I bought studded snow tires when I started commuting to get to work safely in the snow. They are great in the weather, but I've also gone entire winter seasons without needing them. This season I bought non-studded winter tires with the idea of keeping them on the bike all winter. For my climate, they were probably a smarter purchase than the super heavy duty studded tires.

I am looking for suggestions regarding when, temperature wise, to change over to my winter tires. Riding temperatures this time of year are in the 30's, 40's, and 50's. In the past I have ridden regular summer tires down to about 15 degrees F, and they seemed just fine.

The danger with non-winter tires is that the rubber hardens in the cold, making them extra slippery on ice patches and hardened snow. I usually plan to switch to the non-studded Continental Winter tires in late fall, but it happens when ice patches appear in practice.

Not sure what you are asking? Changing over from summer tires to non-studded winter tires? In the mild temps of a Jersey winter, I don't think temperature is the main consideration, but rather road conditions, dry clean road vs. otherwise.

More important, also, is lowering tire pressure when there is ice/snow/slush. Better for keeping the rubber side down.