Alterlock Anti-Theft GPS Monitoring Machine Overview

Bike theft is unfortunately a very real reality, whether it’s outside the cafe, locked in the street, or in your garage. In many cases, the best bike locks will ensure your bike is still there when you return. That said, if a thief wants your bike badly enough, even the biggest D-lock won’t stop them.

Alterlock is an alternative approach to bike safety that offers an alarm and long range GPS tracking and communication feature that allows you to track down and restore your bike when the unthinkable happens.

But how well does it compare against the best bike GPS trackers? Is it a game changer or should you still get the best bike insurance you can find to be sure?

A side view of the Alterlock on a bike

Alterlock fits with the bottle cage mounts on the bike (Photo credit: Graham Cottingham)


Installation is as easy as attaching a bottle cage and, unless you have a very unconventional frame, fits over road, gravel and mountain bikes. Since the Alterlock adds 9mm of depth, you can’t use your standard screws, but Alterlock includes some extra long screws with 3mm Allen wrench heads. Once assembled, it’s safe and out of the way. Another benefit of being under the bottle cage is that it’s protected from splashing water on the front wheel, although the Alterlock is IP66 (waterproof) certified so you don’t have to worry about riding in any weather.

For those concerned about aerodynamics, Alterlock says the device only adds a drag coefficient of +0.00062 at 40 km / h. If weight is an issue for you, Alterlock weighs just 50g, making it a lighter option than even the best lightweight bike locks.

The system process in use has three phases. Once locked, the Alterlock will make a warning sound and send a notification to your phone when it detects vibrations. If the vibrations are still detected, the 95dB alarm will be activated and the Alterlock will begin transmitting its location. Subsequent vibrations will not reactivate the alarm, but the Alterlock will quietly notify you of its location after each additional vibration so that you can track its last location.

Tracking is done via GPS and WiFi to try to cover as many bases as possible. GPS provides accurate location services and when the bike is stowed in it the Alterlock uses Wi-Fi to determine its location. While Bluetooth is used to connect to your phone, once the Alterlock is out of range, it switches to Sigfox communication, which can send location information over long distances with low power consumption. The lithium polymer battery is charged via a USB-C cable and has a lifespan of 1.5 months, so you have plenty of time to locate your bike.

The operation of the app itself is relatively self-explanatory. It’s divided into two main tabs: one for controlling and tracking the Alterlock device, and another for bike information and maintenance data. Keeping track of maintenance and component data is a nice touch, and the amount of data that can be documented is pretty extensive for you to keep track of, from the last time you cleaned your chain to upgraded your handlebars. There is also access to account information and settings.

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The Alterlock device weighs only 50g (Photo credit: Graham Cottingham)Image 2 of 2


At one end is the USB-C charging port and the function button (Photo credit: Graham Cottingham)


While the alarm is sure to scare off some opportunistic thieves, or at least alert you or someone else to intervene, it won’t scare off the brash robbers. This is where the GPS and Sigfox functionality obviously comes into play and allows you to track the bike. However, the effectiveness of this is in the hands of the thief. If you are too annoyed by the alarm sound or are versed in cycling, the thief can simply remove the alarm with a 3 mm Allen key and throw it away as soon as possible. Obviously, the thief will need a multi-tool handy and using the security screws would make this much more difficult (but they come at an additional cost at the time of purchase). If the thief is very tech savvy, they could just press the physical button on the alterlock before setting off on your bike and you might not be the wiser until you come back and find that your bike is missing.

Adjusting the vibration detection sensitivity is a nice touch that should expand the scope of Alterlocks. This means it isn’t limited to protecting your bike while you go to the stores, but also when you plan to use it on the back of the car or van.

GPS accuracy is always location dependent, and if the thief hoards your bike in a building waiting for the heat to pass you will lose the signal. This is where the Alterlock switches to using Wi-Fi networks to determine its location, although this is obviously not as accurate as GPS and is made worse if the thief lives in a densely populated area. It is also unable to distinguish vertical position. So if your bike is in a multi-story building it would also be very difficult to locate.

A perspective of the back quarter of the Alterlock attached to a bike

Alterlock’s relatively small shape should mean it won’t be noticeable when attached to a bike with a water bottle (Photo credit: Graham Cottingham)


If you’re looking for a way to track down your pride and joy, attaching the Alterlock is probably your best bet. The Trifecta approach to location tracking, paired with the battery-saving accelerometer, should hopefully give you enough time and accuracy to organize your local authorities to recover your bike. The shape is also neat and easily fits under the bottle cage without affecting the bike’s performance. The app offers many customization options for functionality and sensitivity as well as the actual setting of the alarm and bike tracking.

Apart from an annoying sounding alarm and the resulting mess of bike shoes on the café floor, nothing stands in the way of an opportunistic bike thief to try his luck. Meanwhile, products like Hiplock’s FX Cable Lock cost just £ 20 (less than the annual subscription needed for Alterlock) and create a tangible barrier that prevents anyone from riding your bike. Keep in mind that Hiplock’s FX lock is easy to sever, but if a bike thief drives around with a set of bolt cutters, they likely won’t be put off by an alarm either.

Would you like to have your bike insured? Compare bike insurance and find the best deal.

Technical data: Alterlock Anti-Theft Tracker

  • Price: £ 114.99 / € 134.99 (£ 3.49 / € 3.99 monthly subscription, £ 34.99 / € 39.99 annually)
  • Weight: 50 g
  • Location detection: GPS, WiFi
  • Service area: Europe
  • Colour: black

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