
I am a fan of pearl izumi wear and have been a medium in the shorts/bibs wear for decades but these bibs in a medium raised my voice by an octave or two (too small). Fortunately Biketiresdirect.com made an exchange no problem. the large are a little too large to be ideal but they are good. I am not sure if i can tell the difference between the Pro Air and the regular bibs in terms of temperature-related comfort.