I have 2 different styles of rib tires.
My 100 has this style
My 149 and 86 has this style
Both styles are a 4 ply tire. I use my 149 to push snow. Tractor rarely pushes sideways when moving snow.
My 8.50 ags are a 2 ply tire. The one set of 10.50s I own are a 4 ply tire. My 149 runs 8.50s when pushing snow. I have no traction problems moving snow.