U lock, chain or cable: choosing a bike lock

Three common lock types suit different needs. This guide summarises the points that matter when you choose.

U locks

The U lock is the most popular type with cyclists, and the one that offers the most protection.

• Look for tool hardened steel. Standard steel can be broken with a saw, hammer or crowbar.
• Large models can secure both wheels and the frame, while small models protect only one wheel.
• Choose a size with little empty space around the frame and wheels, so there is no room to wedge in a crowbar or car jack.
• The trade off is bulk: U locks take up the most space.

Chain locks

Chain locks are strong enough for high crime areas and resist common theft tools. They offer more mobility than cable locks and are less bulky than a U lock.

• They are heavier than cable locks.
• Choose a chain with a durable protective cover to avoid scratching the frame.

Cable locks

Cable locks are the lightest option, best suited to short stays in areas with low crime.

• Standard bolt cutters can cut cables, so a cable offers deterrence rather than strong protection.
• Choose a cable with a built in lock rather than an external padlock.
• Make the cable long enough to wrap through both wheels and the fixed object.
• Pairing a cable with a U lock covers removable parts such as the seat.

Which suits you?

• Daily parking in busy places: a U lock, sized snugly, as your main lock.
• Short stops: a chain or cable for convenience.
• Maximum flexibility: a U lock for the frame plus a cable for the wheels.

Security ratings

Where a lock has no independent security rating published, its product page says so, so you can choose with that in mind.