AlterLock Anti-Theft Alarm & GPS Tracking Device

AlterLock is an unobtrusive security device that sounds an alarm if your bike is moved and provides GPS tracking if it is ever stolen. However, the Sigfox network that it uses to provide tracking even when indoors doesn't provide universal coverage, so it can't be described as a failsafe.

AlterLock is 159mm long, 38mm wide (at the widest point), and 9mm deep. The unit itself weighs 48g, and you get two extra-long bottle cage bolts for fitting.

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Speaking of fitting, that's simple. You just push the bolts through the holes in your bottle cage, then through the holes in the AlterLock, and tighten them into your bottle cage mounts. Two minutes tops.

Once in position, the AlterLock is unobtrusive, especially if you have a dark coloured bike and/or bottle cage. It hardly stands out, sitting there securely without rattling. AlterLock says that the device will have virtually no effect on your bike's drag. Aerodynamics is a complicated old business and I couldn't tell you if that claim is correct for any particular bike, but the positioning certainly means that it's sheltered between your frame and water bottle.

The AlterLock works alongside a smartphone app. You download the app (there are iOS and Android versions), pair it to your device, and sort out various settings.

Alarm

The AlterLock sounds an alarm when it detects movement. You can either set up the device to go straight into the full alarm when it detects movement or to give a lower volume warning tone first time... a bit like a dog quietly snarling, hinting that you might want to leave it alone.

The full alarm is certainly loud enough to draw the attention of passers-by and might convince a thief to leave your bike alone and go back to whatever thieves do when they're not trying to nick other people's stuff. It might be enough to deter opportunist theft at a mid-ride coffee stop, for example, if your bike is leaning up against a wall outside.

> Inside the mind of a bike thief – learn how to protect your bike

You can set things like the alarm duration (between 5secs and a minute) and the number of times it goes off (one to three times) via the app. After the set number of times, the AlterLock will stop sounding the alarm and just report its position once it has detected a standstill (see below). You can also turn the alarm off if you like.

As well as sounding the alarm – which might be enough, depending on how close you are to the bike – the AlterLock sends a message to your phone if it is moved: 'Vibration detected! Please check your bike immediately.' This feature has worked really well for us in testing, sending the message through every time it was moved when locked outdoors.

You can alter the detection sensitivity, having the AlterLock react to small vibrations or only to more significant movements, which might be the better option if you leave your bike hanging on a public cycle rack, for example. AlterLock says that the vibration detection mechanism has been developed to avoid false alarms, but there's the slight chance that the alarm will go off and you'll get an alert on your phone if someone innocently adjusts your bike's position while locking up theirs, for example, depending on the setting you're using.

Tracking

The AlterLock's other key feature is its tracking. The idea is that if someone moves your bike, you can find out where it is via the app.

'In the unlikely event that your bike is stolen, AlterLock tracks it once a minute to determine its final location,' says AlterLock. 'If it is moved indoors where there is no GPS signal, the device uses WiFi signals to determine its approximate location.

'What 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 kilometres away, unlike Bluetooth, which has a maximum range of about 100 metres.

'[This] second generation also uses WiFi signals for positioning, increasing the possibility of determining your location even indoors, where there is no GPS signal.'

If you're not familiar with Sigfox, it's 'a global network dedicated to the Internet of Things based on low power, long-range and small data that offers an end-to-end connectivity service'. Essentially, it's a network that allows the transfer of small messages, such as the location of devices like AlterLock.

You can see a map of current coverage here. Of course, if your bike is stolen, you've no control over whether it's taken to an area with coverage or not.

When the AlterLock detects movement, it gets the location information and notifies you via your smartphone. However, the first time it detects vibration after it is locked you'll just get a notification without the location information, the idea being that you can get to where you parked your bike as quickly as possible. The location information will follow soon afterwards; you get it on a zoomable map.

Does it work?

We tried out the AlterLock on many occasions to simulate theft. First, we had someone put a bike with the AlterLock fitted into the back of their car and drive it off to an undisclosed location. Could we find it?

To start with, no. We were told that the bike was somewhere in the English Channel. This was because the system was failing to account for the fact that we were west of the prime meridian. It was saying that the bike was east of the meridian, somewhere near Ostend. Teething troubles. AlterLock soon put this right so it won't be a problem for you.

Once sorted, the bike's locations started to come through to the app correctly, and it was easy enough to locate. You get a map of the position on the app and you can send the location over to Google Maps and use that to navigate. Off we went in pursuit and found it in no time. Okay, the map showed the car on the wrong side of the road, but it was within metres. If you found five vans all lined up next to one another you wouldn't know which one your bike was inside, but the tech would get you there or thereabouts.

