Originally Posted by RequestTheOverhead
Well, you did the right thing by switching all of them. Two different sized tires = bad for awd. Personally I don't carry a spare (and I don't have RFT's). It's a risk, but I really don't want to put a wheel in the trunk. I just pay a little extra on the insurance for good roadside/towing service if this happens to me.
Different sized wheels doesn't necessarily mean different rolling diameters. I use a 17 inch spare along with my 18 inch wheels. Had to use it twice. Rolling diameters are the same so no prob for the AWD!