Ah-hah!

I just went through TireRacks decision tree and they came up with your model. Of course, they are sold out for the season.

Until now, I did not realize there were differences that rest upon the adjective "performance."

It looks like this tire is not available in 235/60-18 but in 255/55-18.

 

Exactly. Performance snow tires are a compromise so they still work like an AS tire on the dry. Dedicated snow tires compromise dry performance for snow capability. I have the 255's and they have worked great for a pretty crazy winter. So far we have received 20-28 feet of snow above 6500 feet this season.

 

Wow, we've got little snow left. It is a FRIGID and ICY winter. My concern is ICE. It seems like narrower tires might dig down better.

 

While some people may disagree with me, I have found the opposite. The whole narrow snow tire thing came about due to the concept of driving in deep snow. A narrower tire is less likely to become a plow allowing it to move through the snow. However on packed snow and ice, IMHO, the goal would be to distribute as much weight across the contact patch as possible. This allows more sipes (the main element of snow tires that provide traction) to hit the snow. Adding more weight to a smaller contact patch eventually reduces the friction available - think Ice skates - the blades are thin, not wide.

 

Those are the two approaches, theories. Sometimes it is better to chop thru the slop, other times better to ride on top. Snow, ice, slush have so many qualities/states that it's hard to get it right.