fwiw, friends who've lived for extended periods of time in both the UK and US have repeatedly told me that there is simply no exact equivalent for the "chav" style/phenomenon/culture/whatever in the US (no value judgment intended in that, just an anthropological observation). Similarities, shades of overlap, sure, but no examples of a one-to-one correspondence, certainly not the same as inner city "black" culture, etc etc, or so I've been told ...
I dunno - broadly speaking 'chav' is the UK equivalent of 'white trash'