29'er is a strange number...
but everything else comes in metric sizes... cranks, seatpost, stem, handlebar clamp, fork end width, screws (M5, M6).
Honestly I can live with inches and gallons, but Fahrenheit, pounds and ounces confuse me to no end. Inches get confusing when they become decimals... 0.5in is easy enough, but what the hell is 1.9in? 48mm that's what...
"700c" is the spec. 622mm rim size and whatever tyre fits on it. 700c x 23c (23mm) is roughly 700mm tall... 700c x 35c (35mm) is about 730mm