Different Tire Sizes
 

Didn't think this would apply in the will it fit thread as it's not for rims.

Currently I have stock all seasons 225/45/18 tires on and am looking for winter tires and possible found some, they are 245/55/18. What are going to be the differences between the two in terms of size, wider and shorter?

The winter tires will be about 20mm wider but also 2.6 inches larger in diameter... they might be too tall for the wheel wells and they are kind of wide as well. I would pass on those and get properly sized ones.