Hammerhead Karoo 2 review: Full-featured GPS bike computer that keeps getting better

The Hammerhead Karoo 2 offers pretty much everything you could need from a GPS cycling computer

T3 Platinum Award
Hammerhead Karoo 2 review: Pictured here, the bike computer from two angles on grey background
(Image credit: Hammerhead)
T3 Verdict

An excellent, full-featured head unit, the Hammerhead Karoo 2 has pretty much everything most cyclists could need. It's intuitive to use, while its new climber feature sets it apart from other devices on the market.

Reasons to buy
  • +

    Simple to set up

  • +

    Intuitive touch screen interface

  • +

    Climb feature is excellent

  • +

    Will keep improving as more features are added

Reasons to avoid
  • -

    Some of the display choices are restrictive

  • -

    Fewer third-party app integrations than other devices

Hammerhead Karoo 2 review in a sentence: a premium bike computer that gets better and better, one update at a time.

Since its release, the Karoo 2 has gathered a loyal fanbase and established itself as a genuine rival to Garmin and Wahoo, two of the best cycling computer manufacturers on the market. Hammerhead keeps adding new features such as the Predictive Path Technology update to make the device even more appealing to riders of all kinds.

However, the Karoo 2 is not a cheap device – should you buy one? Read on to find out.

Hammerhead Karoo 2 review: Price and availability

The Hammerhead Karoo 2 is available to buy not directly from Hammerhead and selected third-party retailers for a recommended retail price of $399 / £359 / AU$639.

For the latest price information, check out the widgets at the top and bottom of this review.

Hammerhead Karoo 2 review: Setup

First things first, the Hammerhead Karoo 2 is really simple to set up. When you power it up, on-screen instructions take you seamlessly through the setup process. First up, you connect to wi-fi and update the software to the latest version, before downloading maps for your region. The map file for the UK is around 3GB so this can take some time, depending on your download speed. We also needed to download this twice as it seemed to disappear the first time, but this seemed to be a one off. 

The next step is to connect to your phone and sensors. Phone connection is via the Karoo Companion app, which is not really a companion as its sole purpose is to allow the Karoo 2 to receive alerts such as messages on screen. If you’re pretty in demand, you may want to turn off the audio alerts for some apps as it can get quite incessant at times. We tried the Karoo 2 with a Garmin Forerunner Ant+ HR monitor and Favero Assioma Duo power meter pedals and they worked perfectly. Pairing was simple and the sensors reconnected quickly when the Karoo 2 was switched on and off.

Hammerhead Karoo 2 review supporting images

(Image credit: Amy Sedghi)

Hammerhead Karoo 2 review: Display and interface

The display of the Karoo 2 is a real selling point. It has a large 3.2-inch screen with a resolution of 480*800 and 16.7 million colours supported. I’m not sure anyone can imagine what 16.7 million colours look like, but the pre-loaded image of a mountain vista on the profile screen demonstrates the photo quality display pretty awesomely. As you’d expect with those stats, colours and contrast are vivid, while the brightness is easily controlled using a menu accessed by swiping down from the top of the screen. This is also where you access other settings like sensor and third-party app connections.

During the ride, you can select between the map screen and the sensor screen, while the choice of sensors shown on the sensor screen can be controlled via profiles such as Cadence+HR, Power+HR, Indoor: Power etc. There is also a Got Hills? Profile, which shows ascent, grade and historical elevation. If you have this profile selected you can no longer see power, cadence or HR though. It would be better if this was an additional screen, which is the case on devices like the ELEMENT series. 

Hammerhead Karoo 2 review supporting images

(Image credit: Amy Sedghi)

Hammerhead Karoo 2 review: Routing and navigation

When it comes to routes, there are two main ways to use this on the Karoo 2. The first way is to import them from your favourite apps like Komoot or Strava by connecting to the apps on the device itself. This automatically loads the list of available routes on the routes page with thumbnail maps, which is useful if you haven’t given your routes descriptive names as you can immediately see where they are on the map. The feature also removes the faff of downloading and uploading GPX files that are required on other devices. 

The second way to use routes is to manually create them on Hammerhead’s dashboard. This works in a similar way to other manual route creation apps. There is a menu to choose between road, gravel and mountain bike surfaces and the option to use OpenCycleMaps as the base map. The interface works well but it doesn’t have the functionality of other apps, for example, if you wanted the ability to use Strava’s heat map to find popular routes. Experienced users will most likely continue to use one of the third-party apps.

For navigation, the display is clear and bright and routes are easy to follow from the map screen. If you are on the sensor screen turn-by-turn directions pop up, which works well. However, they could be improved if the pop-up also showed a small map of the turn, which wouldn’t take up too much space on the Karoo 2’s large display. If you do end up off route, then the Karoo 2 offers dynamic rerouting to get you back on track. 

Hammerhead Karoo 2 review: Climb feature

The Karoo 2’s new ‘Climber Without a Route’ feature is designed to automatically detect when you are about to ride up a hill, regardless of whether you are using a pre-loaded route, thanks to AI predictive technology. 

We tested the Climber feature on a hilly 100km ride in the Kent hills on a route we were familiar with but didn’t have loaded on the Karoo 2. We were pleased to see that the feature performed brilliantly. Climbs were identified quickly and the gradient map appeared on the screen automatically. This shows the profile of the climb, your current position and the distance to the summit. 

This feature would come in incredibly useful when cycling in an area you are unfamiliar with. If you suddenly find yourself on a climb, it’s easy to decide whether to push on or back off based on how long is left and how savage the gradient will be round that next corner (equally, it could help you decide if you should just turn around and go back the way you came). The Karoo 2 also keeps count of how many climbs you have done so you can smugly pat yourself on the back at the end of the ride.

Hammerhead Karoo 2 bike computer mounted on a road bike

(Image credit: Hammerhead)

Hammerhead Karoo 2 review: Verdict

The Hammerhead Karoo 2 is an excellent, full-featured head unit that has everything most cyclists could need. Its Android operating system makes it intuitive to use for any smartphone user, which is practically everyone.

The new Climber feature is excellent and works brilliantly, setting the Karoo 2 apart from other devices on the market. Perhaps even more exciting is the fact that this feature has been added to the existing device, which validates the point Hammerhead makes on the first screen when you turn the device on it will never stop improving.

It’s refreshing to see a device that improves over time, rather than relying on the user to just purchase a new unit each time there are updates. This could be the key factor in deciding which head unit to purchase for many buyers and I'm excited to see what Hammerhead has lined up for the Karoo 2 next.

Hammerhead Karoo 2 review: Also consider

The Wahoo ELEMNT BOLT is cheaper than the Karoo 2 but you'll need to set everything up in the Wahoo App instead of on the device. The Karoo 2 has the edge in terms of customisation during the ride - it’s easy to change between different profiles showing different sensors, without the need to get your phone out. 

Need the best of the best, the cream of the crop of cycling computers? Check out the Garmin Edge 1030 Plus, it's "simply the best cycling computer around" as our review of the unit concludes. The sheer amount of features that are crammed into such a tiny computer is almost bamboozling. Garmin’s navigation and routing are great and the bright, responsive touchscreen is super easy to use. 

Amy Sedghi
Amy Sedghi

Amy is a freelance journalist who writes for various publications, including The Guardian, National Geographic Traveller, Telegraph, The Evening Standard, The Independent, Refinery 29 and more. She loves travelling and cycling.