...My FAVORITE mix-up I remember seeing while I lived in Canada though was an ad for a bike that was posted at the University (UBC). While describing the bike they said it had 26 inch wheels and an 80 cm frame (might have those numbers wrong). ?????? I stood there wondering what the heck bolts were on the thing...
The wheel size issue is worldwide. It really doesn't matter exactly what the wheel diameters are, as long as wheel and tire interchangeability is understood. As a result, nominal wheel sizes for cars and trucks are still in inches everywhere, while the rest of the tire dimensions are in metric units - thus, 205/75R14 tires
on my trailer (205 mm wide, 14 inch wheel/bead seat diameter).
The bolts on the bike are likely all metric.
The U.S. has its own strange mixing of units. Cars, for instance, are now entirely metric (unless there are still inch-sized fasteners in those engines derived from 1950 designs), and have been going that way for at least 30 years... but of course the speedometers are in miles per hour. Like the hundredweight reference, the measurement system used gives one a bit of a hint about the history of the machine.