Tudor · Tudor MT5400

Tudor Black Bay 54, Pelagos 39 and Black Bay 58 power reserve: inside the MT5400

The Tudor Black Bay 54, Pelagos 39 and Ranger 36 run on the Manufacture Calibre MT5400, which lasts about 70 hours off the wrist, just under three days. The newest Black Bay 58s use the METAS-certified MT5400-U, rated at 65 hours.

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

Watches that use the MT5400

The MT5400 is the slightly larger twin of the MT5402 that powered the original Black Bay Fifty-Eight. Tudor first used it for Black Bay 58 models with display backs, where a bigger movement fills the window better. Since then it has become the engine of Tudor's smaller watches, and from 2025 a Master Chronometer version, the MT5400-U, has taken over the Black Bay 58 itself.

Steel black-gilt and navy Black Bay 58s made before the 2025 to 2026 update (references 79030N and 79030B) use the MT5402, not this movement.

Specs at a glance

History and where it came from

Tudor's in-house movement family began in 2015 and reached the Black Bay in 2016 as the MT5602. In 2018 Tudor made a smaller version, the MT5402, for the 39 mm Black Bay Fifty-Eight: 26 mm across and under 5 mm tall.

In 2021 Tudor released Black Bay 58s in 925 silver and 18K gold with sapphire casebacks. A 26 mm movement would have looked lost in the window, so Tudor enlarged it to about 30 mm and called it the MT5400. Caliber Corner and Monochrome both describe the size increase as cosmetic; the specs are unchanged. The Black Bay 58 Bronze from the same year got the MT5400 too, though its back is solid.

The MT5400 then spread. It went into the titanium Pelagos 39 in 2022, the 37 mm Black Bay 54 in 2023 and the 36 mm Ranger in 2025. In 2025 Tudor also launched the MT5400-U in the all-burgundy Black Bay 58, adding METAS Master Chronometer certification, and moved the black-gilt Black Bay 58 to it in 2026. The METAS version is quoted with a 65-hour reserve instead of 70.

Like its siblings, the MT5400 is a Tudor "Manufacture" calibre produced with Kenissi, the movement maker in which Tudor holds a stake.

Accuracy in the real world

Every MT5400 is COSC-certified. Tudor then checks the finished watch to -2/+4 seconds a day, a figure Monochrome repeats in its Pelagos 39 review. The MT5400-U goes further: METAS tests the complete watch in six positions, at two temperatures and at two levels of wind, to 0/+5 seconds a day, and checks it still runs accurately after exposure to 15,000 gauss.

Owners of the Black Bay 54 and Pelagos 39 on watch forums generally describe rates of a few seconds a day fast, within Tudor's window. The silicon hairspring means everyday magnetism is rarely a problem. As always, individual watches vary; if one runs well outside -2/+4 under warranty, it's worth a trip back to Tudor.

Reliability and servicing

The design is shared with the MT5402 and MT5602, which have been in service since 2018 and 2016 respectively, with no widely reported systemic faults. The transversal balance bridge supports the balance at both ends for better shock resistance.

• Warranty. Tudor's current guarantee lasts five years.
• Servicing. Tudor's network is the normal route. Parts for its manufacture calibres are harder for independents to get than ETA or Sellita parts.
• METAS watches. For an MT5400-U Black Bay 58, a Tudor service is the realistic way to keep it performing to its Master Chronometer rating.

Quirks worth knowing

• Two reserves, one name. A Black Bay 54 or Pelagos 39 is rated 70 hours; a 2025 or 2026 Black Bay 58 with the MT5400-U is rated 65 hours. The movement names differ by one letter.
• Mostly hidden. Despite being designed for display backs, most MT5400 watches, including the BB54, Pelagos 39 and steel BB58, have solid casebacks.
• No date. It's a true no-date movement, so there's no idle crown position.
• Filling it up. A long-reserve mainspring takes a while to wind fully. From stopped, give it plenty of crown turns rather than relying on the rotor over a quiet day.

How it compares

• Tudor MT5402: the same movement at 26 mm, in the original Black Bay 58 and Ranger 39. Same 70-hour spec.
• Tudor MT5602: the 41 mm Black Bay and Pelagos FXD movement: bigger, thicker, also 70 hours.
• Rolex 3230: the Submariner No Date and Explorer movement, 70 hours at 4 Hz, tested to -2/+2 cased.
• Omega 8800: Omega's Master Chronometer for the Seamaster 300M and Aqua Terra 38, with a co-axial escapement and 55 hours.
• Sellita SW200-1: the standard in most smaller vintage-style divers. Simpler to service, but around 38 to 41 hours.

Living with the 70-hour reserve

Seventy hours will take a Black Bay 54 or Pelagos 39 through a normal weekend. Take it off at 6pm on Friday after a full day's wear, and it will still be running at about 4pm on Monday. With the 65-hour MT5400-U, a Black Bay 58 taken off at the same time stops around 11am on Monday, so it's worth putting it back on before lunch.

A longer break is different. Wear a Pelagos 39 on holiday for a week and the Black Bay 54 at home will have stopped by midweek. Winding fully by the crown before you put a watch away gives you the whole reserve. Watch Winder counts down this 70-hour reserve for each watch you own and reminds you before it stops. To check a specific gap, try the "Will my watch stop?" calculator.

Verdict

The MT5400 is Tudor's best all-round small movement: slim enough for a 37 mm Black Bay 54, robust enough for a titanium Pelagos 39, and now good enough for METAS certification in the Black Bay 58. You get 70 hours (65 in the -U version), a silicon hairspring, COSC certification and Tudor's -2/+4 target. The compromises are the usual ones for a manufacture calibre: service goes through Tudor, and you rarely get to see it.

FAQ

How long does a Tudor Black Bay 54 run off the wrist?

About 70 hours, just under three days, from a full wind. If it wasn't fully wound when you took it off, it will stop sooner.

How long is the Tudor Pelagos 39 power reserve?

The Pelagos 39's MT5400 is rated at 70 hours. That's enough to leave it off from Friday evening to Monday afternoon.

Why does the new Tudor Black Bay 58 have 65 hours instead of 70?

The 2025 and 2026 Master Chronometer Black Bay 58s use the MT5400-U, which Tudor rates at a METAS-certified minimum of 65 hours. The older MT5402 Black Bay 58 was rated at 70 hours.

Does the Tudor Black Bay 54 hack?

Yes. The MT5400 stops the seconds hand when you pull out the crown, and it can be hand-wound.

How accurate is the Tudor Pelagos 39?

Its MT5400 is COSC-certified, and Tudor adjusts the finished watch to run within -2/+4 seconds a day.

Is the MT5400 the same as the MT5402?

Essentially yes, at a different size. The MT5400 is about 30 mm across against the MT5402's 26 mm, with the same 4 Hz beat, silicon spring and 70-hour reserve.

Sources

• Caliber Corner: Tudor Caliber MT5400
• Monochrome: Introducing the 37mm Tudor Black Bay 54 79000N
• Monochrome: Tudor Pelagos 39 titanium review
• Monochrome: Tudor Black Bay 58 Burgundy with METAS movement
• Monochrome: Tudor Ranger 36mm and Dune White dial (2025)

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 18 hours of wear fills the Tudor MT5400. 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 70 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 Tudor movements · Other 70-hour 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 Tudor MT5400: 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.