Welcome to TBN,PACKITUP. I pose a couple of questions, 1st, what mower do you have, is it commercil grade? You see a lot of the BIG box stores sell ZTM's which are good mowers, but. . . the differentials are a stamped sheet metal and in my opinion if you added duals you'de be replacing the diff's shortly because of the torque when turning. 2nd, is the deck wide enough to cover the added wheels? and Last but most important, How steep a slope? Heres a pic of my Skag Tigercat, i've mowed slopes to about 40 degrees with it but i mow up and down not slideways. . . John