equipped for a chain lock may not be equipped for a D-lock. A D-lock through the frame and rear wheel, plus a cable or chain through the front wheel, is a far harder target than either alone.
What the ratings do not tell you
Sold Secure tests against a defined set of attacks for a defined time. It is a good guide, but it is not a guarantee: a cordless angle grinder will defeat most Gold locks given 60 seconds and no interruption. The rating tells you the lock resists a determined attack for long enough to make it not worth it in a public place. It does not make the bike unstealable.
How to lock, which matters more than what you lock with
A Gold lock used badly is worse than a Silver lock used well.
Lock the frame, not just a wheel. The classic mistake is passing the lock through the front wheel and a rack. The thief takes the frame and everything else, leaving the wheel. Pass the lock through the frame triangle and around the rack.
Lock to something immovable and higher than the bike. A thief can lift a bike over a low post. Sheffield stands, railings bolted into the ground, and proper bike racks are good. A signpost that lifts out of the ground is not.
Keep the lock off the ground. A lock resting on the pavement gives the thief a stable surface to attack with a hammer or a grinder. Keep it at waist height or above.
Fill the lock. A D-lock with space inside can be attacked with a jack. Shorter, tighter locks are safer than long ones, which is why a small D-lock is often better than a big one.
Lock in a visible, busy place. Theft is deterred by being seen and by being interrupted. A rack outside a busy shop is safer than a quiet side street, even if the side street feels more secure.
Take removable parts with you. Quick-release wheels, saddles with quick-release clamps, lights, and e-bike batteries. If it comes off easily, it will.
Where the risk actually is
The patterns are consistent across UK crime data:
- Home is the highest-risk location. Most bikes are stolen from gardens, sheds, communal hallways and outside the front door, not from town centres. A shed with a flimsy lock and a visible bike through a window is the single biggest exposure.
- Overnight is the highest-risk time. A bike left in a communal hallway overnight is at more risk than one locked in town for an hour.
- Repeat locations. If a bike is stolen from a rack, another bike locked in the same place is likely to be targeted again.
For home storage: a ground anchor bolted into a wall or floor plus a good chain is the single most effective measure. A shed with a proper lock, no window view of the bike, and the bike chained to the anchor inside is a different proposition from a bike leaning against a wall.
Registration: cheap and effective
BikeRegister (and the older Immobilise) let you register your frame number against your details for free or a few pounds. If the bike is recovered by police, registration is how it gets back to you. Without it, a recovered bike often cannot be matched to an owner and is sold or scrapped.
Frame numbers are stamped on the bottom bracket shell. Photograph yours, register it, and keep the photo. Some insurers discount premiums for registered bikes, and many now require it.
For e-bikes, also record the motor serial number and the battery serial. Those are the parts most likely to be sold on separately.
Trackers
GPS trackers cost £30-150 plus a subscription, and they work: several UK police forces have recovered bikes using them. They are not a substitute for a lock, but they change the odds of getting the bike back.
Two practical points:
- Hide it well. A tracker in an obvious place under the saddle is removed in seconds. Inside the frame, or in a discreet housing, is better.
- Check the subscription. Many trackers need a SIM and a monthly fee, and a tracker that stops working because the subscription lapsed is worse than none.
Apple AirTags are cheap and work, but they are not designed for theft recovery: they notify nearby iPhones, which now includes the thief's. They are a deterrent and a rough locator, not a recovery tool.
Insurance: the part people get wrong
If you insure the bike, read the conditions before you need them. The standard requirements:
- A lock of a specific Sold Secure rating, often Gold for bikes over £1,000.
- The bike locked to a fixed point when left unattended, and often an immovable anchor at home.
- The bike not left unattended overnight outside a secured location, in some policies.
- Theft from a shed covered only if the shed itself was locked, and sometimes only if the bike was also locked to an anchor.
A claim denied because the lock was Silver when the policy required Gold is common and entirely avoidable. Check the schedule, buy the lock the policy specifies, and keep the receipt: insurers ask for proof of the lock.
The honest summary
No lock makes a bike safe. What works, in order of effect:
- Do not leave a valuable bike in a high-risk place overnight, especially a shared hallway or a garden.
- Lock the frame to something immovable, with two locks of different types, at waist height, in a visible place.
- Use a Sold Secure Gold lock if the bike is worth more than £1,000, and check what the insurance requires.
- Register the frame number with BikeRegister, and record the motor and battery serials on an e-bike.
- At home, use a ground anchor in a locked shed, not a bike leaning against a wall.
That is a £60-100 lock, a £20 anchor and ten minutes of registration. It is a fraction of the cost of the bike, and it is the difference between a target and a poor one.