A tachymeter bezel is a fixed bezel scale used in conjunction with a chronograph to calculate speed over a known distance. The scale is calibrated to measure the number of units — typically kilometres or miles — completed in one hour, based on the time taken to cover one unit. To use it: start the chronograph when passing a distance marker, stop it one unit later, and read the speed directly from where the seconds hand points on the tachymeter scale. The tachymeter is one of the oldest chronograph complications and one of the most recognisable bezel designs in watchmaking.
In replica watches, tachymeter bezel quality is assessed by the accuracy and legibility of the scale markings. The graduation lines, numerals, and scale divisions must be correctly spaced, correctly sized, and cleanly printed or engraved. At high-end grade, tachymeter markings are sharp, correctly proportioned, and consistent in weight across the full scale. At lower grades, soft printing, incorrect numeral spacing, and inconsistent line weight are common — details that become apparent when the bezel is examined closely against a reference photo.
In Practice
- Scale marking sharpness is the primary quality indicator. Tachymeter numerals and graduation lines should have clean, defined edges — not soft, not bleeding into the bezel surface. Soft markings indicate either low-resolution printing or insufficient ink depth, and are visible in any close QC photo of the bezel surface.
- Numeral spacing follows a logarithmic progression — the gaps between numbers are not equal. At the high end of the scale, numbers are closely spaced; at the low end, they spread further apart. Incorrect spacing at any point on the scale indicates the scale was not produced to the reference geometry.
- Bezel material varies by reference. Tachymeter bezels appear in steel, ceramic, carbon fiber, and PVD-coated variants. The base material affects both the appearance of the markings and their long-term durability — printed markings on a steel bezel wear differently than those applied to a ceramic surface.
- Tachymeter bezels are fixed — they do not rotate. The bezel should sit firmly against the case with no movement under finger pressure. A tachymeter bezel with any rotational play is not correctly secured, and the scale cannot be read accurately if the bezel position shifts during use.
- Alignment between the tachymeter scale and the chronograph seconds hand at rest is a precision indicator. On references where the seconds hand parks at 12 o'clock, the hand should point to the correct position on the tachymeter scale when at rest. A bezel that is seated even slightly off-center produces a misalignment between the scale and the hand that is visible in straight-on QC photos.
Related Terms
Bezel · Fixed Bezel · Ceramic Bezel · Dial · Indices · Case Size
Read Next
For a full overview of bezel types, materials, and how to evaluate bezel quality in QC photos — read: Replica Watch Bezel Guide