Citizen (Miyota) · Miyota 9075 GMT

Lorier Hyperion, Baltic Aquascaphe GMT and Bulova Wilton GMT power reserve: inside the Miyota 9075

The Lorier Hyperion and Hydra, the Baltic Aquascaphe GMT MK-II, the Boldr Odyssey Freediver GMT and the Bulova Classic Wilton GMT all run on the Miyota 9075, an affordable true GMT. From a full wind it lasts about 42 hours, a little under two days.

Updated September 2026 · Based on manufacturer specs, published reviews and watchmaker/owner reports

Watches that use the Miyota 9075

Before the 9075, a "true" GMT, where you jump the local hour hand when you land and leave the 24-hour hand on home time, was mostly the preserve of Rolex, Tudor, Grand Seiko and other in-house makers. Since it arrived in 2022, it has become the default movement for microbrand travel watches under about $1,000. It's a 9-series movement, built on the same platform as the Miyota 9015.

Specs at a glance

History and where it came from

Miyota, Citizen's movement maker, launched the 9015 in 2009 and spent the next decade supplying it to microbrands. What those brands couldn't buy was a traveller's GMT. The Swiss options available to independents were "caller" or "office" GMTs, where the extra hand moves in hour steps and the local hour hand stays put. That's fine for tracking a colleague's time zone, but awkward when you're the one travelling.

The 9075 changed that. aBlogtoWatch and Time+Tide both date its introduction to 2022, and aBlogtoWatch notes it's only about a millimetre thicker than the non-GMT 9-series calibers, at 4.92 mm. Monochrome's teardown shows the extra work sits in a multi-part hour wheel unit and a 24-hour wheel beside it, which let the local hour hand jump in either direction while the date follows it forwards or backwards.

Brands moved quickly. Nodus, RZE, Zelos, Boldr and Jack Mason were among the early users, Bulova put it in the Classic Wilton GMT, and Lorier moved the Hyperion and Hydra to it in 2023. Baltic switched its Aquascaphe GMT from a Soprod caller movement to the 9075 for the MK-II in 2026.

Accuracy in the real world

Miyota rates the 9075 at -10 to +30 seconds a day, the same as the 9015. Owner reports collected by Caliber Corner range from about +2 to +15 seconds a day, with some watches needing adjustment and others holding steady inside spec. That's broadly what you'd expect from an unregulated 4 Hz movement.

The GMT function doesn't add a timekeeping penalty in itself, but there's more going on under the dial than in a 9039, and the hour hand's jumper has to hold the hand crisply. aBlogtoWatch described the hour hand's click as crisp in both directions. If your Hyperion or Aquascaphe GMT gains more than the spec allows, magnetism is worth ruling out; Caliber Corner notes the 9075 isn't magnetically resistant.

Reliability and servicing

The 9075 is newer than the 9015 and doesn't yet have the same long track record, but it's built on a platform with a good reputation, and there are no widespread reports of a systemic fault.

• Brand service first. Caliber Corner notes replacement movements are scarcer than for the 9015 or NH35, so the cheap "swap the movement" route is less of a given. Go back to the brand if something goes wrong under warranty.
• Independent service. It's a conventional Miyota layout, and a competent watchmaker can service it. The hour wheel unit adds parts and care during reassembly.
• Modding. Parts availability for modders is limited compared with Seiko's NH-series.

Quirks worth knowing

• Setting the local time. In the first crown position, the local hour hand jumps in one-hour steps without stopping the watch. The date follows it forwards and backwards across midnight. That's the whole point of a true GMT.
• Setting the GMT hand. You set home time in the hacking position by moving all the hands together, then jump the local hour hand. Get the order right and it takes seconds.
• Thickness. At 4.92 mm it adds about a millimetre over a 9039. Lorier's Hyperion grew slightly for that reason.
• Rotor noise. Like the rest of the 9-series, the rotor winds one way and freewheels the other, and you may hear it.
• Winding from stopped. Caliber Corner puts a full wind at about 40 crown turns.

