Largest tire on factory 17" rims?

[Puch]

Hi all, I'm a new member with my first post, and of course its a question - what is the biggest size tire I can go with on my factory 17 x 7.5 rims? My X5 is a 2006 3.0i, and I would like to go with a wider all-season tire than the current 235/65/17 Michelins.

Also, what effect can larger tires have on my X5, both long and short term?

Thanks in advance for your help.

[jst2878]

you could buy new rims and go much wider. on those wheels you couldn't do any more than 245

[x54.4blue]

It would that larger (wide) tires cause more drag, which reduces mpg?