My son's 760T has a 195/60 R15 on the steel rim for the spare tire. It fits fine in the spare tire cavity. The reason car manufactures went to the donut spare was for weight saving (every pound saved gives a tiny boost to fuel economy figures) and cost. I don't like the donut spares because they will roll over on the rim and put you in trouble when you drive on them. We were in on vacation two year ago and about 600 miles from home when one of the 17 inch tires on the wife's 745T let go. We came home on the donut spare. I can tell you that when you corner and the donut spare is on the outside rear tire of the turn, you can have some exciting experiences when the car tries to spin out.