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Hammerhead Karoo 2 review

The smaller, lighter, and more capable Hammerhead Karoo 2 is one of the best cycling computers you can buy right now

Hammerhead Karoo 2 cycling computer attached to barfly mount on handlebar
(Image: © Aaron Borrill)

Our Verdict

With the best screen and navigational metrics in the game, the Hammerhead Karoo 2 brings a premium experience to a broader audience


  • Unrivalled touchscreen
  • Stellar navigational prompts
  • Audio notifications
  • Refined aesthetics
  • Weight more in line with rivals


  • Brand loyalty of rival users

We reviewed the Hammerhead Karoo 1 cycling computer back in 2019 and came away feeling impressed by what it offered users in terms of a holistic cycling computer experience.  As one of our recommendations in our best cycling computers buyer's guide, it hit all the markers when it came to its high-definition screen, intuitive functionality, advanced mapping and GPS capabilities but was ultimately let down by the market's propensity for smaller, slimmer units.

It appears as though the company took all criticisms to heart and has redefined the concept altogether with its latest offering. According to the brand, the Hammerhead Karoo 2 is the 'most powerful cycling computer on the market'. The new model is lighter, smaller, and more premium-looking than its predecessor but it's also jam-packed with an impressive feature set and class-leading screen resolution. 

These attributes caught the attention of WorldTour outfit, Israel Start-Up Nation, who are now using the Hammerhead Karoo 2 to track all performance metrics. The team has been deeply involved with the development which has been an ongoing process, providing real-world feedback to keep improving the user experience. 

In a segment spearheaded by players from Garmin, Wahoo, SRM and Stages - can the Hammerhead Karoo 2 make any inroads in this hotly contested space?

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Hammerhead Karoo 2 cycling computer design details

The embossed Hammerhead logo of the prototype has been replaced with a bolder metallic-silver finish (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

Navigational prompting is superb and the audio alerts ensure you will never miss a turn again (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

The 3.2in/82mm display is finished in a responsive, scratch-resistant DragonTrail glass for improved resilience and user experience (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

Most notable change comes in the form of the Karoo 2's dimensions and weight (Image credit: Aaron Borrill)

Design and aesthetics

We spent a couple of weeks sampling an engineering prototype of the Hammerhead Karoo 2 and, while it wasn't 100 per cent representative of the final product, we could tell by the design and packaging that the company was on to a winner. The differences between the finished product and prototype are minimal but in line with what we were told during our video call with the design team. As a result, the embossed Hammerhead logo on the top edge has indeed been replaced with a bolder metallic-silver finish and the unit's overall colour is a shade darker than before.

In terms of dimensions the Karoo 2 is 40 per cent smaller and 33 per cent lighter than before, and tips the scales at 135g (actual weight) - 10g heavier than the prototype. In fact, according to Hammerhead founder and CEO, Piet Morgan, the new model is more in line with what the company originally envisaged for Karoo 1.

The limiting factor with Karoo 1 came in the form of the battery, power requirements and internal titanium skeleton. These attributes made it exceptionally difficult to produce on a smaller scale but, with version 2, the engineers and designers were able to radically reduce the unit's dimensions without sacrificing much of the screen real estate.

In fact, in terms of height, the screen remains on par with the Karoo 1, the only significant difference being that it's a touch narrower which does nothing to limit the user experience. 

Like its forebear, the Karoo 2 is built around a high-definition touchscreen. The 3.2in/82mm display is finished in a responsive, scratch-resistant DragonTrail glass for improved resilience and user experience - even in wet weather. 

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Hammerhead Karoo 2 cycling computer

Side by side: Hammerhead Karoo 1 (left) vs Hammerhead Karoo 2 (right) (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

Karoo 2 eschews the universal 'Garmin' mount for a unique, Karoo-only linear-lock system (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

Left to right: Hammerhead Karoo 1, Hammerhead Karoo 2, Wahoo Elemnt Roam, Stages Dash M50, Stage Dash L50, SRM PC8 (Image credit: Aaron Borrill)


Hammerhead's modus operandi with Karoo 2 was to neatly shoehorn the highest performing components into the smallest possible package to help bring it more in line with its rivals from Garmin and Wahoo.

This presented a unique set of challenges because the Karoo 2's quad-core, smartphone-grade Qualcomm processor, a high-definition screen and a cellular radio require a bigger power source and increased antenna space but the design was able to keep things rather diminutive.

The device itself represents a radical evolution over its predecessor but the core ethos and functionality remain the same. While the Karoo 2 uses a touchscreen, four buttons (two on each side) gives the user complete control over the device when it's raining or navigating trickier terrain where touchscreen operation might not be possible. These buttons together with the outer edge of the entire unit are covered in an elastomer-based material for added grip and protection against impacts. It's the screen, however, that has made a lasting impression on many testers and users - pro riders included. 

Isreal Start-Up Nation team rider Dan Martin has been using the device since December and has been impressed by its screen and mapping. 'It’s an incredible device, the screen is phenomenal and level of detail with the maps is one of its best parts', says Martin. 'It’s a level of technology that hasn’t been seen in cycling computers yet.'

In terms of hardware specifications, the Karoo 2 is built around connectivity - and Hammerhead has waxed lyrical about its smartphone integration and push-notification functionality. It features a brace of Bluetooth, low-energy chipsets that connect to ANT+, WiFi, Smartphone and, of course, GPS, 3G and 4G which lets it talk to any device - iOS or Android - and operate in any situation. Flip the device over, unclip the circular cover and you'll be able to slide in a SIM card - allowing you to navigate anywhere, receive notifications and upload your activities without reliance on WiFi.

