You sure those weren't 245/45-16? 245/40-17 is a very common size, but I don't think anyone makes a 245/40-16.
Pretty much any 245 section tire is going to spec an 8" wide "measuring rim" and 7.5" minimum wheel. 245/45-16 is what I run on both my track cars on 8" wheels. The E1 wheels are 6.5" wide, this is said to be a cantilevered mounting, because the sidewalls are severely pulled in and the tread will not be well supported. Frankly, you'd get better transient and steady-state cornering performance from a narrower tire, say 225 or even 215 on a 6.5" wide wheel. If you just want fat tires, so be it, but watch out for clearance to the rear strut tube and wheel well sheet metal.