Tires: Tire numbers on side wall, tire size calculator, truck tire sizes

Question
Would you tell me the overall difference (height or width) of 225/70/r19.5 and 245/70R19.5 "F" Class tires. They will be use on a 1988 P-30 Chev. chassis, with a Maximum weight of 15,000 lbs.

Answer
Jim,

For future reference, here's a tire size calculator:

http://www.1010tires.com/TireSizeCalculator.asp

A 225/70R19.5 has a section width of 8.85" on a 6.75" rim width with an overall diameter of 31.9", while a 245/70R19.5 has a section width of 9.64" on a 7.50" rim with an overall diameter of 33.0".

Unfortunately, this web site doesn't recognize the tire sizes because they are truck tire sizes, but I inserted the rim size by looking them up in a book.  

Also a 225/70R19.5 has allowable rim width of 6" to 6.75", while a 245/70R19.5 has allowable rim width of 6.75" to 7.50".  So if the rim width is 6" you can not mount the larger tire on it.