A friend of mine also measured his and got just under 10 1/4". M/T's website states 10.0 for the 28 x 10.50's and 10.9 for the "W". Mine measure 10.9-11.0 and I have measured them several times. I would not really be concerned but I want to switch to drag radials and I want to get as wide as I can get & have them fit. The 325/50/15 radials state they have a 13.1" section width and that is what my tires measure, but if the measurements are not accurate then the radials could actually be 14-14 1/2" which will be too much. Maybe I should ask if anyone has a 325/50/15 M/T radial on a 10" rim if they could measure the section width. Thanks for all the responses.
John