My Hammerhead Karoo 2 Review: Why Did I Wait So Long…?

In this post I review the Hammerhead Karoo 2. Which is a bike computer. And a very good one.

I bought the Karoo 2 way back in August 2021 but only managed to get it out of its box in August 2022 due to [insert unsatisfactory excuse here].


I’m glad I did though. Over the last 9 months, I’ve grown to rather like it.

It’s not a supernew device. The original clunky looking Karoo was launched in 2017 with the more svelte Karoo 2 following in the second half of 2020.

Hammerhead Karoo 2 device

I’ll save you too much of the spiel. Basically it’s a high end touchscreen bike GPS, built on the Android operating system rather than a bespoke Hammerhead one.

And, as it turns out, it’s a VERY viable alternative to Garmin and Wahoo at the top end of the bike computer market.

Watch The Video

There’s a YouTubez version of this post! And you can WATCH IT HERE! You LUCKY people! (stop shouting)

Also, if you want to see how the Karoo stacks up against the competition, you should read my post comparing the best touchscreen bike computer to buy in 2023.

The Basics

The bike GPS market is, as of mid-2023, sufficiently mature that there’s a set of features common to all mid and higher-end devices.

The Karoo 2 has all of them, except one. Hmm, mysterious….

Hammerhead Karoo 2 ASMR

In no particular order, the Karoo 2:

  • Uses the magic of satellites to track and record your bike rides;
  • Connects to ANT+ and Bluetooth sensors to display and record session data;
  • Links to and controls your smart trainer;
  • Whispers sweet Bluetooth notifications to your smartphone; and
  • Has full on-board navigation.

Hammerhead Karoo 2 trainer workouts

And before you start worrying, the missing feature – syncing ride data with your smartphone via Bluetooth – is sort of redundant. I’ll come to that later in the post.

The Karoo 2 is built on capable hardware. There is no lag when moving around the device. It might not be iPhone quick but it feels zippy enough as a bike computer.

Hammerhead continues to develop the software operating system, releasing updates and new features every couple of weeks, which is, of course, wunderbar.

This Karoo 2 firmware refresh thingummy seems to get called out a lot – in much more reputable media establishments than this one – and it’s undoubtedly a good thing. But Garmin and Wahoo also update firmware on a fairly regular basis – so I’m not sure it’s the differentiating factor that people seem to think.

That said, one of those software updates brought the CLIMBER feature. Which is a differentiating factor. And I’m a massive fan. So let’s sink our teeth into the meat of the review there.


My hands-down favourite thing on the Hammerhead Karoo 2 is the CLIMBER feature. All caps.

Hammerhead Karoo 2 Climber detail

As a cyclist, if there is anything weaker than my 43-year old legs, it’s my 43-year old mental resolve. On longer and harder rides, I struggle not knowing how much distance is left or how many metres of total ascent are left to accrue.

The same applies to individual climbs. I feel a lot happier if I know where a climb steepens, where it flattens to offer respite and whether there is another vicious ramp around the next bend.

So the elevation screen is my friend on a tough ride.

CLIMBER on the Karoo 2 is a super-dooper version of the elevation screen. And the best bit: it kicks in on a climb, even when you’re not following a pre-defined route.

Hammerhead Karoo 2 climber handlebars

Using mysterfarious software whizzbangery and, presumably, the gradient data built into the map file, the Karoo 2 will work out if you’re heading towards a substantial climb and then present you with a screen of useful data to quieten the mental monkey.

The format of the screen is colourful and clear, and I like it.

The climb is divided into 500 metre chunks, each of which is colour coded by gradient. Dark green is easier, getting steeper as you move through yellow, orange and red. Thankfully I’ve not yet hit purple.

Hammerhead Karoo 2 climbs

The horizontal grid underneath, again colour coded, shows the gradient over the next few 100 metre increments. So you get the full extent of the climb on the chart, important for my long term mental state, and then more granular data in the grid.

