Do bikers wear earrings in their left ear?

That's like asking what ear do warriors or pirates wear their jewelry. We wear rings, studs etc in either or both ears and sometimes multiple rings in one ear. Which one doesn't really matter anymore. Bikers tend to wear larger ear rings than you might find the average citizen or more "in your face". The "style" of what is now termed Goth has been worn by Bikers long before they existed. The same is true for the jewelry Rockers wore until the 80's when Rocker jewelry got a bit "delicate" for Biker taste. The bottom line is that a Biker wears what he wants, when he wants and where he wants as long as it shows no disrepect to those with whom he rides. There are no rules for jewelry...if there were, we probably wouldn't do it.