Hi Guys!
I'm another Torontonian that just picked up my 2011 Edge Sport a week ago. I spoke with the parts guy at the dealer before buying and he told me you could even to to 17's as the brakes are the same size as the SE, which has 17's on it. I do think the tires will be a slightly different size though as based on the 1010 tires tire guide, the standard 17" wheels from the SE are over 3% off the 22" on the Sport, so the computer is definitely set for the different tire size. I was given a quick price of $1300 for 17" steel wheels and X-ice tires. I think I may just go with the steelies as they did look fairly nice and on my black sport, it would make it look mean ;-) I may get better snows then the x-ice though.
From what I can tell, the following sizes are within a 3% tolerance of the 265/40R22's on the 2011 Edge Sport, which is what is recommended when changing tire sizes:
235/70R17
235/75R17
235/65R18
245/60R18
235/55R20
I'm sure there are more, but most of the alternative sizes I was trying, didn't show any tires, the above sizes are all have tires available...didn't check if they were winters or not.
Note: Many other people on this forum have complained of the large rims having issues with snow backing in them and balance issues. There is some science around the fact that you should go as small a rim as possible to help prevent issues. a)Smaller rim gives less room for snow to back in. b)if snow packs in, the farther it is away from the center rotation of the tire, the more it will throw off the balance due to centrifugal force.
You can look further here: Tire Size Calculator