The 2017 partnership
In 2017, Breitling and Tudor announced a movement-sharing partnership that surprised the watch world. Two competitors, both owned outside the major luxury groups, recognised they each had a gap. Tudor needed an in-house chronograph beyond the older ETA-base Heritage Chrono; Breitling had its 2009 B01 sitting unused outside the Breitling line. Breitling needed an in-house three-hand-date base for the Superocean Heritage and the Premier; Tudor had its MT5612 sitting at the Kenissi manufacture. They swapped: Breitling supplied B01 → Tudor (as MT5813), Tudor supplied MT5612 → Breitling (as B20).
What the B20 brings
The B20 is the MT5612 architecture with Breitling-specific finishing and regulation. Free-sprung balance with weighted-screw regulation (the Tudor signature). Silicon hairspring for non-magnetic operation. 70-hour power reserve, the modern Swiss benchmark. COSC chronometer certification. The base movement is manufactured at the Kenissi facility in Le Locle (jointly owned by Tudor and Chanel since 2019) and shipped to Breitling for finishing and casing. The "B20" designation is Breitling's internal numbering; mechanically and architecturally it is the MT5612.
Watches it powers
Breitling Superocean Heritage II 42 / 44 / 46 (B20 in the modern Heritage II line, replacing the older ETA-base Heritage). Premier Automatic 40 / 42 (some refs in the Premier dress-watch line). Top Time B20 in selected Top Time refs. The B20 specifically powers the three-hand-with-date Breitling line; the chronograph references in the Superocean Heritage / Premier lines run on the older B01 chronograph or on Valjoux 7750-base movements. Production volume is meaningful but smaller than the B01 chronograph.
Why it works for both brands
The partnership is unusual but commercially logical. Tudor and Breitling both target the CHF 4,000-7,000 Swiss-mechanical-with-real-engineering tier. By sharing movement architectures, both brands avoided duplicating engineering investment that smaller volumes would not justify. The Breitling Superocean Heritage II at CHF 4,500 with a B20 inside delivers in-house-class movement at sub-Rolex pricing; the Tudor Black Bay Chrono at CHF 5,400 with an MT5813 inside does the same on the chronograph side. Neither brand could have justified developing both architectures alone; together they cover both tiers.
Service notes
Service for a B20-equipped Breitling runs CHF 600-900 at Breitling, with the 2-year warranty. Recommended interval: 10 years, matching the modern Swiss benchmark made possible by the silicon hairspring (no magnetism worries) and modern oils. Independent service is technically possible; the silicon hairspring and free-sprung balance components require specialist tooling but most modern watchmakers can handle them. Parts access is restricted to Breitling-authorised channels for the architecture-specific components. The watch comes back regulated to -4/+6 sec/day COSC spec across all positions.