A little reaserach I did a while back trying to scale some wheels and tires from photographs. I *think* .. I used the grease cap to scale the wheels .. making an assumption that a Model A would have a similar size. Hard to say since this was done three years ago.
In any case .. under "The Talbot Wheels and Tires" I have a couple of charts for 1927 -
http://etraxx.com/projects/vehicles/cars-and-trucks/1927-talbot/
Unfortunately the newer online catalog lacks the 'pretty cross-sections' .. and I faied to copy it. Darn. Still .. the online catalog has a TON of technical info of classic automobile and motorcycle tires - rim width, section width, overall diameter, tread width and tire height .. good info for modeling IMO.
https://www.cokertire.com/online-catalog