I had a 2011 convertible with 16 in wheels (195/55-16) and I had an extra set of winter rims/tires same size and we just got a 2012 hardtop with the 15in (175-65-15 wheels) and a donut spare.
If I put the 16 inchers on the 2012, is the donut spare (presumably designed for the 15in) ok to use on the car with 16 in wheels at the other 3 corners or should I put my can of Slime in the 2012? The tires are only 0.4in difference diameter between the 175/65-15 and 195/55-16 but those donuts always seem smaller than the originals and I dont want to be even further off size.

 

short answer is yes

from MINIMANIA's listing for a MINI donut:

If you switched from run-flat tires to standard tires, here is the spare designed for your MINI. This Spare uses the MINI factory Spare Wheel and we source the same size tire as offered on the early Cooper Spare. This spare is compatible whether you have 15", 16", or 17" tires - they all have the same approximate overall diameter. Fits R50/52/53/55/56/57/58/59

pretty common for the donut to be a different size from the 'real' wheels. Hence the warnings about speed etc . . .

{there are a lot of notes about fitment in the part description . . . esp JCW brakes}
http://new.minimania.com/part/NMW761...ver-15in-4-lug

 

Thx Capt BJ

Didnt get much use on those winter tires on the convertible so putting them on the hardtop will save some $$.