Bike alarms, padlocks and ground anchors

Bike alarm: how does it work?

A bike alarm is a unit with a motion sensor, fixed to the frame or built into a lock. The Abus Alarmbox 2.0 analyses movement in three dimensions: a brief knock, such as from a ball, only triggers a short signal, while prolonged tampering sets off a 100 dB alarm for fifteen seconds, after which the unit re-arms. It fits on a round tube and accepts suitable chains or cables to lock the bike.

The Knog Scout combines an 85 dB alarm with location via Apple's Find My network: it screws discreetly under the bottle cage and is controlled from an app. An alarm deters thieves and attracts attention, but offers no mechanical resistance: it always comes in addition to a solid lock.

Bike ground anchor or wall anchor: creating a fixed point at home

A significant share of thefts take place at home, in a garage, a cellar or a yard. An anchor creates the missing fixed point: bolted into a concrete floor or a masonry wall, it takes the shackle of a D-lock or a chain passed through the frame. The Hiplok Ankr Mini fits on a masonry, brick or wooden wall, indoors as well as outdoors; Kryptonite, Axa and Auvray offer anchors for the floor or the wall. Respect the drilling depth and the type of fixing given in the instructions: an anchor is only as strong as the surface it is fixed to.

Padlocks: key, combination or fingerprint

A padlock closes a chain sold on its own, a bike shed or a storage box. Choose a shackle whose diameter is close to that of the chain links and a comparable level of resistance: a weak padlock cancels out the benefit of a thick chain. Abus offers them with a key, with a combination, with a stainless steel shackle for outdoor use, or with a fingerprint reader, which opens without a key or a code; Auvray sells the K-Block to close its chains.

Saddle, wheels, battery, bike rack: the small locks

• Saddle: the Newton anti-theft clamp replaces the seat clamp bolt with a bolt that has a specific head pattern, which can only be undone with its key.
• Wheels with axle nuts: Ixow wheel locks replace the axle nuts, in M9, M10 or 3/8 inch, and can only be removed with the key supplied.
• Battery: Axa supplies a key-operated lock to secure a Shimano battery mounted on a rear rack.
• Bike rack: Thule lockable knobs lock the mounting arms onto the frames of the bikes being carried.
• Helmet and bags: the Abus Combiflex, a retractable steel cable with a combination, threads through a helmet or a bag during a break.

Main bike locks

All these protections come in addition to a main lock: a good-quality D-lock, folding lock or chain lock. To carry that lock on the frame, see the brackets among the lock accessories; the bike locks category presents the whole range.

Back-up protection brands

Kryptonite, an American brand from Massachusetts, complements its D-locks and chains with an Evolution series ground anchor and a Kryptolok disc lock with an alarm.

Abus has given the Alarmbox 2.0 three-dimensional position detection and a 100 dB alarm; the German brand also offers the retractable Combiflex cable and combination or fingerprint padlocks.

Hiplok designed the Ankr Mini, a compact anchor in nylon-coated steel, supplied with two expansion bolts, to take its D-locks and cables.

Axa, a Dutch bike lock specialist, offers an anchor to fix to the wall or the floor and a battery lock for Shimano e-bikes.

Auvray supplies fixed anchor points, including a 65 x 42 mm model with a 14 mm shackle and the Twib, as well as the K-Block padlock.

Knog, an Australian brand from Melbourne, combines in the Scout an 85 dB motion-triggered alarm and location via Apple's network, with tamper-proof screws.

Bike alarms and anchors on sale

Replaced products move to equipment clearance, and the latest arrivals to new arrivals. A garage anchor or an alarm slips easily into a Black Friday order.

Frequently asked questions

Is an alarm enough to protect a bike?

No. It warns and attracts attention, but a thief in a hurry can cut a thin cable despite the noise. Always combine it with a solid main lock, and position it so that it cannot be removed without tools.

How do you fit a bike ground anchor?

Choose a solid concrete floor, drill to the diameter and depth indicated, then tighten the expansion bolts supplied. Place the anchor close to the wall, where the bike is naturally stored, and check that the lock goes through both the anchor and the frame.

How do you stop your saddle being stolen?

Replace the quick-release seat clamp with an anti-theft bolt with a specific head pattern, such as the Newton clamp, and keep the key on your key ring. For a valuable saddle, a cable through the rails adds protection.

Can a tracker find a stolen bike?

A tracker such as the Knog Scout reports its position thanks to the Apple devices that pass nearby: location is not continuous and requires an iPhone. It helps you find a bike that has been moved and then report it to the police, without preventing the theft itself.

Which padlock should you use to close a chain sold on its own?

A padlock whose shackle passes through two links without excessive play, and whose resistance matches that of the chain. A padlock from the same brand as the chain, such as Auvray's K-Block, ensures that the dimensions match.