What is 90% tire depth of 14:00-R20 AT2A tires? That is the question. I see lots of used tires and many sellers call them out at 90% or better, but what really is 90%? If I am to buy said I want to insure I am getting what I seek / my moneys worth. I started digging......... If you CLICK HERE you go to Goodyears site for the 14:00-R20 AT2A tires. At the bottom you see tread depth is called out in 32's of and inch, with a new tire at 30/32's of an inch deep tread depth. If we multiply 30 times (x) .9% it equals 27. So if the math is correct 27/32's of an inch is the minimum thread depth a tire should be if it is actually 90% or better tread depth. Elaborating, 1/32" = 0.03125" , so, 27/32" = .84375 (90%) and a NEW tire depth would be .9375" of tread depth for those who want to measure w/ a depth gauge but do not have a 32" reading tire tread depth tool, of which the MILTON No. 940 works well with these monsters because it has a very long anvil (if you will) . I would assume there is a standard spot on a tire where one would measure this, that being center of tire. I would expect an inflated tire might read a deeper tread depth than a non-inflated tire.