Seiko Spare Part – Third Wheel for Seiko 90 Stopwatch (Cal. 9011 Family), Ø approx. 11.7 mm (1 piece) – NOS

Original Seiko spare part – Third Wheel (三番車) from new old stock (NOS) for the Seiko "90" stopwatch (caliber family 9011). A single piece is offered in the original Seiko part bag.

Outer diameter: approx. 11.7 mm – an unusually large measurement for a wristwatch movement, which fits well with the large-format stopwatch movement. The third wheel is a component of the going train and transmits power between the center wheel and the second wheel; it shows the typical spoked form with a pinion.

Assignment: The original bag is labeled with "三番車" (Third Wheel) and "90" – the latter refers in this collection to the Seiko 90 stopwatch (Cal. 9011), a sought-after mechanical vintage stopwatch. Original going train parts for it are difficult to obtain today – particularly relevant for watchmakers and collectors who restore these stopwatches.

Note on assignment: The assignment is based on the handwritten "90" identification and the matching diameter, not on a printed part number. Please compare the diameter, tooth count, pinion, and height dimensions with the required wheel before installation.

The part is unused; due to storage, only minor, purely visual traces are possible, which do not impair the function.

Manufacturer: Seiko (K. Hattori & Co., Japan).

Warranty (used) This is an original part (NOS) stored for decades. The limitation period for claims for defects (statutory warranty) is 12 months from delivery.

Note Before installation, please compare the diameter, tooth count, pinion, and height dimensions, as well as the fit, with the required wheel; assembly should be carried out professionally.