I have a 2009 Mini Cooper can I put 205/55/15 tires on the rear of my car/. Thank you for your time in advance

Alice

 

For your MINI are you using OEM 15x5.5" rims or another width?

For OEM wheels you want to have front and rear tires to be the same size. Yes, 205/55-15 can be used on the MINI however the choice of tires is very limited in this size. It will fit OEM wheels and be correct for tire diameter.
https://www.tirerack.com/tires/TireS...earDiameter=15

You can also use 195/60-15 on OEM rims for your MINI- this allows for more choices especially for Grand Touring All Season tires
https://www.tirerack.com/tires/TireS...earDiameter=15
In general Grand Touring All Season tires give a comfortable smoother ride (with less noise) for daily street use (even on bad roads) with good grip in dry or wet and does OK with cold weather. Treadwear is more than with summer tires.