Apparently accuracy can be an issue at the 100 metre level. At this scale, the number shown can be distorted by incorrect spikes in the underlying mapping data. I’ve generally found it ok but then I’ve not been using the Karoo 2 in mountainous terrain with switchback bends, where the issue is more pronounced.

Either way, I like the CLIMBER screen itself. It does a good job of cooling my worry jets. And I particularly like that it pops up for an upcoming climb on any ride, not just those where I’m following an uploaded route.

Looks, Size And All That Fandango

I was expecting the Karoo 2 to be chunky, bordering on ugly. In reality it’s neither.

Whilst it’s hardly a small bike computer and it doesn’t have any aero pretensions, it looks sufficiently smart and modern in the out-front mount.

Hammerhead Karoo 2 size comparison

It’s a bit bigger than my Edge 830 (and my 840), sort of similar to my Wahoo ELEMNT ROAM and a bit smaller than my Edge 1030 Plus (and 1040). Not too big; not too small. Like the porridge.

The mount fitting on the back is Hammerhead’s own design. You sort of slide it on and it clicks into place. Slight twist and slide off to remove, or that’s the theory. It feels very secure in the mount, VERY secure, but I struggle a bit with getting it out [MONT ADOPTS BLANK LOOK].

Hammerhead Karoo 2 mount fitting

Actually I struggle with it a lot. It’s a pain.

I find the Garmin system a lot easier – I guess 9 years of experience does that to you – but I’ll persist with the Hammerhead one in the hope I get the hang of it. The Karoo 2 comes with an adaptor if it all gets too much, or if you have a precious family heirloom Garmin handlebar mount that you can’t give up.

Hammerhead Karoo 2 mount adaptor

But who cares about handlebar mounts? The Karoo 2 is a nice looking unit. It looks smart and very much the part whence attached to my bike.

And! If you find yourself gazing at the Hammerhead for any period of time, it won’t be the case that draws the eye. It will be the very beautiful display.

So why don’t we talk about that…


Hoo mamma.

The Karoo 2 comes with a glorious, vibrant matte display, which, according to the specs, is made from Gorilla Glass. I’d have guessed unicorn piss.

It’s bright. It’s colourful. It’s high definition. I likes it very much.

Hammerhead Karoo 2 booting up

If you’ve read my ELEMNT BOLT V1 versus V2 comparison post, you’ll know I really like the screen on the newer version of the BOLT.

I.M.H.O. the display on the Karoo 2 is even better. It’s certainly less reflective in bright sunlight than the Edge 830 and 1030 Plus and clearer to read whilst riding.

Hammerhead Karoo 2 and Edge 830 on handlebars

Here are some of my amateurish shots that probably don’t do the Karoo justice.

The Karoo isn’t just a pretty face. It’s a touchy face. Hmm…

I’d describe the touchscreen as adequate, which isn’t meant to be a euphemism for ‘bad’.

We’ve perhaps been spoilt by highly responsive smart phones and tablets when it comes to finger on screen action.

The Karoo 2 touchscreen isn’t iPhone fast but it’s reasonable for a bike computer that has to put up with regular road soakings. It’s certainly on a par with touchscreen Garmin Edges, from whence the competionary pressures arise.

User Interface

Whether we’re talking touchscreen or button-reliant variants, the majority of the functions and settings on higher end Garmins are controlled on the device itself. As a result, the Garmin UI, at least pre the Edge 1040/840 generation, makes copious use of menus and sub-menus.

Hammerhead Karoo 2 settings

Wahoo ELEMNTs don’t currently have touchscreens so they rely on physical buttons, mainly on the front, with a smartphone app doing a lot of the heavy lifting from a settings perspective. Aside from core functionality, the things you can do directly on an ELEMNT device is pared back to make the user experience clean and simple.

