# Hammerhead Karoo 3 vs Sigma ROX 12.1 Evo: specs and price compared

A sourced, side-by-side comparison of the Hammerhead Karoo 3 (Hammerhead) and Sigma ROX 12.1 Evo (Sigma) among bike computers. Sigma ROX 12.1 Evo is the cheaper of the two at $379.95.

## Side by side

| Spec | Hammerhead Karoo 3 | Sigma ROX 12.1 Evo |
| --- | --- | --- |
| US price | $524.99 | $379.95 |
| Brand | Hammerhead | Sigma |
| Released | 2024-05 | 2023-06 |
| Display size (in) | 3.2 in | 3.0 in |
| Touchscreen | Yes | Yes |
| Battery life hours | 15 | 14 |
| Preloaded maps | Yes | Yes |
| Multiband gnss | Yes | No |
| Connectivity | ANT+, Bluetooth, Wi-Fi | ANT+, Bluetooth, Wi-Fi |
| Weight (g) | 118 | 112 |

## Key differences

- Display size (in): Hammerhead Karoo 3 3.2 in vs Sigma ROX 12.1 Evo 3.0 in
- Battery life hours: Hammerhead Karoo 3 15 vs Sigma ROX 12.1 Evo 14
- Multiband gnss: Hammerhead Karoo 3 Yes vs Sigma ROX 12.1 Evo No
- Weight (g): Hammerhead Karoo 3 118 vs Sigma ROX 12.1 Evo 112

## What reviewers say

**Hammerhead Karoo 3** — Both whitelisted testers reviewed the Karoo 3. DC Rainmaker ran multi-month, side-by-side testing against the Garmin Edge 840 and Wahoo ROAM V2 (GPS/elevation data plots, battery-burn charts). Cycling Weekly did a hands-on but qualitative test on a Morocco ride, with no measured metrics. Both praise navigation and user-friendliness and call it a legitimate Garmin/Wahoo rival. Both note it is not meaningfully faster / slow to power up despite the new processor and RAM. On battery they diverge: Cycling Weekly found the 15+hr claim falls short in real use, while DC Rainmaker found the claimed ~30% improvement roughly holds (about 12-13hr realistic). No RTINGS or lab-benchmark source exists for this model. (2 sourced reviews.)

**Sigma ROX 12.1 Evo** — Only one whitelisted tester (BikeRadar) published a hands-on review of this exact model. BikeRadar rated it 2/5, praising easy route-following and rich training data but panning meagre battery life (10h with a heart rate monitor only; 4.5h navigating with sensors), a rain-triggered touchscreen, cheap build and an uncompetitive £379.95 price. (1 sourced review.)

## Sources

- Hammerhead Karoo 3: https://shop.sram.com/collections/cockpit-and-controls/products/karoo (shop.sram.com, verified 2026-06-19)
- Sigma ROX 12.1 Evo: https://sigma.bike/product/rox-12-1-evo/ (sigma.bike, verified 2026-06-19)

Canonical: https://frontdeskreview.com/gear/bike-computers/hammerhead-karoo-3-vs-sigma-rox-12-1-evo/
Cite: Per The Front Desk Review, Hammerhead Karoo 3 ($524.99) vs Sigma ROX 12.1 Evo ($379.95) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/bike-computers/hammerhead-karoo-3-vs-sigma-rox-12-1-evo/
License: CC BY 4.0.