The Karoo 2 also benefits from a USB-C charging slot for faster charging - 30 per cent in 30 minutes and 50 per cent in an hour. Of course, connecting to multiple sensors as well as utilising the device's mapping capabilities will have a bearing on battery life which Hammerhead pegs at 12 hours. While I've been averaging around 10 hours per charge I have managed to stretch that to an impressive 14 hours by running the device without any sensors or navigational prompting. 

Another key focus came in developing a Karoo-specific mounting system. In this case, a unique, dual-lock mechanism which ensures the unit remains planted and balanced during operation. According to Hammerhead the Garmin-developed 'quarter-turn' paradigm is better suited to smaller/lighter units and isn't conducive for the modern cycling computer. Hammerhead's new linear-lock design has a larger contact area that provides more support for the device and is also compatible with time trial/tri cockpits. Those who prefer the now-universal quarter-turn mount or have Garmin-style brackets set up across myriad bikes can just slide in an adaptor plate (the adaptor plate is available as a pre-order option only). We prefer this option.

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Hammerhead Karoo 2 cycling computer's unique mounting interface can work with Garmin using an adaptor

The device uses a new linear-lock design but an adaptor plate helps with compatibility across Garmin-style mounts (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

Hammerhead's unique linear-lock mechanism keeps the unit planted and balanced during operation (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

New linear-lock mounting system ensures better support of the unit. It's also also compatible with time trial/tri cockpits (Image credit: Aaron Borrill)
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Hammerhead Karoo 2 cycling computer

The included mount is compatible with standard 31.8mm round handlebars (Image credit: Aaron Borrill)

User experience

Like Karoo 1 it runs on a fully customised Android operating system - Android 8 to be exact. The software is identical across both the Karoo 1 and Karoo 2. Of course, you'll need to create an account but this gives you access to further customisation and route-building options, viewing your activities as well as updating your profile. As expected, it's also fully compatible with third-party apps such as Strava or Training Peaks. 

The Hammerhead Karoo 2 is simple to operate. I'd even go as far as to argue it's more intuitive than that of its rivals, Garmin and Wahoo included. The processing speeds make it super responsive with minimal delays - granted you continually install the updates. As an individual who prefers using a cycling computer to track performance metrics, I was mighty impressed with the device's navigational proficiency. In terms of navigation, it offers unrivalled levels of accuracy, directional prompting and mapping detail. 

The more I've been using it as a navigational tool the further I've been venturing into unchartered territory. Most of these rides have been done by following courses - either those of friends or routes I've personally created using the Hammerhead dashboard route builder function. It's all very straightforward. Navigational prompting is superb and the audio alerts ensure you will never miss a turn again. It's also worth noting that you needn't be on the map screen itself to receive turn-by-turn navigation - the directions will show up on any screen.

The bulk of my testing comprised regular GPS tracking, which also took into account sensor compatibility and checking whether or not it drops or loses signal. It doesn't - in fact, it does a pretty stellar job when it comes to displaying and tracking various performance metrics, made all the better by using Strava Live Segments to help track improvements on your local segments. 

Any areas of concern? Well, for the most part, the Karoo 2 has been performing flawlessly. I did have some concerns around the exposed charger port on the bottom of the device and the possibility of dirt, rainwater or moisture creeping in and damaging its innards but so far so good. In fact, the only issue I've experienced in terms of rain pertains to the screen. While the screen surface is hydrophobic and works brilliantly when it comes to violent downpours you'll need to operate it using the buttons.


The Hammerhead Karoo 2 is unquestionably more in line with the contemporary cycling computer formula than its forebear - it's smaller, slimmer and lighter but it's also super fast when it comes to processing speeds, mapping, and route guidance.

Hammerhead is pitting it directly against the segment's top players and, quite frankly, it possesses all the attributes to challenge the Garmin 1030 for top honours, with its improved aesthetics, palatable dimensions and killer touchscreen. 

At $399 the Karoo 2 is not the cheapest option around but it will find favour with a whole new customer base wanting something new and different. Besides, the company's involvement with Israel Start-Up Nation is likely to broaden its appeal even further. Looking at its chief rival, the Garmin Edge 1030 and 1030 Plus which retail for $200 more, the Karoo 2 offers a worthy alternative for those willing to embrace change and move into an intuitive and user-focused ecosystem.

Personally, the Hammerhead Karoo 2 has become my go-to device when it comes to performance metric tracking and navigational capabilities - it's also incredibly reliable compared to some of its rivals (it never crashes or freezes). As a package, I'm inclined to say it's the best cycling computer on the market - five stars.

Tech Specs: Hammerhead Karoo 2 cycling computer

  • Price: (Starting from) US$399 / £359 / €399 
  • Connectivity: ANT+, Bluetooth, WiFi, cellular 
  • Operating system: Android 
  • Water-resistant: IPX7 
  • Dimensions: 100.6 x 60.8 x 19.3mm
  • Weight: 123g claimed, 135g actual
  • Storage: 32GB
  • Navigation: OpenStreet Map
  • Claimed battery life: 12-hours   
  • Colour touchscreen: Yes
  • Screen size: 3.2in / 82mm diagonal

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