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AlterLock review

11 Jan 2022

A discreet alarm and GPS tracker for added peace of mind, but it isn’t a lock

Cyclist Rating: 
Lightweight and discreet • Instant notification and deterrent alarm • GPS tracking
Not a lock as the name suggests • Ongoing subscription required • Easily removed

Leaving a bike outside is not a relaxing experience. Opportunistic thieves aren't always discouraged by a simple lock, or even a decent lock and a cable. Once a bike is stolen, it is unlikely to be recovered.

With this in mind, the AlterLock provides an added layer of security when you need to leave your bike somewhere you'd rather not. Outside a café, to pop into the supermarket or for when you fancy a cheeky pint.

Let's be clear, the AlterLock isn't a security lock, it is a deterrent with GPS tracking and a bike alarm.

AlterLock: How it works

Weighing a claimed 50g and measuring roughly 159×38×9mm, the AlterLock is a light, inconspicuous anti-theft and GPS tracking device which fits neatly on bottle cage bosses – you can still mount a cage – and operates via a smartphone app.

The device is motion activated with an alarm, so if your bike is moved a noise goes off and you're alerted via the app on your phone.

Once you confirm on the app that your bike has been taken, the GPS tracking system allows you to see where your bike is and hopefully helps you locate it.

Linking the device to your phone is straightforward and done via the app which overall I found very simple to use.

You can link several different bikes and add photographs, specs, serial numbers to help identify your bike should anyone try to take it for themselves.

The device can be activated by pressing a button on it and also via the app. I found it easiest to lock my bike up and then use the swipe option on the app to activate the alarm as well.

The app allows you to adjust the sensitivity of the alarm to three different settings, monitor your bike's location, and pick up any notifications of detected movement. You can also use it to track maintenance history.

The battery lasts around one month and is charged via USB-C, however you'll need to supply your own charging cable.

Of course, there is nothing stopping someone trying to remove the device. However should this happen the AlterLock will sound an alarm to notify the owner.

AlterLock also sells additional anti-theft bolts for those looking for that added security.

Notably, AlterLock says that it’s simple and slim design means it won’t affect a bike's aerodynamics. Without a wind tunnel, this isn't something I was in a position to test, but the device is small and shielded almost entirely by the frame when its mounted to the down tube, so it's hardly going to add significant drag.

AlterLock: Performance

I put the AlterLock on my fixed gear bike which I kept outside in my flat’s open-air bike shed over the Christmas period while I was away visiting family. I was over 100 miles away.

During the week I had several notifications of movement detected, causing me to leap at my phone to check my bike's location.

To my relief, these were all false alarms, for instance when someone had moved my bike while they were getting theirs out.

It was easy to see where my bike was and confirm whether or not it was in the right place.

In this scenario, the AlterLock gave me peace of mind and meant that I rarely worried about my bike.

Of note is that the device is designed specifically for theft prevention which means that GPS location is only activated when the AlterLock device detects movement in Lock mode.

The device is not a GPS tracker which will continuously provide location information. The brand says this is to significantly reduce power consumption and enable long-term tracking. 

So you can't stalk your bike, only when someone tries to nick it.

AlterLock: Price

The Alterlock device costs £114.99 however in order to use the device you need to also pay for the subscription service, which costs £3.49 per month or £34.99 per year.

The ongoing fee is for the Sigfox connectivity service, much like the 'airtime' part of a mobile phone bill compared to the device fee. Without that there's no connectivity between the AlterLock and your mobile phone.

Having to pay for a subscription as well as upfront for the device may not appeal to all.

AlterLock: Bottom line

The AlterLock is a simple to use and unobtrusive device which functions as an alarm and tracker. A bugbear is that it is not a security lock as the name suggests.

Of course, the device doesn't tell you if someone stole your handlebars or wheels but to know the whereabouts of my bike overall was a good feeling.

For anyone looking for added peace of mind when leaving your bike somewhere, this is a useful device which might stop you gulping down your cheeky pint.

£114.99 + subscription

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