What size spare???

205-65-15 on a 6" wheel. This will give you the same height for use on the rear and will be narrow enough for the front.

Your 225-60-15 is about 25.6" tall.

The 205-65-15 is about 25.5" tall.

This is assuming that you are rubbing in the front with the 225-60-15s because of width and/or wheel offset.

The 225-60 and 205-65 are both about stock height.