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Hammerhead Karoo 2



Super-responsive and easy to use – a go-to for its navigation and training capabilities combined
Super-responsive touchscreen
Motivational 'live Strava segment' overlay
Excellent on-the-fly navigation
Handy '% of time in HR/power zone' graph
Lots of storage
Easy to download maps
Charging port isn't covered
132g Recommends

This product has been selected to feature in recommends. That means it's not just scored well, but we think it stands out as special. Go to recommends

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Hammerhead Karoo 2 has an improved, compact design with a large enough 3.2inch (82mm) screen for viewing lots of data fields as well as its beautiful map in detail. The device is packed with great features such as a 'live strava segment' overlay, it's super responsive and has excellent navigational capabilities for both planned routes and out-in-the-wild spontaneous ones. There are also plenty of performance metrics, enough that WorldTour team Israel Start-Up Nation use the device.

Dave reviewed the original Karoo back in 2018 and thought it was excellent. The Karoo 2 comes with increased storage, from 16Gb to an impressive 32Gb, added dual Bluetooth Smart chipsets and an upgraded quad-core processor with 2Gb of RAM, for a faster and responsive device that's also capable of handling the regular software updates that Hammerhead installs to continuously improve and introduce new features with.

2021 Hammerhead Karoo 2 - screen 3.jpg

It runs on an upgraded Android 8 operating system that can be paired to iOS or Android smartphones for notifications mid-ride. You can turn messages, calls, voicemail and other apps on and off.

Audio alerts are now included with turn-by-turn notifications. You can set it so the device also beeps for upcoming intervals in workout mode, as vehicles are approaching when paired with the Garmin Varia, as well as for Strava live segments.

There's also a slot for installing a SIM card behind the circular cover round the back. This enables LiveTracking and can be used for WiFi tasks such as syncing rides and receiving notifications.

2021 Hammerhead Karoo 2 - back 2.jpg

Size matters

The Karoo 2 is smaller than its predecessor, measuring 60.3mm wide and 100.6mm tall, and weighing in at 132g. (Down from 98 x 72 x 28mm and 168g.)

2021 Hammerhead Karoo 2 - head unit.jpg

The display is a very good size for viewing the data fields and maps. It is finished with a Dragontrail scratch-resistant screen for some decent defence, and the high definition full colour display has also been treated to reduce glare. It's clear and easy to read as you're riding – only on the brightest days have I had to notch up the brightness a little (and sacrifice a bit of battery life).

The touchscreen responds incredibly well in the dry. It feels much more like operating a smartphone than a cycling computer. In the rain it's not quite as effective, but still very much usable. There are also buttons on each side (four in total) which help when operating if you do run into difficulty when it gets wet or with some gloves.

2021 Hammerhead Karoo 2 - side buttons.jpg

The USB-C port is IP67 rated waterproof. It's proved to withstand prolonged periods of rain, but as the charging port isn't covered I've had some issues with dirt flicking up into it, particularly on muddy gravel rides – my bodge of using electrical tape does the trick, even if it's not the neatest looking solution.

2021 Hammerhead Karoo 2 - charging port.jpg

Mounting system

The Karoo 2 has been developed with its own specific mounting system that works with standard round 31.8mm bars. The dual-locking system has a contact area that's designed to provide support for the device, and Hammerhead also claims its aerodynamic profile reduces drag.

2021 Hammerhead Karoo 2 - bar mount.jpg

Slotting the device in place, it gives a reassuring click and feels securely locked on this mount. There's also a hole for threading through the included lanyard for a touch of extra security along rougher terrain, but even for rides across the bumpier South Downs Way I had no concerns about the device falling off.

2021 Hammerhead Karoo 2 - back 1.jpg

If you have a Garmin-style mount already set up across your bikes, you'll be pleased to know you can slide in the quarter-turn mounting adapter to the back of the Karoo 2 for using with your existing mounts.

Data fields

You can create new profiles for the data fields you need for all the different types of riding you do, and there are lots of different layout options too. There's not been a metric or data field I've wanted that the Karoo 2 doesn't have the option to display.

