Bike theft is common, and most bikes are stolen because they were locked in a way that made them easy targets — not because a thief was especially determined or equipped. The good news is that most thieves are opportunistic and will move on if your bike takes meaningful time or effort to steal.
Lock Types
D-locks (U-locks) are the gold standard for urban locking. A quality D-lock from a reputable brand is difficult to cut or break quickly. The key word is quality — cheap D-locks offer little real protection. Look for a well-regarded brand and choose the most secure rating you can afford.
Chain locks can be as secure as D-locks if the chain is made from hardened steel (not just hardened-looking). A thick, high-quality chain combined with a solid padlock provides good security, but the combination is heavy. Avoid thin, light chains — they cut in seconds.
Cable locks are not secure for leaving a bike unattended. They can be cut almost instantly with basic tools and should only be used as a secondary lock to secure a wheel, not as the primary lock.
Folding locks offer a middle ground between D-locks and chains — reasonably compact, reasonably secure, and flexible enough to reach awkward locking points. Quality varies significantly.
The D-Lock Technique
When using a D-lock, the goal is to leave as little empty space inside the lock as possible. A D-lock with lots of empty space is easier to lever open using the frame as a fulcrum. Pass the lock through your frame (the main triangle, not just a wheel) and around the fixed object you’re locking to. The less slack, the better.
If your D-lock has space to spare after locking your frame, use a secondary cable or chain to also secure both wheels.
What to Lock To
This matters as much as the lock itself. A good lock attached to a flimsy sign post or old railing gives a thief an easy route around the lock entirely. Look for immovable, solid infrastructure: dedicated bike stands bolted to the ground, substantial metal railings, or street furniture that isn’t going anywhere.
Never lock to something a thief can simply lift the bike over — a short post or railing that your bike frame can be lifted off is not a secure anchor point.
Using Two Locks
Using two different types of lock is a common recommendation from cycle security experts. A thief with tools to cut a D-lock may not have tools to deal with a heavy chain, and vice versa. It also doubles the time required, which defeats most opportunists.
Where You Park
A well-lit, busy, visible location is better than a quiet side street, even if it’s slightly less convenient. CCTV coverage helps. Thieves prefer to work unobserved. If you park in the same place regularly, vary it occasionally — regular patterns make your bike easier to target.