Many 700c size modern tubular tyres should fit.
They are available in different widths to suit the rim widths.
They are also available for 26" and 24" diameter sizes, but with fewer options of tyre width available.
Firefite: If the outside diameter of your rim measures 25" ( or within 1/4" of that ) you will need 28" singletube tires.
It is true that there are modern 700 mm tubular tires available that will fit on your rims however they do not even come close to resembling an original with sidewalls decorated with bright colores writing and logos. Plus the thread are very modern in style. Note that you cannot use either a tube type tire or a clincher type on the rims shown in your pictures. Your best bet, as noted by other responders to your inquiry are tire made by Robert Dean. Robert's address is: Robert Dean - 600 Dillon Street - Saint Albans, WV 25177. His contact phone number (which is not a cell phone) is
304-380-5710. He produces 28" tubular tires in 3 colors: Black, White, and Red ( the red tires are bright red and would look way out of place on your bike. The smooth tires have no tread pattern and are 1-3/4" wide and, in my view, are as close to original rideable tires in their appearence as can be found today. Another type tire Robert produces has a straight linear tread pattern, is 1-5/8' wide, and, in my view does not look quite right on these old machines. If you have no intention to ride the bike an other altenative for you would the solid rubber 28" reproduction display tires produced by Univeral Tires in Pennsylvania. These solid tires have little, if any, road shock absorbsion ability which, if ridden on anything other than smooth pavement could damage the frame welds on these bikes which could be a real danger to the rider. Their appearence though makes them an excellent choice for display and museum quality restorations. The RD tires are not cheap ( I recently purchased a set for $300. ) Please remember that tubular (single tube) tires must be glue onto the rims - they are commonly referred to as
"glue-on" tires. I hope this is of some help you in finding a proper set of tires for your project. On my website: email@example.com) you'll find numerous pictures of my resoration work showing a variety of the tires I mention here......none of which have the straight linear tread RD Tires. Good luck, Dick Rath
Time Machines Limited features antique bicycles, classic bicycles, restored bicycles, vintage bicycles, wood wheel bicycles, TOC turn of the century bicycles, pneumatic safety bicycles restored and conserved by Dick Rath of Greenville, New York and Sebastian, Florida.