During WWII the supply of natural rubber was limited and was almost all used by the military. Tires were strictly rationed to civilians and available only to essential civilian users. The tires that were available used the S3 type of synthetic rubber and the sidewalls had the S3 identification. These tires had stiffer sidewalls than real rubber tires which made them be damaged easily by running under inflated or from pothole or curb damage. On the other hand the mileage from these S3 tires was about double that of the former rubber tires which on a Model A was 20,000 miles or less. The S3 tires would generally be good for around 50,000 miles on a Model A and they were made in the 21 inch size that one party questioned. Each community had a ration board for gasoline, tires and certain other items during the war. I recall having to give the ration board the serial numbers on my very well worn tires on my 1930 Coupe even though I did not apply for new ones as I was not essential and I knew I would be entering the military shortly, which did occur. When I bought my 1929 Phaeton in 1954 from the original owner, a farmer, it had a set of Goodyear S3 tires that he had obtained thru the ration board as his occupation was deemed essential. He drove only about 1200 miles per year so the tires probably had about 12,000 miles on them. I put about 45,000 more miles on them and replaced them with Canadian Goodyears as they wore out. One still rides as my spare and it looks fine with no cracking anywhere. I still own the 1930 Coupe and the 1929 Phaeton.