Letter Re: 8 Ply SUV and Light Truck Tires?

Jim:

Reading up on the article/manual “Aids to Survival“, (Western Australia Police Academy, 1998, 86 Page Word Doc once unzipped.) from the site referenced on your blog. Regarding tires .. or tyres….. they recommended 8 ply. Gosharooty, my HMMWV tires are only 6 ply. (No, they aren’t on a HMMWV, military Hummers leak, are cold in the winter and hot in the summer and they make my butt hurt.)
Anyway, how about some info on the 8 ply tire?. That just doesn’t ring a bell with me as being common in CONUS. What’s the story here? My requirement are: 32×11.50-15, and the HMMWV tires are 36×12.50×16.5
Best Regards, – The Army Aviator