MovementSwap

Different footprints. The Seiko 7S26 is 27.40 mm x 4.90 mm and the Miyota 9075 is 26.00 mm x 4.92 mm, so they do not share a case. This is a choice between platforms, not a swap. Published dimensions, layout and the checks before you swap one for the other.

Updated 05 September 2026.

Drop-in resolution

Seiko 7S26 vs Miyota 9075: do they swap?

Whether the Seiko 7S26 and Miyota 9075 share a case, and what changes if you move between them.

No drop-in

Different footprints. The Seiko 7S26 is 27.40 mm x 4.90 mm and the Miyota 9075 is 26.00 mm x 4.92 mm, so they do not share a case. This is a choice between platforms, not a swap.

The Seiko 7S26 is the long-running Seiko workhorse behind the SKX and Seiko 5, day-date, non-hacking. The Miyota 9075 is the Miyota true-GMT (traveller) automatic, in affordable GMT travel watches.

They differ in diameter (27.40 mm vs 26.00 mm), beat rate (21,600 A/h (3 Hz) vs 28,800 A/h (4 Hz)), calendar layout (centre seconds, day and date at 3 vs centre seconds, true GMT 24h hand, date at 3), winding behaviour. The predecessor of the NH36 at 27.40 mm x 4.90 mm, without hand-winding or hacking. It shares the 27.40 mm case fit of the NH3x family, so an NH36 is the standard upgrade donor into a 7S26 case.

Matching diameter and height is necessary but not sufficient. A donor is only a true drop-in when the dial-foot positions, hand-hole sizes, stem length and calendar layout also match. Two movements can share a case and still need a new dial, re-broached hands or a cut-to-length stem.

Calibers and lookups

Seiko 7S2627.40 mm x 4.90 mm
Miyota 907526.00 mm x 4.92 mm
Donor movement for Seiko 7S26drop-in lookup
Donor movement for Miyota 9075drop-in lookup

Questions and answers

Seiko 7S26 vs Miyota 9075: do they swap?

Different footprints. The Seiko 7S26 is 27.40 mm x 4.90 mm and the Miyota 9075 is 26.00 mm x 4.92 mm, so they do not share a case. This is a choice between platforms, not a swap.