Amazfit GTR 4 smartwatch review

Hot on the heels of the Amazfit GTR 3 Pro, the Hong Kong brand has launched its next-generation smartwatch line-up.

As before, there’s a tough, rugged model (the T-Rex Pro), plus sleeker and more stylish squared-off (GTS 4) and round-faced (GTR 4) designs. I opted to test the latter, for the fairest comparison with the GTR 3 Pro.

Amazfit GTR 4 smartwatch details and specifications

All the features I liked about the Amazfit GTR 3 Pro have been retained for the GTR 4. It’s still very reasonably priced, you can link it to your phone via Bluetooth to receive calls and notifications, and there’s a built-in music player and Alexa voice assistance.

The AMOLED touchscreen is fractionally smaller than before, at 1.43in. However, a stainless steel surround and anti-glare glass bezel make the watch slightly bigger overall, at 46mm. Combined with the matt-aluminium finish of the frame, it adds a touch of class.

I'm not so sure about the red detailing on the crown, designed to “echo sports cars”, but it’s easy enough to ignore.

The watch is also fully waterproof (to 5 ATM/50m, and I’ve tested it in the pool). Amazfit says it plans to add rudimentary real-time navigation (but not mapping), too, with a future software update, allowing you to import and follow .gpx route files.

The biggest change, though, is the introduction of Amazfit's new twin-LED ‘BioTracker 4.0 PPG’ optical biometric sensor, said to gather 33 per cent more data than the previous generation.

Heart rate, blood oxygen and stress levels can all be monitored around the clock, should you so wish. The watch will also track sleep quality (now including naps), menstrual cycles and other data.

Improved but imperfect firmware

The watch runs on a new Zepp OS 2.0 operating system, developed by Amazfit’s parent company Zepp Health (formerly Huami). This is a lot smoother than the original software and the touchscreen is more responsive, with improved haptic feedback.

There’s also plenty of customisation available, with three colour combinations to choose from, plus downloadable watch faces (200 ) and apps, and swappable straps.

The menu/widget system is largely unchanged, and still a little confusing, initially at least.

Impressive battery life and solid metrics

The battery life is excellent – Amazfit claims the new 475mAh cell will last for 14 days of normal usage, but that will depend on which features and functions you use.

Even with the display in ‘always on’ mode and frequent use of Bluetooth and GPS, I was able to get well over a week out of every two-hour charge.

As for its ‘sports watch’ functions, I never had an issue with the GPS receiver on the 3 Pro, but Amazfit says it’s been boosted further with new dual-band circularly polarised antenna tech – apparently a smartwatch first.

As before, it supports the five main satellite systems, and a sixth is set to be added, for pin-point positioning. I certainly didn’t struggle to get a lock.

Outdoor cycling is one of eight automatically-recognised ‘workouts’ (with more than 150 in total able to be toggled manually).

In contrast to the GTR 3, which wouldn’t always react when I started pedalling, I found the GTR 4 a little over-sensitive even on the lowest setting, with a brisk walk or a short trip in the car tricking it into thinking I was turning the cranks.

I’ve yet to find a cycling watch with accurate sleep tracking, and the GTR 4 is no exception, often mistaking lying awake in bed for light sleep.

Of all the data on offer, perhaps the most important metric for cycling is heart rate. Amazfit claims to have improved its sensor and HR-tracking algorithm to the point where the watch “almost reaches the level of heart-rate belts”.

Using the GTR 4 alongside a Garmin Edge 530 GPS unit with a chest strap, I was initially disappointed by the wide disparity between the devices, with heart-rate measurements differing by up to 18bpm.

During testing, it became clear the issue wasn’t so much inaccuracy on the part of the watch, but lag.

If I allowed my heart rate to settle and gave the GTR 4 some time to catch up, readings were consistent with the Garmin.

However, as soon as I started moving, the watch was several seconds slower to pick up on any heart-rate changes.

The higher the exertion, the longer it seemed to take to catch up – often well over 10 seconds. Once it finally did, though, readings were generally within /-2bpm.

If you’re seriously into your training and performance monitoring, and require heart-rate tracking that’s accurate to the nearest second, this could be a problem.

More casual users should be satisfied, though.

Amazfit GTR 4 smartwatch bottom line

The Amazfit GTR 4 is an impressive alternative to some of the best cycling smartwatches at a reasonable price.

The new biometric sensor provides a wealth of accurate data, the touchscreen user experience is of decent quality and it's a classy looking device.

If you can overlook the time lag in heart-rate tracking and lack of navigation, it's worthy of your consideration.