The term racing, in watchmaking, does not describe a single component but rather a coherent set of technical and formal choices born from direct contact between chronographs and motorsport, consolidated between the 1960s and 1970s. Anyone who has worked on those calibers recognizes it immediately: tachymetric scale on the bezel, mushroom-type pushers, shaped sub-dials, dial with orange or red accents. It is not borrowed aesthetics: it is a response to real circuit problems.
The tachymetric scale is the most technical element of the system. It is a graduation engraved on the fixed bezel or printed on the dial that allows you to derive the average speed of a vehicle over a known distance, usually one kilometer or mile, by directly reading the point where the chronograph's seconds hand stops. No calculation is needed: you start the chronograph at the beginning of the section, stop it at the finish, and read the scale. Some manufacturers, like Baltic on the Tricompax, have readapted the first quarter of the scale to cover the 60–75 seconds interval instead of 1–15, bringing the instrument closer to the speeds actually achievable in racing. This is a rare and honest modification.
Mushroom-type pushers have a domed, wide head. They were developed to be operated with racing gloves without losing precision. On the bench I recognize them even without looking: they have a different stroke than standard cylindrical pushers, softer at the engagement point. They characterize the aesthetics of many vintage sports chronographs and have been taken up in recent productions such as the Baltic x Peter Auto Tricompax.
The racing dial is a specific dial configuration: gray or black background with chronograph hands in orange or red, sometimes with bicolor accents. The Speedmaster Mark II ref. 145.014 is a documented reference, as is the 2004 Japan Racing ref. 3570.40 version. The shaped sub-dials, trapezoidal or oval like on the Yema Rallygraf, echo the dashboard instruments of race cars from the 1960s and 1970s.
British Racing Green deserves a separate note. It is the dark green traditionally used by British automobiles in competition, documented at least since the 1903 Gordon Bennett Cup. In contemporary watchmaking it has become a recurring color reference for sports dials, often achieved with PVD treatment on a guilloché base. The connection to motorsport is historical, not decorative.
Regarding the relationship between this design and perforated straps called rally straps: the technical connection exists and is documented — the perforations derive from automotive weight-reduction techniques — but that is a separate entry.