I am thinking about using an underpad...

In my travels this past week, I struck up a conversation with a head mechanic at one of the bike shops I visited.  This gentleman does very long rides, even in the winter.  It is not uncommon to ride 4 hours in below freezing weather.  He shared a few secrets on how he stayed warm.  Most of the things I had heard of, but one thing he mentioned, I thought, was ingenious and I had never heard before.

He buys underpads from Walgreens, cuts them in half and then puts this pad against his chest, underneath his base layer.  The layer provides 2 functions:  It first wicks sweat to keep the rider dry, especially when the rider is going with the wind.  Next, it provides addional insulation and wind protection.  For him, after 2 hours, the pad is wet and he needs to change it.  So if you are going for a long ride, make sure you bring the other half with you in a ziploc bag.

I look forward to trying this trick.