96 XJ tire size issue

Ok so my 96 XJ currently has 16 inch rims that came from another jeep,i have 235/70/16 tires on them and i am thinking about going back to the stock 15 inch rims. the Rims i am looking at are pictured below.So my question is what tire size should i use? i think the stock size is 225/75/15. i like the look of my current size tires but was wondering how much of a difference it would look like with the stock size versus what i have on now I do have 2inch lift

http://static.summitracing.com/global/images/prod/large/mtt-158421_w.jpg

There's a really good tire size comparing tool here:

http://www.1010tires.com/tiresizecalculator.asp


Using your numbers, looks like your current tires will indicate slow on the speedo. When you switch back you'll start getting better mileage and have better performance.