properties /measurement

The overall outer (or rim) diameter of a round or cylindrical product - the distance across a circular section through its centre. The general headline dimension of round housewares and goods: a bowl or pot by its rim diameter (a 30 cm bowl), a bin, a plate, a lid, a wheel, a pipe's bore. A numeral with a length unit (mm / cm / m / in). Product-intrinsic, distinct from SHIPPING/package dimensions (fulfilment). This is the PRODUCT'S OWN overall diameter - kind-specific part diameters (a microwave's turntable_diameter, a slicer's blade_diameter, a bearing's bore_diameter, a ball joint's stud_cone_diameter) remain separate facts of a named part, not this general one. Where a catalogue merchandises the same product across diameter variants, that is a downstream family statement, not a Pool fact. ON A BEARING IT IS THE OUTSIDE DIAMETER `D` AND NOTHING ELSE (b158). A bearing is two concentric circles and this slot holds one of them; SKF's table heads the pair `d` and `D` under `Principal dimensions` and prints 25 and 52 for the 6205, Koyo catalogues Habib's row 72 as `38 x 74 x 36/33`, and the aftermarket prints the same pair as `Inner diameter 55 mm` / `Outer diameter 90 mm` for SKF's VKBA 3552. The bore has its own slot, `bore_diameter`, on this definition's own named-part precedent - and the division was written into BOTH definitions rather than left to be inferred, because a grammar in which `38` and `74` are the same statement is a grammar that cannot sell a bearing. IT ALSO HOLDS AN ARC: a drum brake shoe or a loose drum lining is a crescent with no overall diameter of its own, and the diameter every maker publishes for it is the drum it is ground to run in - Brembo's own field name on its brake-shoe page is `Diameter` (S 83 531, `Diameter 200mm` beside `Width 37mm`) and Textar's is `inner brake drum diameter`, and the two agree part-for-part (Textar 84062500 = 200 mm, 91057400 = 203 mm, 91048400 = 185 mm). That is a dimension of the part in the hand and NOT a fitment [REFINE-LOG 2026-08-25]: it names no vehicle, and nothing about the arc changes when a model is discontinued - the same reading `thread_size` already gets.