Originally Posted by
John E
Personal experience: my 1981/2 Bianchi takes 700Cx28 Continentals, but these tires run a couple of mm narrower than their callout size and measure about 25.5mm in both width and height above the rim. In contrast, I was not able to put 700Cx28 Specialized Armadillos, which run true to size or even a mm wider, on this bike, but they worked well on my Peugeot PKN-10 of about the same vintage.
I hope this helps. You just want to go to 25mm, so I do not think there is a problem with most brands of tires -- definitely not with Contis.
I've got an '87 Bianchi Nuovo Alloro so i imagine that the clearance would most likely be very similar to yours. how do the 28mm tires run on your bike? I've heard that sometimes with these older frames and how their geometry differs from modern frames that it can have a big effect on their overall performance/handling.