I have four A's on the road, two with 21" (Garfield and Firestone) and two with 19" (Goodyear and Firestone). I keep all the tires at 35 pounds. Gar Williams
The owner's manual says 35, and 40 on the rear of pickups and station wagon. I keep mine at 35. It rides a bit rougher, but takes the corners more securely.