AlterLock CycleGuardService


All three road bike concerns are covered!

AlterLock is a bike security service for sports bikes. Keep an eye on your bike with a vibration detection alarm and smartphone notification. In the unlikely event of a theft, GPS tracking helps you find it. It's a new way to live your cycling life with peace of mind.


Bought a new road bike?
Worried if even the most robust locks will be enough to protect it?


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


Afraid to take your eyes off your bike for even a moment?
Ideal for cycling trips.

Main features

Monitor Your Bike with Lock Mode

Go into lock mode with a simple control in the smartphone app, and AlterLock will protect your bike with a loud alarm and GPS system. The long-life battery can last up to two months.ReadMoreYou can control up to three devices from the smartphone app. Locking and unlocking, alarms, and vibration detection levels are also set from the app. If you have an iPhone or any Android model that supports automatic Bluetooth connectivity, you can lock and unlock it with the press of a button on the AlterLock itself, without having to open the app. You can take a break from your car and start driving immediately without the hassle of taking off your gloves or taking out your phone.

Alarms & Notifications

When AlterLock detects your bike vibrating while in lock mode, it will sound an alarm and send a notification to your phone. If your bike is moved, a loud alarm will also deter theft.ReadMoreAlarms are highly effective in deterring theft, but you don't have to worry about the embarrassment of accidentally setting off a loud alarm. The initial vibration detection can be set to sound a relatively quiet warning tone. In case of theft, additional vibrations can be added to the alarm to intimidate the perpetrator with a loud alarm. The smartphone has its own notification sound, so you can run to your car without missing it.

Vibration Detection for Multiple Scenarios

Equipped with AlterLock's proprietary vibration detection algorithm. It detects behaviour in the event of theft with settings optimized for multiple situations, from being fixed in a bicycle parking lot to road bikes swaying on bike racks.ReadMoreThe vibration detection mechanism has evolved dramatically in the second generation. By analyzing the shaking and impacts that are likely to occur in different situations, we have succeeded in reducing the number of false alarms caused by shaking and impacts in a cycle rack, for example. In an entirely stationary environment, the system can also be set to react to even the slightest vibration, which can deter theft or tampering with items such as lights.

GPS & WiFi Tracking

In the unlikely event that your bike is stolen, AlterLock tracks it once a minute to determine its final location. If it is moved indoors where there is no GPS signal, the device uses WiFi signals to determine its approximate location.ReadMoreWhat sets AlterLock apart from many other tracking devices is its ability to track your location independently. By employing a highly accurate GPS module and Sigfox communication, the device transmits location information even from hundreds of kilometers away, unlike Bluetooth, which has a maximum range of about 100 meters. The second generation also uses WiFi signals for positioning, increasing the possibility of determining your location even indoors, where there is no GPS signal. It can also provide clues in cases where the vehicle is abandoned or when the police search for it.

Smart Design

Designed with aerodynamics in mind, it can be fitted to the bottle holder pedestal on most sports bikes. It can be discreetly installed into your existing bottle holder without compromising the frame's aesthetics.ReadMoreDo not interfere with the design of the frame. Does not compromise the aerodynamics of the vehicle. It must be lightweight. The AlterLock fits into the downtube width of most road bikes. The curve along the bottle cage ensures that aerodynamics are not compromised. You can feel the lightness in your hands.

Why AlterLock?

Alarm deters thieves

When AlterLock detects a vibration, its alarm sounds, deterring theft and tampering.

Peace of mind with smartphone notifications

When AlterLock detects a vibration, it notifies your phone, so you know to check your bike.

Monitor via Bluetooth

While within Bluetooth range, you'll know your bike is nearby.

Advanced tracking capabilities

AlterLock uses both a GPS and WiFi sensor to calculate its location accurately.

Fine Controls

You can adjust AlterLock's vibration detection level, alarm volume, alarm duration, and turn the alarm on/off.

Small, Lightweight, and Inconspicuous

AlterLock is small, lightweight, and fits discreetly between your sports bike's frame and bottle holder.


Prevents theft and tampering.

Bike: De Rosa Protos, etc.

After having my Pinarello Dogma stolen, I started using AlterLock to prevent theft and tampering. Awareness is the key to prevention. I have installed AlterLock on all my bikes.

I was so relieved my bike was saved!

Luka Pyon
Bike: Merida Reacto 8000-E

I saw someone checking out my road bike, but I was too far away. He pulled a tool out of his pocket and broke the key. However, AlterLock detected the vibration and sounded its alarm, scaring him off.

It's great to have security and peace of mind.

Bike: Specialized Venge Pro

I bought it after hearing the buzz about it. I used to have a standard wire lock and was worried about leaving it while shopping at the convenience store. With AlterLock's excellent security, I have peace of mind. It's rock-solid—no doubt about it!

Easy Installation


Install the app


Subscribe to Bicycle Guard Service


Register your bike and device in the app


Attach the device

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
Download on the AppStore GET IT ON Google Play

※1. Compatible with BLE-supported Android 5.0 and above and iOS 11 and above.
※2. View a list of verified compatible smartphones.

Most common criminal tactics and theft locations you need to know

Easily-targeted bicycle parking situations

Although most people keep their bikes indoors at home, many bikes are stolen from underneath eaves or apartment building bicycle lots.

Places prone to theft and time away from the bike.

The risk of bicycle theft increases the longer you park your bicycle in a bicycle parking lot at home or in an apartment complex, at a station, work, school, etc. You can reduce the risk of theft by not leaving your bicycle in a parking lot for long periods.

Common Misconceptions

"My road bike isn't an expensive model. It'll be fine."

Some criminals target expensive road bikes, but many don't know much about the value. Many criminals ride around on bikes because they look cool or expensive and then discard them.

"Anti-theft devices are only worthwhile if your bike is targeted by professional thieves."

According to statistics from the Tokyo Metropolitan Police Department, more than half of all crimes are committed by young people. As these crimes are easy to execute, many are committed alone, so a burglar alarm can be a great deterrent.

"Stolen road bikes are never returned."

A survey of actual bicycle theft found that 21% of stolen bicycles were found within six months. With the growing use of security registration and GPS devices, the detection rate is expected to rise.


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

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.

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.

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.

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 sensitivity of the alarm sound and vibration detection?

Device Specifications

Size159mm long x 38mm wide x 9mm thick
Battery Lithium polymer
Lithium polymerUSB Type-C
(charging cable not included)
TemperatureOperating Temperature -20~60℃
Chargeable Temperature 0~45℃
Uptime Up to 1.5 months
(varies according to usage)
Communications Bluetooth Low Energy / Sigfox
Location TrackinGPS (GNSS) / WiFi
Water/Dustproof IP66
AccessoriesStart Guide, 2 mounting bolts
Options2 anti-theft bolts, special tools
*Only sold in combination with the device

Communication Areas

AlterLock transmits data via Sigfox (the LPWA communication standard) when outside of Bluetooth range. LPWA makes it possible for the device to communicate on its own with low power consumption and low cost.
Since Sigfox has different communication bands in different regions, Alterlock comes in several editions.

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

For more information on the area, please see the process of getting started.

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