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(The Gear Loop) - We’ve tested a fair few non-Garmin GPS smartwatches and bike computers here at The Gear Loop and we always reach the same conclusion; it’s good but it’s not a Garmin. The depth of data and user experience of the American behemoth’s devices is unparalleled. 

Garmin still hasn't released the perfect cycling computer (in our humble opinion), but it’s often the most complete package that’s on offer, so when the Karoo 2 from Hammerhead landed on our desk we were intrigued. Could this GPS cycling computer finally topple Garmin from its lofty throne?


It’s certainly got some headline specs to take the fight to its rivals, from the glorious 3.2-inch Dragontrail Glass display and smartphone-esque user interface to the impressive connectivity speeds, could this be the bike computer keen cyclists have been waiting for? We loaded up the bike and hit the road to find out.

Our quick take

The Hammerhead Karoo 2 might not boast the same enormous spread of metrics like some of its competitors, but if you’re looking for a cycling computer that has 95 per cent of the functionality of rivals, crammed inside one of the sleekest and slickest packages we’ve ever tested, it could be the bike computer for you. 

Hammerhead Karoo 2 review: the slickest screen seen on a cycling computer

Hammerhead Karoo 2

4.5 stars - The Gear Loop recommended
  • Beautiful screen
  • Custom Android OS is silky smooth
  • Mapping features are unparalleled
  • Web dashboard makes route management simple
  • Fewer performance metrics
  • Flimsy charging port cover
  • Proprietary mount


In the Loop

Everything you need to know about the Hammerhead Karoo 2 in brief:

  • 3.2 inch Dragontrail Glass display
  • 167 grams including mount
  • 2500mAH battery for 12 hours ride time
  • Quad core CPU with 2GB RAM
  • 32GB onboard storage
  • Smart routing and navigation
  • TrainingPeaks workout integration
  • Strava Live Segments
HammerheadHammerhead Karoo 2 review photo 16

First impressions and set-up

First impressions are strong, the matte black box unfolds to reveal the head unit nestled inside, the mounts and brief instructions live below in their own drawer.

There’s something very Apple about the packaging - everything is very deliberate and considered. You’ll notice we said mounts plural, as the Karoo 2 comes with an out-front mount as well as an adaptor that allows the ubiquitous Garmin mount to be used if you’ve already got a fleet of bikes with plastic dangling from the handlebars. 

The Gear LoopHammerhead Karoo 2 review photo 2

Sliding the head unit onto the mount is a straightforward affair, however we did need to consult the instructions when removing it, as it requires some force to dismount, both twisting and pushing. 

Power up the Karoo 2 and it becomes obvious that this isn’t a knock off Garmin with underpowered internals and a confusing menu system. The slick start up animation offers hints that the Karoo 2 is packing a punch - a quad core processor and two gigabytes of RAM drives a custom Android operating system, meaning the Karoo 2 is essentially a mini smartphone. 

The Android OS ensures inputs proved slick, while the initial setup of the device required data to be entered via keyboard. This would normally strike fear into our hearts, the thought of using a tiny keyboard on a slow and clunky device can incite much rage… but not here. Inputs were accurate and effortless, the keystrokes buttery smooth and it really felt like a phone screen to operate.

The Gear LoopHammerhead Karoo 2 review photo 7

The final part of set-up involved downloading the correct maps for your region. This forms the foundations for some really impressive features that we’ll get into later. 

Maps are installed to the 32GB of internal storage and adding additional maps is as easy as delving into the settings and hitting download on the correct bit of cartography. No faffing about connecting the device to a computer via USB and dropping bootleg copies of maps into folders on the device. 

Connecting the necessary sensors, such as heart rate and power metres to the Karoo 2 is laughably simple too. Choose either ANT+ or Bluetooth and wait for the sensor to appear. 

HammerheadHammerhead Karoo 2 review photo 15

We had no problems with either protocol and it found our sensors within seconds of powering up. If your bike is equipped with SRAM AXS, the Karoo 2 can display the current gear but unfortunately Shimano is no longer supported since SRAM acquired Hammerhead.  

Data and menu screens

Heading out for a ride is a simple as selecting an activity profile. There’s a handful of pre-made settings for indoor and outdoor riding and they can all be customised, with new ones easily added too. 

Customisation is the name of the game with the Karoo 2 and you can add as many data fields as you can manage to the main ride page, which can be swiped between. 

The Gear LoopHammerhead Karoo 2 review photo 8

There aren’t as many training metrics as Garmin offers, so don’t expect to be able to see left and right power balance and your Body Battery, but we think there’s enough for even the majority of riders to pour over post-ride via Hammerhead's online web dashboard. 

The Karoo 2 does, however, include some new environmental metrics, including the climate  impact of your ride. So if you decide to commute to work by bike, the Karoo 2 (in partnership with Suunto) will provide an estimate of the CO2 emissions you’ve saved. It’s an interesting feature that might satisfy a curious rider but beyond that we doubt it’s particularly useful for anyone. 

