Accessories

Security Alarms

Motion alarms and alarm locks to deter tampering.

Alarms occupy the space between locks and trackers. They do not physically stop anyone, but a 110-decibel siren when someone lifts the rear wheel makes an opportunist walk away, and it buys time for a cutting attack to attract attention. For an e-bike parked at a store, a trailhead lot, or an apartment rack, an alarm is a cheap addition that changes a thief's calculation.

There are standalone motion alarms that bolt or strap to the frame and arm with a remote or app, alarm locks that combine a U-lock or chain with a built-in siren that triggers on cutting or movement, and alarms integrated into some e-bikes or aftermarket controllers. Look at loudness in decibels, how the sensitivity is adjusted, and how it is armed. A unit that false-alarms every time the wind rocks the bike gets turned off and becomes useless, so adjustable sensitivity and a short warning chirp before the full siren are features worth paying for.

Mount the alarm where it is hard to reach and pry off, and make sure it is weather-sealed; North Texas rain will kill a cheap unit in a season. Check battery life and whether it uses a replaceable or rechargeable cell. An alarm is one layer: keep the lock as the primary defense, use a tracker for recovery, and think of the alarm as the part that tells everyone nearby something is wrong. Test it once a month so you know it still arms, and replace the battery before it dies rather than after. An alarm you have not heard go off in a year may not go off at all.

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Security Alarms

Knog Scout Bike Alarm & Finder

The Knog Scout does two jobs: it is a motion alarm that screams when the bike is moved, and it is an Apple Find My device so you can locate it like an AirTag. It bolts to the bottle-cage bosses with security screws and is controlled from the Knog app. The alarm is loud enough to make a thief reconsider a quick grab, and it arms and disarms automatically as your phone comes and goes. It is iPhone-only for the Find My function. Rechargeable via USB-C. It works best as a layer on top of a real lock, not a substitute.

Best for: iPhone users who want alarm plus location · Bikes parked briefly outside shops · Tamper deterrence

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How to choose security alarms

Loudness

Aim for 100 decibels or more measured close up. Quiet alarms are easy to ignore. Check whether the alarm keeps sounding, repeats, or stops after a fixed time.

Sensitivity and false alarms

Adjustable sensitivity plus a warning chirp before the full siren reduces false alarms from wind and passersby. Too sensitive gets disabled; too dull is useless.

Arming method

Remote fobs are simple; app-based arming adds alerts to your phone but depends on Bluetooth range. Some arm automatically when the lock closes.

Weather sealing and battery

Look for a real water resistance rating and a battery that lasts months or recharges over USB. An alarm that dies in a month is an alarm you stop maintaining.

Mounting security

Tamper-resistant bolts or placement under a bottle cage or inside the frame triangle keep it from being pried off before it triggers. Some alarm locks solve this by living inside the lock body.

Installation considerations

Mount with security bolts where possible, and route any wiring away from moving parts.
Set sensitivity in the actual parking spot; bikes on a busy rack need a lower setting than a bike alone.

Frequently asked questions

Do bike alarms actually deter thieves?

They deter opportunists and people who would otherwise rummage through bags or try the lock. A determined thief with a grinder may continue, which is why an alarm supports a lock rather than replacing it.

Alarm lock or separate alarm?

Alarm locks are tidy and the alarm is hard to remove. Separate alarms let you choose a higher-rated lock and position the alarm independently. Either works; a rated lock comes first.

Will wind or a passing truck set it off?

It can on high sensitivity. Most alarms have adjustable levels and a warning chirp. Set it so a firm shake triggers it but a bump from another bike does not.

How long does the battery last?

Typically weeks to months for fob-armed units, depending on how often it triggers. Rechargeable USB units are convenient; put a reminder on your calendar either way.