A good lock slows a thief down. A bicycle alarm draws attention to them. Most bike thefts happen fast and quietly, so a sudden 110 to 120 dB siren is often enough to make someone walk away before the lock is even cut.
We compared the most popular bicycle alarms on Amazon by siren volume, sensitivity settings, remote range, power source and how securely they mount. These 7 offer the best mix of reliability and value.
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Best Bicycle Alarms at a Glance
- Best Overall Bicycle Alarm: WSDCAM 113dB Wireless Bike Alarm
- Best Two-Way Alarm: WSDCAM Two-Way Bike Alarm 120dB
- Best Rechargeable Alarm: WSDCAM USB Rechargeable Bike Alarm (110dB)
- Best Seatpost-Mounted Alarm: Cruxer 110dB Bike Alarm with Seatpost Bracket
- Most Versatile Alarm: Fosmon 113dB Bike Alarm with Remote
- Loudest Single Alarm: ROCKBROS 115dB Bike Alarm with Remote
- Best Alarm With Tracking: Knog Scout Bike Alarm and Finder
Bicycle Alarm Comparison
| Product | Best for | Siren | Power and remote | |
|---|---|---|---|---|
| WSDCAM 113dB Wireless Bike Alarm | Best Overall Bicycle Alarm | 113 dB siren | Battery, remote to 66 ft | View |
| WSDCAM Two-Way Bike Alarm 120dB | Best Two-Way Alarm | 120 dB, two-way alerts | USB-C, remote to 1,148 ft | View |
| WSDCAM USB Rechargeable Bike Alarm (110dB) | Best Rechargeable Alarm | 110 dB siren | USB rechargeable, remote to 260 ft | View |
| Cruxer 110dB Bike Alarm with Seatpost Bracket | Best Seatpost-Mounted Alarm | 110 dB, 3D sensor | USB-C, seatpost mount | View |
| Fosmon 113dB Bike Alarm with Remote | Most Versatile Alarm | 113 dB + SOS | Battery, IP65 | View |
| ROCKBROS 115dB Bike Alarm with Remote | Loudest Single Alarm | Up to 115 dB | 3 volume levels | View |
| Knog Scout Bike Alarm and Finder | Best Alarm With Tracking | Alarm + Apple Find My | Rechargeable | View |
The 7 Best Bicycle Alarms
1. WSDCAM 113dB Wireless Bike Alarm
1The original WSDCAM alarm is the most reviewed bike alarm on Amazon, with more than 18,000 ratings. It offers 7 sensitivity levels, 3 volume levels, IP55 water resistance and a remote with a vehicle-finder chirp.
Pros & Cons
What we like
- Huge owner base
- 7 sensitivity levels
- Vehicle search function
Watch out for
- Uses replaceable batteries
- 66 ft remote range is modest
Key Specs
- Siren: up to 113 dB
- Sensitivity: 7 levels
- Water resistance: IP55
- Remote range: up to 66 ft
2Unlike one-way alarms, this WSDCAM model alerts both the bike and the remote in your pocket, with a range of roughly 984 to 1,148 ft. Both units charge by USB-C.
Pros & Cons
What we like
- Remote alerts you too
- Very long range
- 120 dB siren
Watch out for
- Newer model, fewer reviews
- Two devices to charge
Key Specs
- Siren: up to 120 dB
- Range: up to 1,148 ft
- Charging: USB-C (alarm and remote)
3. WSDCAM USB Rechargeable Bike Alarm (110dB)
3This rechargeable WSDCAM alarm comes with a bracket, cable ties and tape for three mounting options, and an upgraded remote that reaches up to 260 ft.
Pros & Cons
What we like
- Long remote range
- Three mounting methods
- Built-in rechargeable battery
Watch out for
- Slightly quieter at 110 dB
- Bracket is visible
Key Specs
- Siren: up to 110 dB
- Remote range: up to 260 ft
- Mounting: bracket, ties or tape
4. Cruxer 110dB Bike Alarm with Seatpost Bracket
4Cruxer uses a 3D displacement sensor, 7 sensitivity settings and a seatpost bracket that keeps the alarm tidy and harder to reach. It charges over USB-C.
