Originally Posted by
NomarsGirl
Isn't it great that we have more choices than ever? The C&V guys can run their 23 mm high pressure tires on their steel framed bikes to their heart's content. I am very happy with the 28 mm tires that came stock with my Ruby. She can definitely handle 32s and I think up to 35 (disk brakes). If I were more into gravel riding, I would definitely think about 32s, but I prefer smooth pavement.
A huge number of C&V road bikes can take 32 or 35mm tires. Tons of road bikes from the 60s, 70, and early 80s can handle 32mm tires. And even many of the late 80s models can handle 28mm tires. This is across quality from entry to mid to high level frames.
There are some higher level road frames in the late 80s thru 90s that are limited to 25s, for sure.
If riding gravel, I would definitely consider 40mm or more...but that stuff varies greatly depending on location.