I rode few times this year when it was really cold(17F with windchill of 3F) and I was still wet afterwards. Problem is if I don't wear a mid layer, it's too cold because my outer shell is just a shell without any insulation.
So, if you were just wearing a base layer and a shell, you'd be cold. But would you also be sweaty? Point being, do you actually sweat when you're cold, or are you sweating in temperatures that are generally considered cold, because you're overdressed? Somewhere in between sweaty and cold is the goal. Maybe a lighter base layer or lighter mid layer (or both) is what you need.
I run fairly hot and sweaty, too, and I have to be more flexible with my layers than it sounds like you are. In temperatures like you're talking about, I often wear a short sleeved synthetic t-shirt or tank top as a base layer, and/or a long-sleeved synthetic shirt or a light 100-weight fleece shirt as a mid layer (as opposed to a 200 or 300-weight jacket). That kind of stuff is pretty cheap for the most part, so maybe try experimenting with different layers to find a happy medium.
Last edited by tigre; 02-13-2013 at 01:15 AM.