The 8.75R 16.5" Cooper tire that I have coming is 29.42" dia., with a 6.75" tread width. Here is my mistake, 16.5" rim gives you ...Oops %^$#&* , I forgot to divide by two. I get 12.92"/2=6.46"(side wall ht)and the over all width is 8.4". So 6.4"/8.6"=.751 or I guess it's really a series 75 after all, my mistake.
My bias plies were 29.5" with a tread width of 6" and over all width of around 8", I guess they are somewhere around 85 series.
Denny Graham
Sandwich, IL