2021 Hammerhead Karoo 2  data fields.JPG

The device can also show heart rate, power and elevation data in graph form. You can see a bar graph depicting the time in each heart rate or power training zone, for example. This graph also doesn't have to take up much of the screen space – you can choose a layout with six data fields above the graph.

2021 Hammerhead Karoo 2 power graph .JPG

Hammerhead dashboard

If you have a route planned on a platform such as Strava, Komoot or Ride with GPS, or a friend has sent you a web link to one of theirs, it's really quick and easy to transfer onto the device by putting the URL website link into the Hammerhead dashboard 'import route' area. Or you can upload the original file in .gpx, .fit, .tcx, .kml, and .kmz formats here.

Another useful way of importing routes is by adding the Karoo Route Grab extension to your browser (such as Firefox and Chrome). By clicking on this installed icon it'll import the route on the webpage you are currently viewing to your Hammerhead Karoo dashboard, which is even quicker to do.

> GPS cycle route planning made easy – how to plan and follow a bike route

You can also build your own routes on the platform. It's quite basic compared with Strava or Komoot, but it does have some handy buttons such as 'reverse' to change the direction of your planned route and 'return' to go back along the same route you planned for the leg out. Usefully, you can also add a flag along the route to highlight where the coffee stop is or a campsite if you're going on a bikepacking trip.

Here on the Karoo dashboard you can also view your completed activities and sync with third party apps; for example, Strava for starred segments and Training Peaks for your upcoming seven days' worth of workouts. Other apps for ride and route syncing include Komoot, Ride with GPS and Xert.


On the routes page, as well as the name of the route, there's a preview map and details on the distance and elevation, to help you gauge if you're picking the one you had in mind.

It's also handy that you can change how these routes are ordered by newest (date created), gain (elevation), name, length and proximity. If, for example, you click 'length' it would show the longest route at the top, but by double-clicking on 'length' again it displays the shortest first.

If you don't have a route already planned, you can press the '+' in the top right corner and this allows you to create new routes. This is incredibly useful for making a new route when you're on the road itself, or away from home and without a laptop – as long as you have mobile data and you can set up a hotspot to the Karoo 2 or you have a sim inserted.

2021 Hammerhead Karoo 2 route .JPG

As the screen is so responsive it's easy to move the map about to create your desired route on-the-fly. You can zoom in and out to plot the points along the way, or type in a street name or post code.

2021 Hammerhead Karoo 2 creating route on the fly.JPG

For following the route, bright yellow lines and directional arrows point the way.

2021 Hammerhead Karoo 2 map screen.JPG

Turn information pops up on whatever page you're on, with details on the distance left until the turn, as well as an arrow indicating which direction.

The map detailing is fantastic, the navigational overlaps are handy and there are also the audio alerts to ensure you don't miss any turns.

If for some reason you do, it'll reroute you to the next point in the route you're following without going crazy.

More maps

The Karoo 2 has increased total internal storage of 32Gb (26Gb for maps) which is plenty for downloading additional offline maps for cycling holidays abroad. It's also super-easy to download these, as you can do so directly on the device itself.

Hammerhead has broken these down into individual countries so you're just downloading what you need. It's also quick to find the country as they are organised by the continent.

Strava segments

If connected with your Strava premium account, the Karoo 2 will automatically sync the segments that you've starred onto the device. You can enable and disable the segments on the device itself, and you can swipe between four active segment tabs as you ride along at one given time.

As you're riding you get a message about the segment(s) coming up, with the distance counting down – you can swipe away this notification.

2021 Hammerhead Karoo 2 synced segments.JPG

The Karoo's live segment overlay is then displayed as you hit the segment. There's a lot of useful information going on here: you've got the distance covered in the segment, distance remaining in the segment, the elevation profile of the segment, elapsed time since beginning the segment, and some other symbols for tracking progress.

A yellow circle displays your position on the elevation profile and you can also see where you stand compared to other competitors, as well as your previous best and recent times.

