I guess it's the bike industry equivalent of measuring a 2 x 4.
Ahh, but a 2x4 actually measures 2x4", even though your tape measure continues to give you a 1½ x 3½" every time!
Dimensions on lumber are based upon their green size. As wood dries, it shrinks, so when manufacturing dry lumber, it's planed to the dry equivalent of what an average wet 2x4 would shrink down to (rounded off a bit).
Makes sense though that the tire used would affect the folded size of the bike. I think it's a pretty nice idea to have one. Would beat throwing my old clunker onto the bike rack hanging off the back of my car. Much easier to just chuck it in the back.
Actually, I think lumber is rough-sawn to the 2x4 dimension. But once you plane it smooth, it obviously shrinks. I've lived in a couple of late 1800's houses that were made of rough-sawn studs. They really were 2x4.
Doesn't have so much to do with moisture content, but the difference between rough and smooth sawn lumber.
Yes, rough sawn lumber is cut to 2x4", but the wood shrinks a lot when dried. My brain wasn't working quite right yesterday, as I kept thinking that 2x4 was 1-3/4 x 3-3/4" planed. Which is correct for green planed lumber. Wood planed at that dimension will drop in size to 1½ x 3½ when dried. So the difference is half dryness & half surfacing.
I used to own a mill where we dried lumber. You would put a bundle in of green wood with the steel straps on as tight as you could put them. You had to be careful when taking the lumber out as the straps could be pulled off the bundles after drying.
We had a claim once because we planed some wood that was too wet (about 30% moisture content) and when it air dried it was under-dimension and couldn't be used. We had to remove all our grade stamps off of every piece. Not fun. I don't miss those days. Those days you look up at the sky and say to yourself, "I'd rather be hiking".
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