Pros & Cons
What we like
- Seatpost bracket included
- 3D motion sensor
- USB-C charging
Watch out for
- 110 dB is a bit quieter
- Bracket fits round posts best
Key Specs
- Siren: up to 110 dB
- Sensor: 3D displacement
- Mount: seatpost bracket, strap or tape
5Fosmon pairs a 113 dB vibration alarm with an SOS button on the remote and IP65 weather resistance. More than 6,700 owners have reviewed it, and it doubles as a luggage, fence or trailer alarm.
Pros & Cons
What we like
- IP65 rating
- SOS panic button
- Multi-purpose
Watch out for
- Battery powered
- Remote is small and easy to misplace
Key Specs
- Siren: up to 113 dB
- Water resistance: IP65
- Extra: SOS mode
6ROCKBROS offers three volume ranges up to 115 dB and three sensitivity settings in a waterproof ABS shell from a well-known cycling accessory brand.
Pros & Cons
What we like
- Loud 115 dB top setting
- Established cycling brand
- Waterproof shell
Watch out for
- Only 3 sensitivity levels
- Fewer reviews
Key Specs
- Siren: 83-85, 105-108 or 110-115 dB
- Sensitivity: 3 levels
7Scout combines a motion alarm with Apple Find My tracking. It arms automatically from your iPhone and hides under a bottle cage, so a thief may not know it is there.
Pros & Cons
What we like
- Alarm and tracker in one
- Hides under bottle cage
- Arms from iPhone
Watch out for
- iPhone only for Find My
- Mixed owner feedback
Key Specs
- Tracking: Apple Find My
- Mount: under bottle cage
- Alerts: siren plus phone
How We Chose
We compared bicycle alarms by siren volume, sensitivity range, remote range, power source, weather resistance and owner feedback. Weighting: deterrence and reliability (35%), ease of use (25%), owner feedback (25%) and value (15%). We did not receive free products, and we do not claim hands-on testing. TOR Scores combine published specs, verified owner feedback and overall value.
How a Bicycle Alarm Works
Most bike alarms use a vibration or motion sensor. When armed, any shake, push or tilt above the chosen sensitivity triggers a short warning chirp and then a full siren if the movement continues. Some models, like the WSDCAM two-way alarm, also alert the remote in your pocket, and trackers such as Knog Scout send a notification to your phone.
How to Choose a Bicycle Alarm
Siren volume
Look for at least 110 dB. Alarms around 113 to 120 dB are loud enough to draw attention on a busy street.
Sensitivity settings
Seven levels let you avoid false alarms from wind or passing trucks while still catching someone handling the bike.
Power source
Rechargeable alarms save buying batteries but need charging every few weeks. Battery models last longer between changes but need spares.
Remote range
Standard remotes reach about 66 ft. Upgraded remotes reach 260 ft or more, and two-way models alert you from over 900 ft away.
Mounting
Brackets and seatpost mounts are harder to remove than tape. Hide the alarm under the saddle or behind the seat tube when possible.
Weather resistance
Choose IP55 or better if your bike lives outside.
Alarm Plus Lock: The Best Combination
An alarm is a deterrent, not a lock. Always use a solid U-lock or folding lock through the frame. Add a hidden tracker if you want a chance of recovery after a theft.
Tips to Avoid False Alarms
- Start on a middle sensitivity setting and adjust after a few days.
- Mount the alarm firmly so it does not rattle.
- Disarm before moving the bike or loading it on a car rack.
More bike security guides: best bike alarm, bicycle alarms with remote and best bike alarm locks.
Sources and further reading: NHTSA: bicycle safety, CPSC: e-bike and micromobility safety and NFPA: smoke alarms. Product specs come from brand listings on Amazon.
Frequently Asked Questions
What is the best bicycle alarm?
The WSDCAM 113dB Wireless Bike Alarm is our top pick thanks to its loud siren, 7 sensitivity levels and more than 18,000 owner ratings.
How loud should a bike alarm be?
At least 110 dB. Most good alarms reach 113 to 120 dB.
Do bike alarms stop theft?
They deter many thieves by drawing attention, but should always be paired with a strong lock.
Are rechargeable bike alarms better?
They save on batteries and often add features, but you must remember to charge them.
Final Verdict
The WSDCAM 113dB Wireless Bike Alarm is the best bicycle alarm for most riders. Choose the WSDCAM Two-Way model if you want alerts in your pocket, the rechargeable WSDCAM 110dB for long remote range, or Knog Scout for alarm plus tracking.
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