The W slick is 13.6 section width on a 29.5 tread width is 11.2

29.5 non W stiffwall is section width 13.2 and 10.2 tread width
a regular 29.5 is 13.1 section width and 10.2 tread width.

Hope this helps. This is with Mickey Thompson

But a 31 x 10.5W, the section width jumps up to 14.5 and tread width goes to 10.8