There are different symbols such as a carrot representing the best effort recorded by a friend you follow on Strava, a wolf for the best time recorded by the nearest competitor behind you on the segment, as well as the KOM/QOM time, your personal best, recent best (last five attempts) and most recent effort.

2021 Hammerhead Karoo 2 specific segment.JPG

Overall, I found this live segment overlay is great for gauging your effort and it's also super-motivating being able to track your time against different competitors – the visual format also makes it easier to see as you're digging deep in an effort.


The Karoo 2 has a USB-C slot for faster charging, getting the device from flat up to 30 per cent in 30 minutes Hammerhead claims. Hammerhead also estimates battery life as between 7 and over 14 hours depending on the features used and sensors hooked up during usage.

There's a 'battery save mode' in Quick Settings and Settings, which is a handy tool if you really need to conserve what's left.

Usually on rides I've found it lasts around 10-11 hours with all my power meter and heart rate sensors connected up, a route loaded, and flicking between screens.

Riding without a route loaded (but still with sensors) massively increases the life per charge, to around 13 hours.

I've been prompted about installing updates on the device a few times in the test period and continuing ahead with these hasn't affected battery life as far as I can tell.

Ending the ride

Hammerhead has designed the system so it's easy not to accidentally delete your ride. You start the ride by clicking the lower right button and, once moving, press this button again to pause it. Once paused, to end the ride you switch over to the lower left button and then back over to the lower right button to confirm.

At the end of the ride you can rename it from 'morning ride' and you can toggle off or keep on the push button for rides to be immediately sent over to connected third party apps such as Strava and TrainingPeaks.

2021 Hammerhead Karoo 2  end of ride.JPG


Priced at £359, the Hammerhead Karoo 2 is great value for this premium package. Its responsiveness, screen size and quality are matched by the genuinely useful features packed inside including the live Strava segment overlay and the graph depicting the time in each heart rate/power zone.

Hammerhead also has a 45-day risk-free trial. You'll get a free return and full refund if you don't get on. Although from my experience you'll never want to go back!

Garmin's Edge 1030 Plus is a chunky £161 more, although it does come with ClimbPro which is one of the most useful apps reviewer Liam has ever used.

That said, Hammerhead introduced its very own new Climber pop up overlay just last month which is helpful for gauging your effort up the climb and is also clear to read when digging deep. It has a countdown display with the distance and elevation of the climb remaining and also features a colour coded elevation profile which shows which sections are steeper or shallower.

The Garmin 830 is cheaper than the Karoo 2, by £9, but it has a smaller 2.6-inch screen (the Karoo 2's is 3.2in) and it's not as easy to use for on-the-fly navigation.

> Buyer’s Guide: 13 of the best cycling GPS units

The recently released Wahoo Elemnt Bolt v2 is much cheaper at £250 (Mat did a first ride review which you can read here, and his full review will be coming soon). It has an improved screen and with the addition of Wahoo's Smart Navigation functionality you can select destinations directly on the device, but it doesn't have a touchscreen so the on-device navigation is slow.


Overall, the Karoo 2 performs brilliantly for both multi-day bikepacking trips and all-out interval sessions with some Strava segment hunting. Its slimmer than the previous design, powerful as well as responsive, and so simple to use.

The device syncs with the dashboard effortlessly for planned routes, and it's so great being able to make spontaneous routes – as detailed or basic as you please – directly on the device while out on the road (or gravel).

It's reliable and an ideal choice if you want all your usual performance metrics along with impressive and trustworthy navigational support.


Super-responsive and easy to use – a go-to for its navigation and training capabilities combined test report

Make and model: Hammerhead Karoo 2

Size tested: One Size

Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Hammerhead says: 'Karoo 2 is designed to put your cycling experience first. Powerful features make it simple for cyclists to do structured workouts, follow routes, connect to Strava and other third parties, and get the most out of every ride."

Tell us some more about the technical aspects of the product?

