Tires: toyota 2002 camry, tire failure, winter tire

Question
my tire size is a p205 65/r15     Can I purchase a winter tire size 195 65/r15???  will this fit my car??  Not sure what the first three numbers indicate in tire sizing?  could you please advise

Answer
Aimee,

This is not a good idea.  That would be going down in load carrying capacity and that increases the risk of an overloaded tire failure - which can sometimes have tragic results.

What do the numbers mean?

Tire rack explained this much better than I can:

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=46