I did my first really cold ride today. It was 15 F. I also just got a new wheel set and this was my first ride on them. I notice that when I had my bike inside and spun the rear wheel forward, I could hear the normal little clicking as the hub spun. However, once I was outside and after the ride, when I was coasting or spun the wheel forward, it was totally silent. After the bike warmed up, the clicking was back. Should I be concerned about this? Or did the bearings just get so cold they didn't make that normal sound you hear when you coast?

I only remember riding in weather colder than this once (about 12 F) and I don't remember if I checked this or not.

Thanks.