...because people need to be slapped down for answering what you yourself call a "stupid question".
gears operate on ratios. that's 4th grade math, even in kentucky. some promotion advice - if you read sheldon brown's website and browse past threads here, you will never need to ask a question again. then, and only then, will you enter the ranks of the elite, where you are bequeathed the power to post rants and talk smack.