The Karoo 2 offers a blended path, both in terms of the user interface – how features are organised and presented on the bike computer – and the controls.

The Karoo 2 has both the touchscreen and four physical buttons on the side of the device, with certain core functions, such as scrolling through the ride data screens, controlled by either method.

Hammerhead Karoo 2 side buttons

Hammerhead doesn’t mirror Garmin’s approach of menu after menu. It’s much more like a smartphone interface, with intuitively designed screen elements and copious amounts of finger swiping. To my eyes, and stunted digits, it’s attractive and pleasing to use.

Hammerhead Karoo 2 user interface

Nor does it rely, big Wahoo style, on an app because, get this folks, there isn’t an iPhone app (there’s a basic Android one but only mirroring phone notifications).

WTAF. Who designs a bike computer without an app?

Hammerhead Karoo 2 no app

But hold on, young grasshopper, let’s actualise together and achieve clarity.

The Android, i.e. smartphone software, based UI is the app, and the Karoo 2 is the smartphone. You can even put a SIM card in it.

[Brrssssskkkk! Mind blown…]

Anyway, I very like the Karoo’s user interface.

For the headline features, like CLIMBER and the integration with Strava Live Segments, the screens are daubed with eye-slapping splashes of colour. To this pre-school art critic, they look the business.

Hammerhead Karoo 2 navigation

The screens are intuitively laid out. Where needed, Hammerhead adds subtle text descriptions to make clear what an option or a screen is there for.

Once you’ve got the hang of them, changing the settings on a ride profile, such as adding a data page or field, is straightforward.

You can tweak, preferably not twerk, to your hearts content.

Maps and Navigation

Navigation is another Karoo 2 strength, certainly for road-verts like me.

Maps are colourful with plenty of detail, but not too busy that they become difficult to follow. There is loads of space on the device, 32 Gigacrackers, in which to download maps for when you’re off the grid.

Hammerhead Karoo 2 map screen

Playing around with the map whilst on a ride, zooming in and out, squiggling around, is responsive with little noticeable lag. For choice, the icon that unlocks the view, allowing you to scroll around, is slightly easier to hit on Garmin, mainly because it uses an ugly great hand icon. The Karoo’s more subtle lock icon can require a few fat finger thrusts before the ferret is fettled.

Getting routes onto the Karoo 2 is a piece of picnic. You can create them on the device or via the Hammerhead website. With a linked Strava account, any routes you create and favourite will automatically appear on the Karoo 2. For RideWithGPS, again after linking accounts, you just copy the route URL into this box and it magically appears both in your Dashboard and on the Karoo.

Hammerhead Karoo 2 dashboard

You can even copy in random Google Maps routes and it still works! It’s not clear why this function fills my loins with such warmth.

One note of caution on navigation. You can’t switch off automatic re-routing. I know some users (and reviewers) have pointed this out as a pain if you’re doing a quick sideways shimmy to a cafe but planning to rejoin the original route. Before you get the chance, the Karoo 2 has recalculated you a new route.

I’ve not found this a particular issue, but then I rarely get chance to have cafe stops. Sad face.

A Quick Word On Bluetooth and 4G

Bear with me. This is the missing feature I mentioned up top.

The Karoo 2 uses Bluetooth to communicate with Bluetooth sensors secreted about your bike and your person. It also uses it to flash up texts, emails and new TikTok dance notifications on the Karoo screen.

Hammerhead Karoo 2 phone notifications

What the Karoo doesn’t do, as far as I can tell, is use Bluetooth to sync with your phone. When you finish a ride, it won’t send the file to your iphone, and thence on into the ether. Or Strava.

In the other direction, your phone isn’t sending route files to the Karoo 2.

This is because, and young man we’ve talked about this, your Karoo 2 is your phone.

Hammerhead Karoo 2 sim card

To do said syncing, actually to your Hammerhead account, which contains all your ride and route data, the Karoo 2 needs to connect to the information highway matrix web via wifi or using the SIM card that you’ve inserted into its rear passage.

