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  • Regular price ¥19,500

30 days of free service

Customer Reviews

Based on 135 reviews
ま. (Minatomirai, JP)
I have a sense of security.

Setup was easy.
The use of AlterLock in addition to the keylock gives me peace of mind.
The volume could be louder.

匿名 (Hiroshima, JP)
I have the greatest sense of security wearing it.

It would let me know if there is something unusual even if I am out of sight... I think this alone is worth installing. I have installed it in both of the cars I own.
But don't be overconfident, do daily test runs, etc. to check whether the alarm goes off normally? Do you receive notifications on your phone? If the system does not notify you of an abnormality, you should check the status of the system.
I had a problem before where no notifications were sent out, and when I contacted support, they kindly told me how to deal with the problem, which was a relief, but I feel that checks should be carried out to avoid missing something that is not working...

ケ. (Kyoto, JP)
Generally satisfied, but...

I'm generally happy with it, but overall I feel like it could still be improved.
I'm hoping for more features and specs in updates and gen3.
Real-time tracking with updates every second or so.
Battery life more than doubled.
Stable Bluetooth connection range.
Connecting, unlocking and locking with Apple Watch.
Vibration + alarm function at 5m of positional movement.
Other functional improvements are expected.
The last major system of vibration detection has a lot of false positives, and I feel it would be easier to use if a system that recognises by GPS position movement could also be added as a mode.

Thank you for your contribution regarding specific suggestions for improvement!
We will make use of them in future product development.
As for the false positives, we have further improved them in the recent firmware, and we would appreciate it if you could try it out.

Free shipping | 30-day return policy

All three road bike concerns are covered!


  • Worried if even the most robust locks will be enough to protect it?


  • Worried about leaving your bike unattended—even for a short time?


  • Afraid to take your eyes off your bike for even a moment?

Why AlterLock?


Alarm deters thieves


Peace of mind with smartphone notifications


Monitoring via Bluetooth


Advanced tracking capabilities


Fine control


Small, lightweight, and inconspicuous

App Features

  • ・Register your bike's photo, specs, and VIN number
  • ・Toggle the device lock mode
  • ・Device settings (for various situations including vibration detection level, alarm on/off, alarm duration, first alarm sound, number of alarms, regular transmission, etc.)
  • ・Push notifications and audible alarms when the device detects vibration or receives location information
  • ・View location and history while tracking on the map screen
  • ・Tracks maintenance history for safer riding
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Easy Installation


Install the app


Subscribe to the Bicycle Guard Service


Register your bike and device in the app


Attach the device

Device Specifications

Size 159mm long x 38mm wide x 9mm thick
Weight 50g
Battery Lithium polymer
Charging terminal USB Type-C
charging cable not included
Temperature Operating Temperature -20~60℃
Chargeable Temperature 0~45℃
Uptime Up to 1.5 months
*varies according to usage
Communication Bluetooth Low Energy / Sigfox
Location Tracking GPS (GNSS) / Wi-Fi
Water/Dustproof IP66
Accessories Start guide, 2 mounting bolts
Options 2 anti-theft bolts, special tools
*Only sold in sets with the device


Product Price €134.99/£114.99(tax included)
Service Fee £3.49/month,£34.99/year(tax included)
€3.99/month,€39.99/year(tax included)

Communication Areas

AlterLock transmits data via Sigfox (a low-power, wide-area [LPWA] communication system) when beyond Bluetooth range.LPWA allows the AlterLock device to communicate independently of your smartphone with minimal power consumption and at low cost.Since Sigfox uses different communication bands in different regions,Alterlock comes in several versions.

The European version is available in the following countries: Belgium, Croatia, Czech Republic, Denmark, Finland, France, Germany, Hungary, Ireland, Italy, Luxembourg, Netherlands, Portugal, Slovakia, Spain, and United Kingdom.


Can AlterLock be installed on any bike?

It can be attached to a standard sports bike using its bottle holder's base or in conjunction with your existing bottle holder.

What areas can I use this service in?

It can be used within Sigfox's service area (primarily Europe). Outside the service area, all functions will work within the Bluetooth transmission range. You can check the service area from this page.* Even within the service area, notifications may not reach your smartphone indoors where the signal is weak or in an environment with poor reception.

How is AlterLock different from Bluetooth trackers?

Bluetooth trackers are challenging to track once they leave your hands. AlterLock has stand-alone communication and GPS, so you can track your device wherever you go.

Can I check my location anytime?

This product is designed specifically for theft prevention. It cannot be used as a GPS tracker that continuously displays location information. Vibrations made in lock mode activate the GPS to significantly reduce power consumption and enable long-term tracking.

Can the device be removed easily?

If you try to remove the device, AlterLock detects the vibration and sounds an alarm to notify you, so you can rush to your bike. If you're still concerned, an additional anti-theft bolt and special tool are available. Please consider purchasing the device as a set. These items are not sold separately.

Is it possible to adjust the volume of the alarm and the sensitivity of movement detection?

Yes, it is. The movement detection sensitivity can be set to one of three levels.

Proudly engineered in Japan