The stock tire size for your particular Explorer is written on the drivers door jamb label.
And JDraper,1995ExplorerXLT- All the 92's in my signature(including mine) came with 225/70/15's stock. My tires were already changed to 235's when we got it, but the other two still have the 225's. All three have 3.73 gears too, but maybe that is optioned on them due to Police needs.....