TUDOR Black Bay Chrono M79360N-0011: specifications and checks

Two pushers that have to be unlocked first

TUDOR specifies stainless steel screw-down pushers at 2 o'clock and 4 o'clock, alongside a screw-down winding crown.

So there are three threaded penetrations of this case, and two of them must be released before the chronograph does anything at all.

That catches people out in both directions.

A dealer who presses a screwed-down pusher gets no response and concludes the chronograph is dead. Worse, one who presses harder is loading a pusher against its own thread, which is how tubes get damaged.

And a buyer who has never owned a screw-down chronograph will do exactly the same thing on their first evening.

So: unscrew the crown, unscrew both pushers, then test. Demonstrate the sequence at handover, and say it in the listing.

Afterwards, screw all three back down and confirm each sits flush. The 200 metre rating rests on all of them.

Test it under load, not with a click

Start, stop, reset proves the pushers move. It proves very little else.

A running chronograph draws power from the movement. Where amplitude has dropped away, the watch will look fine left alone and then fall behind as soon as the counters are put to work — a failure that only shows up over hours.

So start it, leave it running for a few hours while you do something else, and compare against a reference clock. The Manufacture Calibre MT5813 is COSC certified with approximately 70 hours of reserve, so it has the capacity for a long test.

Then reset, and look closely: the chronograph seconds hand must return to exactly zero. A hand that stops a fraction short or long is the commonest chronograph fault there is, it is visible without tools, and it is a genuine bench job rather than an adjustment.

Check the date at 6 o'clock changes cleanly across midnight while you are at it.

A tachymeter on aluminium

The bezel is fixed stainless steel with a matt black anodised aluminium disc carrying a tachymetric scale and silver markings.

Two things there.

Fixed — it does not turn. Do not try to turn it, and do not describe it as rotating.

Anodised aluminium — it fades and dents rather than chipping, so a slightly dulled disc on a used example is ageing rather than damage. What to look for instead is uneven fading across sectors, dents around the edge, and whether the silver markings are complete and legible all the way round the scale. Worn markings on a tachymeter make the scale unusable, which is the whole point of the bezel.

The bracelet and clasp

A 3-link stainless steel rivet-style bracelet with polished and satin-brushed finishes, closed by a TUDOR T-fit rapid adjustment clasp.

The rivet styling puts raised detail on the outer links, which is where wear concentrates — run a thumbnail along them and look under a loupe for flattening. Polished centre sections on a three-link bracelet are the other wear point, since they show every mark.

Then work the T-fit through every position. It is toolless, it is used daily, and it should lock positively at each step rather than sliding under a pull.

Case and crystal: 41mm steel, polished and satin-brushed, with a domed sapphire over a black dial with silver counters. Tilt the watch and check the crystal's edge for chips, which is how sapphire fails.