4.5" skid mark left by a 7 .5" wide tread 235mm section ÷ 25.4 =9.25" tire inflated to 80 psi with only 2500 pound on the axel.
Notice there are three primary stripes Center and on the edges there are two 1/4-0"wide strips. These two 1/4-0" wide strips are the portion of the tire which contains studs which gave me traction on ice
Also notice, section width does not equal tread width. Section width is the widest point of the
sidewall measured on the specified test wheel for that tire size. And this amount of variance varies with tire size make model manufacturer wheel that is mounted on ECT ECT...