Originally Posted by bbattle
They run small, like most European clothes makers. So if you take a medium in PI, you'll need a large to extra large in Assos.
Assos is just too expensive for me to buy without looking at it and feeling the fabric. But others here have it and they can give you a better answer.
Personally, I wear size medium jerseys in both Assos and Pearl Izumi. Pearl Izumi's form fit jerseys have a similar chest size to Assos, but Assos is trimmer in the waist and arms. Assos is more contoured and designed to be worn skin-tight. If you are overweight, then Assos will likely not work well for you.
For shorts, I wear 1 size large Assos and size medium PI. According to the size charts, Assos shorts are designed for waists a couple of inches smaller than PI. If you're buying bibs, you also need to check their height recommendations or the bib straps may be too snug. Personally, I never buy bibs by mail order from an unknown brand, since you need to fit both the waist and height.