A 1955 Massey Ferguson TO-35 tractor would have typically been fitted with tires measuring 6.00-16 on the rear, and 4.50-15 on the front. Tire size may vary depending on the particular model, and if the tires have been replaced with different sizes since it was manufactured. To find the exact size tires currently fitted to the tractor, look at the sidewall of each tire for the size information.