Best Bike Locks

U-locks (D-locks) are the baseline standard for commuter security — hardened steel shackles resist bolt cutters and are difficult to pry. A quality U-lock is the single most important lock in your setup; the ROCKBROS Heavy Duty U-Lock, for example, pairs a 25mm hardened-steel shackle with a carbon-steel body and a silicone coating that keeps the shackle from scratching your frame.

Chain locks with a hardened-steel chain and a separate lock body offer similar security to a U-lock with more flexibility to lock around awkward frame shapes or through both wheels, at the cost of more weight to carry.

Folding locks (articulated steel bars) pack more compactly than U-locks while offering comparable security from quality brands — a good middle ground for riders who want a smaller carry footprint.

Keyless smart locks are a newer category worth knowing about: the ROCKBROS NFC Smart U-Lock unlocks with a tap from your phone or an included NFC card instead of a physical key. Genuinely convenient if you're tired of digging for keys one-handed, but you're trading that for a battery to keep charged (rated around 1,500 unlocks per charge) and a higher price than an equivalent keyed U-lock.

Cable locks are the weakest common option — easily cut with basic tools in seconds. Use a cable lock only as a second, supplementary lock, such as the ROCKBROS 5-Digit Combination Lock for securing a wheel, never as your only lock in an unattended public location.

Thieves who carry bolt cutters or angle grinders are usually equipped for one lock type, not two. Locking with a U-lock through the frame and rear wheel, plus a cheaper cable lock through the front wheel (if it’s quick-release), covers both wheels and the frame without needing to carry two expensive locks — the Heavy Duty U-Lock above is sold with its own 4ft security cable for exactly this pairing, so you don't have to shop for the second lock separately.

Where and how you lock matters as much as what you lock with: always lock to a fixed, immovable object, keep the lock shackle as full as possible (less room to insert a pry tool), and position the keyhole facing down to make it harder to pick or pour debris into.

Security and weight are in direct tension — the most theft-resistant locks are also the heaviest to carry daily. If your bike is parked in a high-theft area for hours (a train station, a busy downtown street) for most of the day, it’s worth carrying a heavier, more secure lock. If you’re mostly parking briefly in lower-risk spots, a lighter folding or compact U-lock is a reasonable tradeoff.

No lock is unbeatable given enough time and the right tools, so it's worth having a plan for the case where locking and technique aren't enough. A hidden Apple AirTag — the ROCKBROS Hidden AirTag Bike Bell conceals one inside a working bell — lets you track a stolen bike through Apple's Find My network instead of losing it entirely. Pair that with registering your bike's serial number, which is free and takes about five minutes, and gives you something concrete to hand a shop or police department if the bike does turn up.