Originally Posted by
FBinNY
If you sketch the possibilities, you'll see that you reach maximum height when the rim inside width approaches the tire's outside width. Narrower than that, it's as I described, and wider than that your scenario applies.
Yeah, I did some back-of-the envelope sketches and calculations. Here is where I think my mistake arose. The same tire on a wider rim is, as you say, wider and taller. BUT more of the circle roughly defined by the tire is below the top of the rim (imaginary). Not enough to shorten the tire relative to mounting it on a narrower rim, but enough to change the aspect ratio. So it resembles a taller, wider tire that is buried a bit more down in the rim. So it is taller but RELATIVELY shorter compared to width. I guess that explains the source of the widely promoted benefits. Does this make any sense?