Galaxy Watch 4 turned into motorcycle sat nav with 3D-printed mount

At a glance:

• A Reddit user repurposed a Galaxy Watch 4 into a mini motorcycle sat nav by housing it in a 3D-printed shell with its charger.
• The charger's magnet base attaches the device to the bike, keeping the screen powered and active during rides.
• Lingering software issues include map lag and auto-rotate flipping the display at inopportune moments.

How a Galaxy Watch 4 became a motorcycle navigation screen

A Reddit user going by someones427 has demonstrated a surprisingly practical DIY project: turning an old Galaxy Watch 4 into a small satellite navigation display for a motorcycle. Shared on the Galaxy Watch subreddit, the build uses a 3D-printed enclosure to protect and stabilize the watch while it's mounted on the bike. The key hardware trick is leveraging the magnet base built into the Watch 4's charger — the same charger that keeps the device running — so the whole assembly can cling to any metal surface on the motorcycle without additional fasteners.

The result is an unobtrusive, round screen that sits naturally among the bike's instrument cluster. Unlike cars, which often have expansive dashboards perfect for Android Auto or large infotainment screens, motorcycles typically offer nothing more than a speedometer and tachometer. Aftermarket screens can clutter already-crowded handlebars, so a small, round wearable display arguably fits the aesthetic of many bike dashboards far better than a rectangular tablet bolted to the bars.

What still needs fixing

Despite the clever hardware setup, the project isn't fully polished. someones427 notes that the Galaxy Watch 4's map display can fall out of sync with the connected phone, introducing noticeable lag that makes real-time navigation unreliable. There's also an auto-rotate issue where the screen flips its orientation at the wrong moments, potentially disorienting the rider mid-ride. Keeping the charger plugged in solves the battery problem, but the software-side quirks mean the experience is currently more of a proof of concept than a turnkey product.

Commenters on the Reddit thread have already offered suggestions to address the lag and rotation problems, suggesting that with some software tweaks or a custom companion app the build could become genuinely usable. For now, the project sits in that satisfying middle ground — a fun, functional hack that clearly works but still has rough edges.

Why old wearables make interesting DIY projects

The Galaxy Watch 4 was released in 2021 and has since been succeeded by newer models, so plenty of units are likely sitting unused in drawers. Rather than letting them gather dust, creative makers have been finding second lives for them. A few months ago, another Reddit user turned a smartwatch into a gearshift indicator for a car, and this motorcycle sat nav project follows the same spirit — repurposing a small, always-on display into a vehicle accessory.

What makes the Galaxy Watch 4 a decent candidate for this kind of work is its round AMOLED screen, built-in GPS, and Bluetooth connectivity to a phone for map data. Combine that with a 3D printer and a handful of off-the-shelf components, and you have a low-cost alternative to expensive aftermarket motorcycle navigation units. The biggest limitation, as always with repurposed smartwatch hardware, is that the original OS wasn't designed for this use case, so workarounds are necessary.

What to watch next

If the software issues get resolved — whether through Samsung updates, third-party apps, or community-developed fixes — this could evolve into a repeatable project that other riders replicate. The magnet-charger mounting method is especially appealing because it requires no permanent modifications to the bike. For now, the project remains a neat proof of concept that shows how much functionality an old Galaxy Watch still packs, even years after its initial release.