What you're thinking of is PROBABLY the width in millimeters, if the markings are something like 185/60R15.5 (although everything after "185/" might be different in your case, but that's just an example. The "185" indicates the tire width in that instance.
Great website with pictures of the tire: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=33
no
No, never mix tire sizes.
185 is larger
No, it will not.
The Tire Size is 185/70/R14
Definitely no.
No, the 185 70 r14 tire cannot be substituted for a 175 65 r14 tire. The 70 series tire has a larger diameter and is not recommended that you substitute on a 65 series tire.
Yes, it will
The standard tire size for a 2008 Nissan Versa is 185/65R15. This means the tire is 185 millimeters wide, has an aspect ratio of 65%, is a radial tire, and is designed to fit on a 15" rim.
Usually it can, but we need to see the WHOLE tire number to say for sure.
i am quite certain the tire size is 185-70-14