Originally Posted by Fox5

Nikat, I use 265/70/17 (which is also the factory size for new Dodge Ram 1500 pickups in case you want take-offs to size up).

They fit with no rubbing unless your control arm bushings are worn out or inner fenders are bent in a bit from whatever. The X5 suspension doesn't flex much but I've found this to be the absolute largest size possible without rubbing.

Because of the taller sidewall and stiff suspension, there will be significant body roll under high speed cornering, but 70mph freeway merging ramps are still manageable without stress. I've tested them throughout and beyond the X5's capabilities and I will say adamantly, there is no need to try cornering about 85mph with this size tire on the X5. It just isn't safe. The stock 19s for the Sport Package will allow the X5 to do triple digit corners and even pull track-like Gs and grip, but not when you have this much sidewall on 17s.

It's always good for a laugh when the tire shops have to ask me 5 times over if I'm sure this is the right size tire I want. After it's all said and done the techs always want to take pictures and are amazed it doesn't rub.