Based on the sizing you gave me above, I would get a size large. I am roughly your size....6ft, 170 lbs....and I wear a size Large BD2 and BC3. This gives you proper fit, plus lets you "play" with the sizing when it comes to other uses such as winter sports where added layers is a must. PM if you have problems finding a pack at your local retailer. I might have it in the warehouse. FYI: the BC3 just landed in the USA about 5 days ago. Should see it at online retailers first...such as Comp. Cyclist.sammypants said:Got some christmas cash and looking to score an ergon pack. It's between the BD2 and BC3. I am 5'10" and 170lbs. What size am I? Large or small? Thanks.