My car also underwent a tire and wheel change - 195/50-15's and 15x6 Rials on all four corners.
Reason - permitted unencumbered rotation, better handling (less understeer, more sure-footed, quicker turn-in), smoother and more stable ride, more readily available tire size and cheaper price, wheels look better and are easier to clean.
The 195/50-15's were chosen because they were almost an exact diameter replacement, because they are a common size and easily available, because they look good on this car, because they have a softer sidewall and less harsh ride, because the price was right.
An original front tire mounted on the OEM wheel does fit nicely behind the passenger seat still leaving good leg room for the passenger. The tire is covered with a vinyl tire cover. The jack fits behind the driver's seat.
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