If you’re using a SIM, you can also enable live tracking natively on the Karoo 2, rather than relying on your phone and its battery. I can’t say a lot more because … I’ve not tried it. Soz. LOL. That said, I don’t use these features on my Wahoos and Garmins, so do I really care?

Hammerhead Karoo 2 live tracking

If you’re going sans SIM, you can always connect the Karoo to your phone’s wifi hotspot for on-the-move route transfers and uploads. Or just wait until you get back to a wifi-enabled base.

There may be the odd use case where the Karoo struggles with something a competitor can do. In Wahoo world, if you’re out of mobile coverage, you can use your phone to send an existing route to your ELEMNT. But these feel few and far between.

So I’m fine with the Hammerhead approach. Your kilometerage may of course vary.

Battery life

If a device can go a few rides between charges, with ‘a few’ being very loosely defined, then it’s good enough for me. I struggle to find the topic of battery life interesting. Then I get grief, albeit from a subset of voltage ticklers, for not engaging with the subject.

So I did a science. A steaming great maths science on your YouTube doormat.

Hammerhead Karoo 2 battery life 3

What I Did

In my two test periods, each one starting with a fully charged battery, I used the Karoo 2 for rides of varying lengths and recorded the battery level over time. Or rather the Karoo did, in each FIT file, and I downloaded and anal-ysed them.

I didn’t do anything special to either use up or eke out battery life. I just used the Karoo without thinking. My standard protocol for life.

Hammerhead Karoo 2 battery life 1

What I Found Out

Long story short, in test period one, over 5 hours of riding, battery level reduced from 98% to 37%, a drop of 61 percentage points. Scaling that up implies that a fully charged Karoo 2 should give just over 8 hours of riding. Test 2 was similar, giving an implied 8.5 hours of real world battery life.

Hammerhead Karoo 2 battery life 2

Here endeth my doctoral thesis.

Eight hours is more than enough for my day-to-day velo, with the occasional ride at the weekend. But my bum would begin to squeak, high pitched and siren-like, if I was looking at a tough 100-miler or a big day in the mountains. There’s not much margin for error.

There is a battery saving mode, which I assume gets you closer to the upper end of the 7 – 14 hour battery life range that Hammerhead states for the Karoo 2, but be aware that in normal mode, it’ll require more frequent charges than competing Garmin and Wahoo bike computers.


Whilst we’re talking milliamp hours, my specialist subject, a very brief word on charging.

The Karoo 2 has a USB-C charging port, which appears to be the minimum requirement these days. Even Garmin is starting to get rid of the old-fashioned, slow to charge micro-USB power sphincter. So that’s all good.

Hammerhead Karoo 2 charging port

Less good is this detachable charging port cover. And I mean fully detachable.

Without the usual rubber banjo string keep-attached thingummy, surely this will get lost at some point.

But it hasn’t gone yet. So maybe Hammerhead know something about banjo strings.

Hammerhead says the port is waterproof so, once again, I’m probably wittering on about inconsequentialities.

Is The Hammerhead Karoo 2 A Good Bike Computer

You’ve probably guessed the answer. Yes.

I have very much enjoyed using the Karoo 2. I’m slightly confused why it took me so long to get it out of the box.

Having read earlier reviews, I was expecting issues with stability, features randomly not working, sensors dropping out. I’ve had none of this. Performance is as consistent as my Swiss clockwork bowels.

Hammerhead Karoo 2 end view

I did somehow, via a combination of persistent random button presses, i.e. my own fault, cause it to factory reset, but pleasingly, everything rebooted and resynced to my account without losing the custom screens I’d set up and historical ride data.

The Karoo 2 has everything I need from a bike computer, with a fantastic screen and a very usable software interface. As I think I’ve gushed enough, I love the automatic CLIMBER feature.