We did this a few more times, with the AlterLock in a car a few streets away and a few miles away, and it worked well every time. Of course, the car could be moved again, in which case you'd get an updated location.

Next up, we had someone move the bike to a friend's house. This was more challenging. In a car, the AlterLock could send its location via GPS. In a house, GPS isn't usually possible so the system would be reliant on Sigfox.

We had mixed levels of success here, depending on the location. In the area where I live, once the bike was taken indoors we got nothing.

On the other hand, in the area where Dave lives, we were able to tell where the bike had been taken.

Bear in mind, though, that it might not be totally straightforward every time. Locating the AlterLock in shared premises might be complicated, for instance, and you'll get the same position on the map whether the device is on the ground floor, the first floor, or the 15th floor.

The AlterLock can't be turned off – they're not going to make it that easy for a thief – but couldn't a wrong 'un just remove it from your bike? Although we didn't have them on our review device, the AlterLock does come with anti-theft bolts. A thief could still remove the device if they really wanted to but they might only do that if they realised that it's a tracker rather than just an alarm (as mentioned, the alarm will sound a maximum of three times, it won't just keep going on forever).

I went to a police contact to find out what they'd do if the AlterLock indicated that your stolen bike was located at 52 Festive Road, or wherever. It's not quite as black and white as you might hope.

First, different police forces have different policies. Then there's the fact that different types of trackers have been used on motor vehicles for years and police have frequently turned up at locations as a result of 'ghost signals' – the tracker isn't actually where it's supposed to be – although the AlterLock hasn't ever given us duff information. Police have also been known to arrive at a particular place to find that the tracker has been removed and chucked away there.

The police might go and knock on the door of the premises where you suspect your bike is being stored, but if no one answers or the occupier refuses entry, they'll need a warrant, signed off by a magistrate, to get inside.

The point the police made to me was that yes, a tracker can be very useful, but it's sometimes not simply a question of going where the app tells you and getting your bike back. Real life can be more complicated. That said, if your bike was stolen you'd far rather have tracking info to work with than nothing. All of this applies to any tracker, not just the AlterLock.

Battery life and build

The AlterLock runs on a lithium polymer battery that you recharge via a USB-C connector. It'll last up to two months between charges, depending on the environment and usage conditions, and you get an alert on your phone when it needs topping up.

The AlterLock has an IP66 rating which means it is protected from dust ingress and high-pressure water jets as long as you have the USB charging port protected by the cover provided.

Cost

As well as the initial payment for the AlterLock, after a month-long free trial period you need to pay a subscription fee of £34.99 per year or £3.49 per month (paying monthly would work out at £41.88 per year). The agreement can be cancelled during the trial period, but not for six months after that.

Stu reviewed the Tail It Bike GPS tracking device last year and rated it highly, although he found that it wouldn't fit the complex bend shapes of some road handlebars.

The Tail It Bike GPS doesn't provide an alarm, though. Quite the opposite, it's designed to hide away so that a thief has no idea that it's there, taking an approach that's very different from that of the AlterLock where deterrence is front and centre.

That device was £83.89, so over 25% cheaper than the AlterLock and the subscription is cheaper too.

We recently reported on Vodafone's new Curve Bike Light & GPS Tracker which is £79 with a subscription of between £36 and £48 per year. We reviewed one recently and George said that it 'has the potential to be an impressive piece of hardware, but is let down by a lack of predictability and an app that needs improvement'.

Neither of these devices uses Sigfox.

Then there are Apple AirTags that were released earlier this year. An AirTag sends out a Bluetooth signal that can be detected by nearby devices in Apple's Find My network. These devices send the location of your AirTag to iCloud and you can go to the Find My app and see it on a map.

An AirTag costs £29 and there is no monthly subscription. George tested a four-pack and liked the low-tech system.

Overall

With all this in mind, I'd say AlterLock's main strength is in deterring theft in the first place. If anyone touches your bike the alarm essentially tells them to back off and pick on someone else. It's particularly useful for things like parking at a cafe stop or in any other public place when you're relatively close by. You get the alert on your phone saying that someone is messing with your bike and you can rush to get there as quickly as possible.

If the worst happens and someone does steal your bike, the GPS tracking technology works well in our experience, but the Sigfox network isn't universal. If a thief takes your bike to an area that isn't covered, you're not going to get any information about where it is.

Verdict

Interesting security device that lets you know if your bike is moved and helps you locate it