The stock wheels are anything but flimsy.
Originally Posted by nhat
if you don't wanna buy new wheels, 245/45/17 is the tallest i would go on the stock 17x8s.
This is the size I would take in the situation you are describing.
Tire height will protect the wheel from fixed vertical hits like in a pot hole or head on curb.
Don't dismiss width as it will add protection to the wheel edges from large but loose obstacles such as rocks. Width has protected my wheels more often than height.
I have driven this size on rocky roads with extreme summer tires, it will protect your wheels both with tire height and tire width, deflecting larger rocks from the wheel sides with its width as well as offering more height.
Get this size in a mud and snow and it will meet your needs better than any other size.