How it compares

• Seiko NH34: the cheaper alternative. It's a caller GMT at 3 Hz, so the GMT hand jumps, not the local hour. Fine for tracking another zone, less convenient for travel.
• ETA 2893: the Swiss caller GMT many brands used before. A similar beat and reserve, but you adjust the GMT hand, not the local hour.
• Seiko 6R54: Seiko's own GMT in the Alpinist GMT and 1968 Diver's GMT, with a 72-hour reserve but a caller-style GMT hand.
• Rolex 3285 / Tudor MT5652: true GMTs with 70-hour reserves. The 9075 gives you the same travel-friendly layout at a fraction of the price, with less than two-thirds of the reserve.

Living with the 42-hour reserve

A GMT is a travel watch, and 42 hours is where the 9075 shows its price. Wear your Lorier Hyperion on the flight out, and it'll be fine. Leave it on the hotel nightstand while you wear something else for two days, and it'll have stopped, taking the home-time hand and date with it. At home the rule is the same as for any 9-series watch: take a Baltic Aquascaphe GMT off at 6pm on Friday and it will stop around lunchtime on Sunday.

Resetting a stopped GMT is more fiddly than a three-hander, because you've got local time, home time and the date to get right again. Watch Winder counts down the reserve for each watch you own and reminds you before it stops, so you can wear the Hyperion or give it a few dozen crown turns first. For a one-off check, use the "Will my watch stop?" calculator.

Verdict

The Miyota 9075 is the movement that made the affordable true GMT possible. It's slim for what it does, runs at 4 Hz, and the jumping local hour hand works the way travellers want. The trade-offs are an ordinary 42-hour reserve, an audible one-way rotor and fewer spare movements than the 9015. If you want a Rolex-style GMT layout in a watch like the Lorier Hyperion or Baltic Aquascaphe GMT MK-II, nothing else at the price does it.

FAQ

How long does a Lorier Hyperion run off the wrist?

About 42 hours from a full wind, the Miyota 9075's rated reserve. A partly wound watch will stop sooner.

Is the Baltic Aquascaphe GMT a true GMT?

The MK-II, launched in 2026 with the Miyota 9075, is a true GMT with a jumping local hour hand. The original 2020 Aquascaphe GMT used a Soprod caller GMT, where the 24-hour hand is the one you adjust.

Does the Bulova Wilton GMT hack?

Yes. The Miyota 9075 stops the seconds hand when you pull the crown to the time-setting position, and it can be hand-wound.

How accurate is the Boldr Odyssey Freediver GMT?

The Miyota 9075 is rated at -10 to +30 seconds a day. Owners commonly report somewhere around +2 to +15 seconds a day.

Why did my Lorier Hydra stop while I was travelling?

Its 9075 runs for about 42 hours, so two days off the wrist is usually enough to stop it. Wind it by the crown before you pack it as a spare.

Does the date follow the hour hand on the Miyota 9075?

Yes. When you jump the local hour hand past midnight in either direction, the date moves with it.

What's the difference between the Miyota 9075 and the Seiko NH34?

The 9075 is a true GMT at 4 Hz where you jump the local hour hand. The NH34 is a 3 Hz caller GMT where you jump the 24-hour hand instead.

Sources

• Miyota: Cal. 9075 Premium Automatic specifications
• aBlogtoWatch: The game-changing Miyota 9075 automatic GMT movement
• Monochrome: Deconstructing a Miyota 9075
• Caliber Corner: Miyota caliber 9075
• Monochrome: Baltic Aquascaphe GMT MK-II introduction

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 10 hours of wear fills the Miyota 9075 GMT. Desk days charge more slowly.
• Most automatics can also be wound by the crown. If yours has stopped, a few dozen turns gets it going before you put it on.
• Off the wrist it stops about 42 hours after it was last full. Stopped sooner?
• On a watch winder, start at about 650 turns per day, both directions. Winder settings for every movement.
• If it does stop, don't set the date between 9pm and 3am. Check if it's safe.

All Miyota movements

Never let it stop

Watch Winder counts down the reserve of every watch you own and reminds you before one stops. It already knows the Miyota 9075 GMT: type your watch's name and the reserve fills itself in.

Manufacturer's published figure. Real reserve varies with the watch's age and service; check your manual.