The standard "homepage" of the Karoo 2 is a map with a selection of simple data fields at the bottom. Some will prefer to have a full page of data but we liked the map and simplified combo, even on routes that we rode regularly. 

HammerheadHammerhead Karoo 2 review photo 13

The party piece of the map is its ability to provide live elevation profiles of the enormous hill you’re riding up, breaking down the elevation and distance left into a graphic that we could still understand having gone full blast up said hill and blurring the vision slightly. 

Long press on a spot on the map and the Karoo 2 can navigate you there using data gleaned from Suunto heatmaps to make sure the route is cycling-friendly and if you do miss a turn, the Karoo 2 will intelligently re-route you rather than beep and flash at you to turn around. 

If you fancy exploring new roads, the Karoo 2 highlights cycling friendly routes with a blue outline, making it easy to quickly select a new area to explore.

The Gear LoopHammerhead Karoo 2 review photo 10

The team at Hammerhead is also committed to releasing fortnightly updates for the Karoo 2, so the features will be continuously evolving and improving over time. 

Performance on the bike

All of the data mentioned above is displayed on a beautifully sharp and vivid Dragontrail glass panel with an acid etched matte finish. It’s got a stupid name but boy does it look good, displaying 16.7 million colours across its 3.2-inch screen and the matte finish means that even in direct sunlight the display is easy to read. 

The touchscreen uses smartphone-esque capacitive technology to make sure every tap and swipe is accurate and smooth. Droplet rejection technology means that if you’re riding in the rain, water droplets won’t cause havoc with the display giving it a mind of its own.

The Gear LoopHammerhead Karoo 2 review photo 9

In the depths of winter, riding with gloves becomes a necessity, and as we know gloves are a touchscreen’s nemesis. Not with the Karoo 2, as four buttons on the chassis mean the majority of operations can be completed without having to use the touchscreen at all. 

Connectivity is hugely impressive too, as the device can download routes from Hammerhead’s online-only portal via Wi-Fi, which means no more faffing about with cables. 

If you’re out and about, the Karoo 2 has a sim card slot hidden under a cap on the back so it doesn’t need to rely on Wi-Fi. Downloading live segments to see real-time comparisons from Strava is simple too, simply star the segment via Strava's app or web dashboard and it’ll appear on the Karoo 2 when you approach the segment on the road or trail. 

HammerheadHammerhead Karoo 2 review photo 17

However, we’re indifferent as to whether we’d prefer an app to manage routes and more. An app would be simpler than having to navigate to a web page, which sometimes didn’t quite scale correctly to our phone screen, but a quick refresh sorted that out. 

On the other hand, it means the dashboard can be accessed from any device with a web connection, so if you’ve forgotten your phone you can still manage routes from other devices and see all of the metric and data from your recent ride.

Battery life and charging

The Karoo 2 packs a 2500mAH battery, which Hammerhead claims is good for 12 hours of riding, and thanks to USB C fast charging, it only takes three hours to fully charge. 

The Gear LoopHammerhead Karoo 2 review photo 11

We’ve found these figures to be fairly accurate. Admittedly, we haven’t logged any 12 hour rides, but the battery drained about 15 per cent on a two hour ride with heart rate and power sensors. 

Battery mileage may vary depending on how many sensors you’ve got and if you’re navigating a route. But the fast charging is a great inclusion as it prevents the panicked midnight charge in preparation for the morning ride. 

The charging port cover did baffle us though, it’s just a loose piece of rubber than plugs the socket, so when the device is on charge, you’ve got a tiny rubber grommet to keep track of, which is a task if your desk is a cluttered as ours. 

HammerheadHammerhead Karoo 2 review photo 12

Aside from this, our time with the Karoo 2 was a genuine pleasure. The fluidity of the device is something that really impressed us.

We’ve wrestled with enough devices to realise the user experience here is superior. The act of getting a cycling computer set-up to your requirements and synching everything with Strava and more can be troublesome, with Garmin arguably streamlining this to some extent with its app. Hammerhead has nailed this side of things, as it’s just so simple.

We especially liked the live elevation graphic on climbs, even if there was no route loaded. It’s intelligent and is such a breeze to use. Overarching characteristics of the Karoo 2 in general. 

The Gear LoopHammerhead Karoo 2 review photo 3

The screen is another highlight, it’s clear and crisp (even in bright daylight) and the resolution is powerful enough that it’s easy to make out road names on the map, which proves really handy for on-the-fly navigation.


To recap

It sometimes takes a new player in the market to shake up the established pecking order and Hammerhead has truly placed a cat among the pigeons. The screen is a beautiful thing to behold and interact with and inputs are fluid, making the Karoo 2 a cinch to operate. The features derived from mapping are impressive too, the live gradient readout and smart navigation make the Karoo 2 an attractive proposition if you aren’t interested in delving deep into performance metrics.

Writing by Matt Buckley. Editing by Leon Poultney.