Hammerhead lists:

Dragontrail glass panel with Acid Etched matte finish

High resolution 3.2" display panel with 16.7 million colours supported

responsive touchscreen, with droplet rejection

Fully controllable with buttons

Overmoulded shock-reducing bumper

Waterproof SIM card cover

Water and dust proof to IP67 rating

2500 mAh high capacity battery

12 hours of ride time

UBS-C with fast charging

Waterproof USB-C port

Quad core 1.1Ghz, CPU with 2gb of RAM

32 gb of storage (26gb for maps)

3-axis accelerometer, magnetometer and gyroscope


Hammerhead Mounting System (patent pending)

Standard ANT+ and Bluetooth Smart sensor support

Varia Radar support

Shimano Di2 support

Strava live segments

Upload activity to 3rd party services

TrainingPeaks workout integration

Sync routes from 3rd parties

Instant rerouting

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for weight (if applicable)

The Garmin 1030 Plus is a touch lighter at 126g.

Rate the product for value:

Tell us how the product performed overall when used for its designed purpose

Fantastic navigational functionality and great for following your performance metrics as you ride. The high definition touchscreen clearly shows your data and map detailing, and the device is a delight to use thanks to its incredible responsiveness.

Tell us what you particularly liked about the product

The incredibly responsive touchscreen and how that made on-the-fly routing so quick and easy.

Tell us what you particularly disliked about the product

Lack of charging port cover as dirt can get in.

How does the price compare to that of similar products in the market, including ones recently tested on

The Karoo 2 is £161 less than Garmin's 1030 Plus, but the Wahoo Elemnt Bolt V2 is £250, which makes it £109 less than the Karoo 2.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

Absolutely great to use for both multi-day bikepacking trips and all-out interval sessions with some Strava segment hunting. The price may seem quite high, but for the spec it's well worth it.

Overall rating: 9/10

About the tester

Age: 23  Height: 177cm  Weight: 62kg

I usually ride: Road bike  My best bike is:

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, cyclo cross, commuting, touring, club rides, sportives, general fitness riding, Gravel riding, indoor turbo and rollers, track

Add new comment


zeeridesbikes | 2 years ago

One more thing I noted it would have been better if they had introduced faster charging through usb-c. 30% in 30 minutes isn't particularly fast. 

Jetmans Dad replied to zeeridesbikes | 2 years ago
1 like
zeeridesbikes wrote:

One more thing I noted it would have been better if they had introduced faster charging through usb-c. 30% in 30 minutes isn't particularly fast. 

The list of specs quoted above does state USB-C with Fast Charging. Could be they didn't actually hook it up to something capable of performing the fast charging. If you plug a device into most PC USB sockets, they will charge at slow/standard speed regardless of whether or not the device itself is capable of fast charging. 

Randall_Memphis | 2 years ago

You said that 1030 has ClimbPro. It's worth to note that very similar feature is in Karoo2, called Climber. It was added a couple of weeks/months ago so you may want to review your review.

zeeridesbikes | 2 years ago
1 like

I got mine a couple of weeks ago. It's a great unit but there are a few issues. For some reason my completed rides are longer than the route, this is despite manually entering my wheel circumference for my speed sensor.
The battery life is very average but it's a trade off for the great screen. 

Navigation is brilliant and the upcoming elevation profile is much clearer than garmin/wahoo. Having the choice of buttons and touch screen is a bonus.  Hopefully it'll keep on getting better with regular software updates.  

naynay | 2 years ago

I keep reading in reviews of the Karoo 2 same with this review that it has no charge port cover.
Mine came with two rubber charge port grommets that push in the USB-C port of the Karoo 2 to seal it from the rain.
They are a good fit and have no doubt will do the job.

HollisJ replied to naynay | 2 years ago

One of mine fell off after a couple of rides, which was disappointing. I can't imagine it would stay on for more than five minutes on a gravel ride!

Lostmariner | 2 years ago

Not sure why some come with a USB port cover and some don't. Mine and two of my friends units all came with rubber covers out of the box.

peted76 | 2 years ago

Lovely bit of kit, very responsive, but a word of caution, it is a bigger unit than the usual.. and a mate of mine brought a 3rd party carbon mount which snapped while we rode over some rough tarmac, it wasn't 'tethered' and scratched the hell out of it. 

sparrowlegs | 2 years ago

Just ordered one of these from Wiggle for £316.

