Originally Posted by
Happy Feet
The problem with thinking modern 29r design was always around isn't regarding tire diameter, it's rim width. A modern 29r mtb tire won't fit a previously available 700c rim. Just like my 4.6" fat tires don't fit on standard 26r rims, even though they are nominally the same size.
Correct, a modern (as in 2020 model) tire wasn't around in 2006 or before. Modern 700c and modern 28" tires also weren't around then.
A tire size consists of rim diameter AND width. A rim size consists of diameter AND inner diameter. You seem to ignore the width part.
And there are recommended tire and rim width combinations. Of course, tires of very different width don't fit on the same rim.
I have 2" and 2.15" touring tires labelled as 28" and have them on my 29" labelled rims (marketed as MTB rims). They also fit on a wheel marketed as 700c I have. You also can buy a tire labelled as 29" and fit on all three rims.
The 4.6" fat tire doesn't fit on whatever you consider "standard" because of rim width, not because of diameter. I guess you could wrestle it on a 25mm rim if you really try.