Winter tire sizing
 

My 2016 RDX is running on 235/60/R18 tires. I want to get a set of winter tires (Bridgestone Blizzak WS 90 or Michelin X-Ice Snow). I’d like to go a narrower tire on a 17 inch rim for my winters - would 215/55/R17 tires fit or do I need a deeper sidewall (higher aspect ratio)?