Hammerhead Karoo 2 turn directions

A note of caution. If you’re a posho with high end Shimano electronic gear wizardry, you should be aware that the Karoo 2 doesn’t have the usual Di2 integrations you see on high end Edges and Wahoos. It used to, but then SRAM bought Hammerhead, smokey decisions were made in knee jerk rooms, and now it doesn’t.

So only buy the Karoo 2 if you can live with not seeing what gear you’re in at all times (or if you’re prepared to install a third party app to the Karoo 2 that fixes the issue).

But with that disclaimer disclaimed, if:

  • you’re in the market for a premium bike computer with a display to tickle your eye buds;
  • you’re not in a monogamous relationship with either Garmin or Wahoo; and
  • you don’t want another bloody app on your smartphone (harrrumph!)

Then the Karoo 2 might be the handlebar dangler for you.

En garde!

PS. If you want to see how the Karoo 2 stacks up against its competitors, you might like to read my post comparing the best value touchscreen bike computers available right now.

Monty - Sportive Cyclist
Monty is an enthusiastic road cyclist with only moderate talent. He started Sportive Cyclist in 2013 to record the journey to his first 100 mile ride, the RideLondon 100. Over time the blog has expanded to include training advice, gear reviews and road cycling tales, all from the perspective of a not-very-fit MAMIL. Since you're here, Monty would also like you to check out his YouTube channel. Also, Monty really needs to stop referring to himself in the third person.

8 thoughts on “My Hammerhead Karoo 2 Review: Why Did I Wait So Long…?”

  1. The Garmin mount was designed for watch sized devices and fails often as the devices have grown.
    Use of a tether is essential.
    K2 battery issue is nullified by the external power pack everyone needs this days for boosting, anyway.
    and everyone not a neanderthal luddite carries a cellphone. Even me.
    All bike computers have issues. K2 is my favorite, though, until a phone with ANT+ gets it together.

  2. Garmin products are stone age era… Thier interface is 10 years outdated and the whole user experience it´s for a Neanderthal (at least) ….
    Others didn´t have touchscreens!!!
    500 for a Garmin it´s a steal ….

  3. I love my K2 and ride outside year round. The issue with the battery life, at least for me, becomes real during the winter. Like any battery, it doesn’t perform as well in cold temps (think 20-30F). It drops around 30-35% an hour at those temps.

  4. Nice review, I also love my Karoo! Battery life hasn’t been any issue for me at all, getting close to 10 hours of riding before having to charge. And about that rubber charge port cover – Hammerhead are now shipping the Karoo 2 with a cover that’s fit to the system so you can’t lose it! You can also buy it separately if you’d like to add it on an older unit that shipped without it!

  5. Nice review, yeah I love my Karoo 2 and the CLIMBER. The elevation data is pretty flaky in Australia, but that’s the NASA (?) data, not Hammerhead. My only gripe is it’s inability to load a route when you’re partway through the route. My other only gripe is its flattery with absurdly exaggerated ride data – way beyond that my previous cheapie XOSS G+ measured much more accurately and the route data for the ride. Hammerhead does listen and my Karoo, bought a couple of months ago, has a larger charging port cover that is tethered to the unit. That was one thing that every review knocked.

  6. How about using this as a graveller?

    Several of the reviews I read suggest that the K2 is wonderful for roadworks but that segmented trails, fire roads, and especially single track trails are poorly represented.

    Was that true of early versions or will I have still have (great?) difficulty in New England using this as a gravel explorer?


  7. Nice review adorned with flowery language.
    Having said that, you did not address the elephant in the room: the Karoo2 is less than half the price of an equivalent Garmin product. Unless money is no object to you at all, this is an overwhelming advantage over the evil Garmin monopoly, who think they can get away with abysmal customer service (at least in France). I returned my defective, back to the 90’s Garmin 530 and bought the Karoo for the exact same money and I could not be happier with my decision.


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