Originally Posted by MRT2

It depends. 52 - 40 is pretty much a classic double. In the old days, they had freewheels rather than cassettes and the smallest cog on most freewheels was a 13 or 14 tooth. These days, many freehubs have a low gear or 11 teeth so you don't need a 52 or 53 tooth chainring.

Do you ride exclusively on flats? Are you young and very fit? Or are you past 40, or 50? And do you have to climb hills? I wouldn't touch a classic double with a ten foot pole.