Tires: Antique Truck Tire Size Conversion To Modern Tire Size, tire size conversion, balloon tires

Question
The front tires on my 1930 Model AA Ford truck are 30x5 and the rear are 32x5

Is there a chart to see what the current tire size interchange is, or what is the mathematical calculation from the old early tire sizes to modern tire sizes.

Question 2 is: what is the difference between "Balloon Tires" and "High Pressure Tires" from the 1930's

Answer
Eric,

First, these old tires generally do NOT have modern equivalents.  The way tires are designed has changed tremendously in the 80 years between now and then.

Even though it will not be much help to you, I have developed a conversion page for more recent tire sizing systems:

http://www.barrystiretech.com/vintagetireexchange.html

I also cover different tire sizing systems here:

http://www.barrystiretech.com/tiresizing.html

Unfortunately, those pages are for post WWII tires and the sizes you mentioned are earlier.

High Pressure Tires?  Those are what you are looking at.  They were called that because the next generation of tires were larger and used lower inflation pressures and they called them "Balloon" tires.

I'm afraid you are going to have to do some digging.  I suggest you contact people who have vehicles similar to yours.  There should be web sites around.  I found a few, but they didn't have what I was looking for.  

I think the operative words here are patience and perseverance.

Good Luck