Hammerhead Karoo 3: The Android Bike Computer, Reviewed After 4,000 km

Hammerhead's third-generation Karoo is the most capable bike computer on the market by most metrics 鈥?and the most polarizing. After 4,000 km in rain, snow, sun, and dust, I have a strong opinion on whether it's worth the $499 price tag.

What it does better than anyone

The screen. 3.4 inches, 800 nits peak brightness, fully readable in direct sunlight at noon. Garmin's flagship Edge 1050 hits 1,000 nits but is bigger and heavier. Wahoo's Roam V2 is dimmer. If you ride in bright conditions often, the Karoo wins on this metric alone.

The route planning. Hammerhead's companion app lets you draw a route by tapping a map, drag waypoints, and preview the elevation profile live. It's the fastest route-planning workflow of any bike computer ecosystem. Garmin Connect is clunky. Wahoo's app is barely functional. Hammerhead is the first bike computer that feels designed around route planning rather than around data display.

The maps. OSM-based, fully offline-capable, with detailed trail networks for gravel and mountain biking. The Karoo is the first bike computer I'd actually take bikepacking, because the offline maps include hiking trails, fire roads, and singletrack that Garmin's basemap ignores.

What it does worse than anyone

Battery life. Hammerhead claims 15 hours. In real-world mixed-use with the screen at 60% brightness, GPS at 1 Hz, and Bluetooth/ANT+ broadcasting, I averaged 12 hours. That's enough for most rides but tight for a 200 km brevet or 12-hour gravel race. The Edge 1040 Solar does better.

Workout / training view. If you're a structured-training person who lives in workout mode, the Karoo is serviceable but not as polished as Garmin's Edge ecosystem. Workout upload from TrainingPeaks works, but the on-device interval display is more basic than the Edge.

Button operation. The Karoo has one button (power) and uses the touchscreen for everything else. Garmin's Edge 1040 has 7 physical buttons, which matter when wearing thick gloves in winter or riding through heavy rain. Touchscreen-only is a non-starter for some riders.

The verdict

The Karoo 3 is the best bike computer for riders who: ride in mixed terrain (road + gravel), live in bright climates, value offline maps, and prioritize route planning over structured training. For pure road racers who live in workout mode and want maximum battery, the Garmin Edge 1040 Solar remains a better choice.

Recommended with caveats. Make sure you can live with the touchscreen-only interface and the slightly tighter battery life.