Where can one purchase 700x21C gumwall clincher tires these days? (And hopefully for less than car tire costs.)
With my last retro bike build, I bought a pair of Michelin Dynamic Classic tires in 700x23C size which is as close as I could get to what I really want, but even those tires are hard to find. The few tires I've found in a 700x21C size are all black (i.e., no gumwall) which I think looks odd on a retro build. I remember riding even narrower tires than a 700x21C when I was young and couldn't find anything wider, but I'm guessing I'll never find a 700x20C or 700x19C these days. Note that this bike build is going to be largely a wall hanging, so the tire width is more about remembering the past than it is about comfort, ride quality, or speed.
Semi related... 35 years ago, one could hardly find a road bike tire wider than 700x23C at one's local bike shop, now it's nearly impossible to find one narrower than a 700x25C. I wish the bike industry would've discovered wider tires decades ago which would've saved me a lot of physical pain.
I now ride 700x32C and love 'em... and I would've considered that a mountain bike tire when I was younger.