Hi folks,
How do the over all diameters compare to the following tires on my vanagon and another list members?

Mine 
225/55 R17 

Karl’s 
225/70 R16 

I’m wondering if Karl’s over all diameter is the same larger or smaller. 

If larger, what would I need to do to match his size on my R17 rims when future tires are needed.

Eric Caron