Bike Locks & Anti-Theft

A $30 cable lock is security theater. It looks like protection, it clicks shut with a reassuring weight, and a thief with $10 hand snips is through it in the time it takes you to order a coffee. That is the uncomfortable truth this hub is built around: most of what gets sold as a “bike lock” is designed to reassure the buyer, not to stop the person who actually wants the bike. The good news is that real security isn’t complicated and doesn’t have to cost a fortune — it just has to match the bike you’re protecting and the place you’re leaving it.

Three things decide whether a lock slows a thief down: what it’s made of, how it’s attacked, and how long the thief is willing to stand there working. Resistance comes down to the diameter and hardness of the shackle or chain links, the quality of the locking cylinder (a cheap cylinder can be picked or shimmed in seconds), and how little room the lock leaves for a tool. Thieves, meanwhile, carry a predictable kit: bolt cutters for thin shackles and cables, a bottle jack or crowbar for the empty space inside a roomy U-lock, a hacksaw for soft metal, and — at the top end — a cordless angle grinder that will eventually cut through anything. No lock is uncuttable. A good lock’s entire job is to make your bike take longer, look harder, and carry more risk than the bike parked next to it.

Sold Secure: the rating that cuts through the marketing

Every brand grades its own locks on its own scale — Kryptonite’s 1-to-10, ABUS’s 1-to-15 — and those numbers only mean something within a single brand. The independent yardstick worth knowing is Sold Secure, a UK testing house whose ratings are cited across the industry and asked for by insurers. It grades locks in four tiers, each tied to a defined set of attack tools:

• Bronze— resists opportunist attacks with basic hand tools. A deterrent for the lowest-risk parking, nothing more.
• Silver— a meaningful step up, holding out against a wider set of hand tools. Treat it as the floor for a bike you’d be genuinely sad to lose.
• Gold— the sensible default for a valued bike or a city e-bike: resistant to a serious toolkit, and the tier most insurers want to see.
• Diamond— the top tier, and the only one whose test includes an angle grinder. If you leave an expensive e-bike outdoors in a high-theft area, this is the tier to look for. Whether it’s worth the weight and cost is a real question — we work through it in are angle-grinder-proof locks worth it.

U-lock, chain or folding — which shape to buy

Form factor is the next decision, and each shape trades security against convenience differently. A U-lockis the workhorse: the best strength-to-weight of any type, because a short hardened shackle is hard to attack and leaves little room for leverage — see the best U-locks for commuting. A chaintrades weight for reach and flexibility, wrapping around fat posts and racks a rigid U can’t reach; the heavy hardened ones are the top choice for an e-bike left out, covered in the best chain locks. A folding locksplits the difference — more reach than a U, far more security than a cable, folding flat into a frame holster — and the good ones are in the best folding locks. Cables belong in exactly one role: a secondary lock to loop a front wheel, never your primary security.

Match the lock to the bike and the risk, not the price

A useful rule of thumb is to spend roughly 10–20% of a bike’s value on locking it, then adjust for where and how long it sits. A bike parked outside a train station all day in a dense city needs far more lock than one you bring inside your office. E-bikes push you toward the top of that range no matter what: they’re heavy, expensive and easy to resell, which makes them the most-targeted bikes on the street — a hardened U-lock or chain rated Gold or better is the floor, and the best locks for e-bikes spell out which ones actually fit.

The mistake almost everyone makes

The most common error isn’t buying a cheap lock — it’s buying a good lock and using it badly. A Gold-rated U-lock does nothing if it’s around the front wheel only, or clipped to a signpost a thief can lift the bike over, or left with so much empty space inside that a jack fits in the gap. Technique is half your security, and it’s free: our guide to how to lock your bike properly and the layered plan in how to prevent bike theft cover the frame-and-wheel method, what to lock to, and the registration and habits that get bikes recovered. Start with the roundups below to pick the lock, then read those two to use it right.