AlterLock CycleGuardService

AlterLock Cycle Guard Service

Common Challenges for Cyclists

Among all criminal offences, bicycle theft is one of the most common. The number is 180,000 per year in recognition alone. The theft of sports bicycles has been damaged at 83 locked.
(※ 2018 Police Agency Crime Statistics and Our Research)

Bicycle Theft
Aim on the car
Current status of theft and countermeasures

How AlterLock works

01 Auto Guard

When you leave the bike, it will automatically start watching.

02 Alarm & Smartphone Notifications

It detects the vibration of the bicycle and sounds an alarm sound and notifies the smartphone.

03 GPS tracking & communication function

Gps and communication function scan the location of the bike away.

If it is auto guard, the operation of the smartphone is unnecessary.
If there is an abnormality when you are away from the bike, the alarm sounds, and the notification sound to the smartphone is reliable because it stands out.

If the detection sensitivity is changed, it is safe even if it is parked in the cycle rack.
If you turn off the alarm, you can rest assured at the time of wheel line and transportation.

This is the only device that has GPS and communication capabilities even if you don't receive Bluetooth.

Learn more about how it works Click here to purchase a device

Applications (for iOS/Android)

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  • Work with the device to watch over your car.
  • You can get the latest bike news at any time.
  • Maintenance records can be made.
  • Easy access to services that you can find on cycling trails.
  • You can record the security registration number and the vehicle body number, so you can notify them immediately.
  • The exact time and place is recorded.
  • It is also useful when spreading information on social networks.
Get it on the AppStore Get it on Google Play

※1. Compatible with Android 5.0 and iOS 10 or higher smartphones compatible with BLE
※2. On some Android devices, even supported operating systems may not work.
For more information, please check the status ofAlterLock's smartphone operation.

User's Voice

Not only theft, but also mischief can be prevented.

Choku, Tokyo, Man
Bikes: DE ROSA PROTOS, etc.

PinareLLO's DOGMA was stolen at Enomoto Ranch in November 2018. It seems to have been cut even if it had the chain lock. The criminal was arrested, but the bike was not able to ride.
After that, I introduced AlterLock, but I felt that i could prevent not only theft but also mischief.
It is important to prevent you from noticing when something happens. It is installed on all bikes that i own.

Watch the interview

I'm so glad you're safe!

Luke Pyoon, Tokyo, Male, Age

I parked with a wire lock with a fence in front of a bicycle shop in Tokyo. It took about five minutes away from the bike, but there was a person who was looking at my road bike, so i took the tool out of my pocket and broke the key when I looked away.
However, the alter lock that detected the vibration sounded the alarm, so the culprit ran away.

AlterLock is good to be able to do security without worrying.

Michelle, Tokyo, male, age 53
Bike Specialized Venge Pro

If you were looking for a good key on the Internet, you know it's a hot topic, i purchased it. In the past, i was worried about shopping at a convenience store because it was a wire lock.
AlterLock is good to be able to crime without worrying. Things are sure to be! I want it to spread more.
After that, it would be nice if there is a function to share the location information between users.

There is a sense of security when i leave the bicycle.

Mr. H, Chiba Prefecture, male, age 57
Bikes: Cannondale Topstone, etc.

I got to know the alter lock on the Web and thought it would be useful in the event of a theft deterrent and theft.
Fortunately, I have never been indebted to AlterLock, but I feel secure when I leave my bike. When you leave the bicycle, such as meals, i put the smartphone in the place in view and have to be able to see immediately if there is a notification from AlterLock.
AlterLock also has a theft deterrent effect and tracking function at the time of theft, so i think it's more cost-effective than bike vehicle insurance if you think only of theft.

Introductory Comments

Kenji Hashimoto

Since the introduction of AlterLock, you can now rest with confidence without having to park within the direct reach of the area.

See introductory articles

Ryoko Hinata

With the introduction of Alter Rock, we were able to continue to cover the stop-and-drop spots without any consideration.

See introductory articles


A new form of anti-theft measures that are different from the key which read the psychology of the thief side. The sound is a threat from the culprit who doesn't want to stand out! It becomes a considerable security measure.

Watch the introductory video


Device price (suggested retail price)
¥8,241 (tax included 9,065)
Click here to purchase a device

The list of stores handled is here.

* Service usage charges apply separately.

Service charge (tax included)
Monthly Plan Annual Plan
Monthly 396 yen 330 yen
年額3,960円 per month 3,960 yen per year
Free for the first 30 days
Up to three devices available
Flow up to use

Recommended for beginners!
A great set of AlterLock x CROPS is also on sale.


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    Image from the drive side (right)
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    Image from non-drive side (left)
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    Actually installed image (front)
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    Actually installed image (right side)
Learn more about shapes

Developed by cyclists, AlterLock is designed specifically for sports bicycles.

Where are you? 」
It becomes familiar with the frame when seeing from the drivetrain side by thinning it to the limit, and it does not notice the existence.
It doesn't get in the way of Insta shine.
The flange flows backwards and considers air resistance.

"Is the battery in this lightness? 」
The amazing lightness should be able to use the racer who is severe in the weight of the motorcycle on a daily basis.
Even so, you can watch the bike for more than a month on a single charge.

Let's go cycling with AlterLock!

Flow up to use Click here to purchase a device

Device Specifications

Size 150mm length x width 47mm x thickness 8mm
Weight Approx. 60g
Battery Lithium Polymer
Charging Terminal USB (Micro-B)
Up to 1.5
months * Depends on usage.
Communication Method Bluetooth Low Energy / Sigfox
Waterproof/Dust Proof IP66
Accessories 2 bolts for mounting

Frequently Asked Questions

A. It can be attached to a general sports bicycle because it is installed using the mounting pedestal of the bottle cage.
It can be installed with your already bottle cage. If the portable pump or trailer mounting band interferes with the device, it can also be mounted on the down tube side.
A Available in sigfox service areas in Japan. In manual mode, you can receive notifications only within the range of bluetooth connections, even outside sigfox's service delivery area. You can find the service area from this page.

* Notifications may not be received on smartphones in indoors, where radio waves are difficult to reach even in the area, or in environments where radio waves are poor.
A Bluetooth tracker scan once you're away, but AlterLock has a single communication function and GPS, so you can track it anywhere in the communication area.
A. This product is for the purpose of preventing theft, so it cannot be used as a GPS tracker for normal use.
By detecting vibration and then operating the GPS, it is possible to track for a long period of time by reducing power consumption.
A It can be removed when installed with the bolt that comes with the product, but the dealer provides installation services with anti-theft bolts.
A You can adjust the alarm sound on and off and the ringing time between 5 and 120 seconds.
The sensitivity of vibration detection can also be adjusted to the optimum sensitivity in various scenes.
See more

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* AlterLock is a registered trademark of Nextscape Co., Ltd.