Originally Posted by
Andrew R Stewart
It would be interesting to have an actual width measurement of the OP's 25 tire and then of the current 23 one that he is looking at. He might find that they are not 2mm different in width.
When I first started riding in the mid-80's the most common 700c road tires sizes were 700-20, 700-25 and 700-28, or so the sidewall labels read. I measured the "700-25" tires on my first 700c bike at about 23 mm in actual width on normal road rims. A few years later tires labeled 700-23 started to become the norm and most I had measured a true 23 mm as installed and current ones still do. I think that 700-23 is the old 700-25 subject to "truth in advertising".