jj,
It was 18°F in the carport this morning and my new AGM battery just didn't have the guts to spin my crankshaft through the molasses in the bottom of my engine. I tried for 3-4 minutes to start it but gave up and took the cage, wearing my leathers. Everyone at asked me if I rode my bike and I told 'em I tried. The HD crowd always says stuff like, "Boy, you're tougher than I am!". To which I reply, "I know".
I guess even in North Alabama, the 20W50 Amsoil is a wee bit thick for winter. It's up to 40°F now - let's go ride!