Joined: Jan 2009
Posts: 44,167
Likes: 6,387
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
I measured it just now. Sorry it took so long. It came to 20.5 mm, which I suppose is close to 13/16". My caliper isn't the best.