I'm fitting a clincher tire that's usually 2-4mm wider than the original tire. It's usually the largest tire that will fit with reasonable chainstay clearance.
I had a Miyata 615 and used 700x32 with good results. I'd recommend a 28 or 32.
1971 Peugeot PX10: 28x23 originally, 700x32 Compass Stampede Pass currently, measure 31.5mm wide
1972 Schwinn Paramount: 28x23 originally, 700x28 Vittoria Corsa currently, measure 28mm wide
1977 Motobecane Grand Record: 27x1 1/8 originally, 700x28 Panaracer Gravelking currently, 28mm wide
1984 De Rosa Professional: 28x23 originally, 700x25 Vittoria Corsa currently, measure 27mm wide
1985 Serotta Nova Special X: 700x23 originally, 700x27 Vittoria Pave currently, measure 27mm wide
1986 Eddy Merckx Corsa Extra: 28x23 originally, 700x25 Vittoria Pave currently, measure 26mm wide
1995ish Pinarello Gavia: 700x23 originally, 700x25 Vittoria Rubino Pro currently, measure 25.5mm wide
1995ish Simoncini Cyclocross Special: 700x28 originally, 700x27 Challenge Parigi-Roubaix currently, these measure 30mm wide
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Last edited by Barrettscv; 09-30-17 at 08:39 PM.