Did some searching didnt really find anything. I thought 4 rear sedan wheels for my AWD sedan. 18x8.5. Should I run 225 all around or 245? Would there be any fitment issues?

 

245 no more than 265

 

Would 245/40 be the best size to run on 4 18x8.5's?
Or 245/45?

 

245/45/18 would be close to the stock rolling diameter of the 225/55/17.

 

Use a tire calculator to determine the diameter of your OE tires. You can deviate no more than 3% from that value before the ECU starts complaining and lighting up the dash. Compare the 245/45 and 245/40 with the OE diameter and you can tell which one to buy.