Is the term "crochet" trying to mean the same as "hooked bead" (HB)? If so it's a poor reference till all agree, where as hooked bead is far more descriptive to what's actually the shape that's in play. But like I said in so many words, every generation feels the need to re term the old so to claim it as the new way.
Here's the way I was taught. This is page 12-4 from Sutherlands 6th manual, (published 1995). Note in the French section the "C" (of 700x35C) is listed as the code, not a rim/tire bead design reference. IIRC the vast majority of rim designs when this lettered code was being created were of non hooked edge, steel folded and rolled being the common manufacturing process. When extruded Al rims began coming to market they followed this same tire/rim interface. I believe it was the mid 1970s when hooked edge rims became popular, among the performance riders first due to their looking for less weight of skinnier tires which required more pressure to keep the rim off the road. So as roads improved and riders could get away with narrower and higher pressure tires the rim diameters for equally diametered tires increased to maintain the tire frame fit.
Each manufacturer of rims/tires catered first to their OEM customers and secondarily to the repair/after market. As bike manufacturers began to export their bikes to other countries the issue of what tire fits what bike began to become more a problem and various attempts began to "standardize" both size markings as well as actual production. The ISO's ETRTO numbering system is the current attempt that has pretty much been adapted by most. Andy
