I need some 5 ray rims but the ones I find on the internet are way too expensive, so I decided to "roll my own" by creating a 3D model and having it machined from a piece of aluminum.
I've chosen to go with 20x2.125, or roughly 500mm in diameter and 50mm in width, tires for my rim. I'm looking at the nominal section widths of the standard and for this size tire I see that a size of
21C, 23C, 25C rim is required. Nowhere is mentioned what
C stands for tho. I assume it's from
crotched but I'd like a word of comfort on that. So basically this means that my rim's inner width (the one labeled 19 here) must be between 21 and 25 millimeters?