The caliber 4R36 is one of Seiko’s workhouse movements. This is a technical review of the Seiko 5 Sports Ref. SRPD77 and the caliber 4R36 which powers it. Giving the break down is master watchmaker Jordan P. Ficklin, who explains if the movement rate can be improved on, and a way to straighten a misaligned chapter ring.
Produced by Jordan P. Ficklin.