Hammerhead's "New" Karoo 3 - what I like, what I don't

Show up to any cyclocross race or group gravel ride and you're going to see a ton of handlebar-mounted GPS cyclecomputers from Garmin and Wahoo; but there's a 3rd option - Hammerhead's Karoo, an Android-based device, that you don't see nearly as often. That could be changing with the recent release of the new Hammerhead Karoo, their first release since being acquired by industry giant SRAM. 

Hammerhead calls the "3rd" revision of the Karoo the "New Karoo", not the Karoo 3 -  just like the use of the labeling "new SRAM Red" to describe the latest revision to their top-end road racing group. I'll refer to it as the 3rd-generation Karoo for clarity. 

Who should consider the Karoo 3, and who should give it a pass? Let's take a look.

First device since SRAM acquisition

This is the first Karoo device released since SRAM acquired Hammerhead a bit less than 3 years ago. Hammerhead is now a business unit of SRAM, just like Zipp, Rockshox, Truvativ, Time pedals, and so on.

Since that time, wireless AXS shifting drivetrains have continued to expand across the SRAM line. As expected, the Karoo 3 has deep integration with the "bonus buttons" and blips that are part of SRAM's AXS shifting options. It's really a device targetted at riders who are already deep into the SRAM ecosystem, as we'll see from reviewing some of the features.

Karoo 3 is a high-end option

At $475, Karoo 3 is positioned as a high-end, premium option targetted at riders who use high-end component groups, carbon wheels, power meters...  you get the idea. Garmin's Edge 540 is one of the most popular devices by unit count, and carries an MSRP of $349.99 (and "on sale" at the moment for $299.99), while the touchscreen Edge 840 is $449.99 (also "on sale" for $399.99 currently.)

It's worth noting that Garmin devices are rarely discounted, until the next generation is on the horizon, which could suggest updated devices coming soon.

 Pros Cons
  • Excellent support for SRAM AXS users
  • More RAM, more storage, faster processor
  • Regular, consistent software updates - significantly more often than Garmin
  • USB-C charging port
  • Louder "beep" sounds
  • Gorilla Glass display
  • Able to sideload Android apps of your choice
  • Lack of features for Shimano Di2 users
  • Proprietary, non-standard mount (although an adapter to the "Garmin standard" is included)
  • Expensive, when compared with competiting devices
  • Removed SIM card option means some feaures now rely on the companion app on your phone being present

Karoo 3 has a beautiful, high-resolution screen

As someone currently using the Garmin ecosystem, the screen on the Karoo 3 blows away the Garmin Edge 500-series devices. There's nothing wrong with my Garmin screen - I can see it just fine. But after looking at the Karoo 3, they aren't in the same class.

The Karoo 3's 3.2", 480 x 800 pixel display isn't quite as high-res as your $1000 mobile phone, but is a huge improvement compared to the 2.6", 246 x 322 pixel display on a Garmin 500 series device. That might be ideal for older riders with poor eyesight, as well as riders who want to have many display fields (heart rate, power, zones, and so on) powered by many connected sensors. It's also got a new Gorilla Glass cover, for better durability.

There's also quite a bit more screen real estate for mapping or charts. Karoo 3 has a brighter display compared to the Karoo 2 also.

What else is new in the Karoo 3?

Like any new cellphone or laptop release, the latest version of the Karoo has more memory, more storage, faster processor, etc. Compared with the previous generation Karoo 2, the "New" Karoo 3 buyers get:

  • 64 GB of storage, for maps
  • Bigger capacity battery
  • 4 GB of RAM
  • Faster CPU
  • Claimed 30% increase in battery life due to a mix of software optimization and hardware improvements

One feature that goes away is the SIM card slot, it's no longer possible to get internet connected from the Karoo device alone, a mobile phone nearby is needed:

Companion app

The older Karoo 2 offered the option to install a mobile SIM card for data access, allowing you to upload a ride without your mobile phone present. On the Karoo 3, Hammerhead has switched to the Garmin model, relying on a companion app installed on your mobile phone for internet access. The assumption is you probably carry your phone everywhere, anyway, and I'm inclined to agree.

