Putting larger tires on the machine is not really going to hurt anything unless you use rims that have additional offset. Take a look at where the flange is located on the rims you have. The more centered the better. If you are going to split your existing rims to use with larger tires, add the material to the short side to hopefully end up pretty well centered. Then, use axle extensions (like they use with duals that have the tie rod down below) to move the tires out where you want them. With that setup axle, frame, final drive and rim problems just won't be an issue.