I am trying to get as big tires as possible to my vintage road bikes. First I thought that my mid 80s Daccordi could take 30 mm, but not even close. The front brake sets the bar. Now I measured it meticulously and with a 27 mm there is about 1 mm clearance to the brake caliper.
Fortunately Challenge makes a Paris Roubaix 27 mm tubular. But 1 mm feels very tight, I would like to have about 2 mm minimum. What if the tires streach over time etc.
What are your experiences with tight clearances?