I got stranded after a road on my usual route was closed (I wasn't using the 530 to navigate the route at that point) I used the 530 to navigate me home and it took me WAY out of my way and on some pretty rough routes (right next to perfectly good roads). It was even trying to redirect me when I could see my street. So frustrating and slow to write the route too. 

I'll see how the Karoo2 performs this weekend.

wycombewheeler replied to sparrowlegs | 2 years ago
sparrowlegs wrote:

Just ordered one of these from Wiggle for £316.

I got stranded after a road on my usual route was closed (I wasn't using the 530 to navigate the route at that point) I used the 530 to navigate me home and it took me WAY out of my way and on some pretty rough routes (right next to perfectly good roads). It was even trying to redirect me when I could see my street. So frustrating and slow to write the route too. 

I'll see how the Karoo2 performs this weekend.

Garmin is not a good route planning tool.

RoubaixCube replied to sparrowlegs | 2 years ago

I find the problem with that is the base maps. Garmin maps generally lack a lot of details at least when it comes to their cycling GPS units.

Upgrading the maps to Open Street Map will open up a lot more of the city to you. DC rainmaker's website has a step by step guide on how to do something like this

amazon22 replied to sparrowlegs | 2 years ago

How did you get the discount? I had a time limited offer from Wiggle for a similar amount, but when I went to check out, it reverted to full price, so I left it there.

alexcr | 2 years ago
1 like

I've had mine a few months now, and I'm glad I got it over the Garmin I was considering to replace my Edge 1000, which was finally starting to break down. Unlike Garmin who take the approach that the features you have when you buy it are all you'll ever have, Karoo are really good about pushing out regular updates adding and refining new features. This last month they've added a new hill climb feature a la Garmin's (I think, I never used Garmin's version because they don't update their existing models!), and there's been lots of nice improvements to things like data fields and phone notifications while I've had mine. And I can see that most features are being released simultaneously for the Karoo 2 and 1 at the same time (except those that need hardware that the Karoo 1 doesn't have), so hopefully there's years of feature improvements to come for mine. 

ads-b | 2 years ago

FYI- mine came with a rubber bung.

Although I've now sent the thing back as despite all the amazing things about it I had a some things which I won't compromise on. I'va had feedback from Karoo (excellent customer service BTW):

-No app to push routes without wifi- lots have people have asked for this, but needs them to deveop android and iOS apps. That sounds like it's a way off

- No direct way sending garmin routes over- Garmin shut them down on this as they are a competitor. Theres a workaround, but needs wifi (until an app comes along) and you to export the route to a gpx file from Connect. All too long winded for me.

-No map notification of upcoming turns in data screen- it will show you an arrow and road name. But that isn't enough for me. If you have two roads right next to each other and can't see/don't have time to see the signs then you could make a wrong turn.

- No live tracking with Bluetooth to phone- as it needs an app then it just won't do it. You can get round it by tethering to your phone, using a phone app and not the K2, or putting a sim card in. But it isn't as easy as my 15yo Garmin

Until they sort out the apps and the map notification of turns, I won't be buying it. I have simple needs which my old 810 has, and the K2 doesn't. They are working on these, but by then it may be cheaper or another competitor comes up with what i need. So I sent it back.

Steve K | 2 years ago

I know it's a different reviewer, but I notice you haven't marked this down for the size of the bezels as with the Garmin 1030 Plus.

Secret_squirrel replied to Steve K | 2 years ago
1 like

Its an odd thing to mark down for in the first place.  You need a "finger gap" down the side if you're wearing gloves anyway.

RoubaixCube | 2 years ago

For those who care -- You can buy these rubber/silicone USB C port covers on amazon.

Quite an oversight by hammerhead especially given the premium price of the product.

zeeridesbikes replied to RoubaixCube | 2 years ago

Mine came with one in the unit and a spare in the box. 

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