So I have a nice pair of windbreaker pants from REI, the Headwind pants:
These are just fine down into the low 40s. 30s and 20s they are not so comfortable though. I'd like to get a lightweight bottom baselayer or perhaps a long underwear or tights that I could wear underneath the Headwind pants.
I bought a pair of cheap base layer bottoms from Target that were awful because they were not very flexible. Relatively speaking biking requires a large range of motion with your legs, compared with say jogging or walking or swimming so I really need something flexible.
On the other end of the price spectrum, I have awesome merino wool tops but I think merino wool would be too warm as bottoms given that my legs are pumping when riding.
A lot of long underwear is cotton and mid or expedition weight so it would either soak up sweat or be too bulky and is not appropriate when layering under other cycling clothes. I think I need something that is lightweight since I'm keeping relatively warm from pedaling and already have the wind breaker layer on top.
So is there any bottom (links greatly appreciated) out there in your experience that is lightweight and flexible to wear under a windbreaker type pant?