Sideloading Android apps onto the Karoo 3

If you currently live in the Android ecosystem (phone, watch, tablet) you might be interested to know that the Karoo 3 allows sideloading of Android apps - it as, after all, just another Android device itself.

So you can probably use streaming audio, like Pandora, and control it from the Karoo 3 head unit. Note that the Karoo 3 has no speaker, but Bluetooth headphones could be used. In a recent launch interview, it was noted that users have even installed Netflix! Reddit has a nice /Karoo subreddit that's pretty active if you want to see some real-world experiences users have with sideloading.

Designed primarily for SRAM users, not Shimano

The Karoo 3 becomes a more obvious choice for riders who are in the SRAM ecosystem. If you're already riding SRAM AXS wireless shifting, you already have an AXS "account" tied to your email address, which knows about all your bikes. Power up the Karoo 3, sign in, and it will already know about all your bikes and sensors - sisgnificantly speeding up the pairing and setup process.

Riding Shimano's Di2 electronic shifting? This may not be the best device for you. Hammerhead raised some eyebrows in May, 2022 when they announced changes to the Karoo's software, removing some Di2 features, including:

"...the update will remove on-screen battery status and shifter mode data, front and rear derailleur indications, and Karoo screen control via the Di2 hood buttons from Shimano Di2 drivetrains."

So what happened? Short story, Hammerhead was indepenently owned and worked fine with both SRAM and Shimano, Hammerhead then gets acquired by SRAM, upon which Shimano used licensing leverage to force Hammerhead to remove the Di2-specific functionality - presumably, because they didn't want to directly support their primary competitor for components by providing a software integration - a fancy way of saying, "sour grapes."

What's missing for Shimano Di2 users?

If you have a Shimano Di2-equipped bike and a Karoo 2/3, you will lose these features that are on Garmin / Wahoo devices:

  • Ability to see Di2 battery level
  • Ability to see the current gear you're in
  • Ability to control the cyclecomputer (such as switching display screens) via the hood buttons on Dura-Ace / Ultegra shifters

Shimano riders can continue to use the Karoo 2/3 for ride tracking, mapping, navigation, Strava, etc. - just no Di2 integration. Obviously, losing features on a paid for piece of hardware is a huge negative, and those bad memories will probably steer riders in the Shimano Di2 ecosystem to a Wahoo or Garmin device instead.

The excellent DC Rainmaker blog has a nice writeup on a "hack" to put Di2 support back on the Karoo 2, via sideloading an app (possible because the Karoo runs on the Android platform, like a mobile phone). It's great this exists, but users shouldn't have to do it in the first place. Not clear if the same will also be possible on the new Karoo 3, but it seems likely, given that Hammerhead has publicly touted the ability to "side load" apps on the new device.

Given the excellent support from other brands for Shimano Di2 shifting, the bottom line is that all but the most very motivated Shimano users will skip the Karoo 3 in favor of a Wahoo or Garmin GPS cyclecomputer instead.

Karoo 3 will be supplied as original equipment on some complete bikes

One of the more interesting announcements is that the new Karoo 3 will be coming as a stock piece of equipment on complete bikes. Obviously, a $475 cyclecomputer adds fairly significantly to the retail price of a new bike, so you're only likely to see this on very high-end options: think full carbon frames and wheels, SRAM Red AXS equipped, power meter included models.

Still, it's a nice indicator of what might be coming in the future as riders increasingly rely on their handlebar-mounted GPS computer to track Strava segments, control head and tail lights, operate rear-facing radar, and so on. With almost every high-end road and gravel bike now including a battery (or multiple batteries) for electronic shifting, it's only a matter of time until we get a GPS head unit, powered and charged by the battery that's already hidden in the seatpost.


This one is pretty easy. If you own SRAM AXS-equipped bikes, the Hammerhead Karoo 3 is worth a serious look. If you're riding SRAM or Shimano mechanical shifting bikes; or Shimano Di2 electronic shifting, the more popular Garmin and Wahoo devices probably make more sense for your needs.



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