use a UA Coldgear long-sleeve shirt as a primary base layer.

best thing I've purachased for winter riding. really like the form-fit and excellent wicking properties.

only problem is that it's almost too warm...temps need to be ~45F or lower or I overheat. above that temp, I can get by with jersey, arm warmers, and wind breaker.

with the UA top, fleece bibs, full-finger gloves, good down to low 30s.