i think if a person weighs a chubby 285 or so 18 or even 19 inch arms arent all that spectaculer,its when that person gets down to around 10% the true measuerment of muscle will be accurate,i see chubby guys in the gym with 18 inch pipes all the time but you cant even see the main bicep vein or for that matter you cant see any veins.even arnold only had alittle over 19 inches and sergio was alittle bigger like almost but not quite 20,and i doubt your gonna find to many arms on this board that look as good as those 2 champions.i was never one to get caught up in the tape measure thing,when i was 12 or 13 years old i used to but thats about it,my mirror is my tape measure cause when its all said and done its all about who looks the biggest and best and not who really is the biggest,most of times a lighter harder bodybuilder will appear larger then a much heavier smoother bodybuilder even though the scale and tapemeasure say different