Originally Posted by

**11.4**
The calculation is chainring teeth divided by cog teeth, multiplied by a constant. Whatever you want to make the constant, it still is a reliable ratio to use for comparison of gearing. It happens to work into a number that is big enough so you aren't working out into two decimal places plus it's something everyone has worked with for years. If you want to go around saying your gear ratio is 2.328, fine. Even on the track where people are changing gears repeatedly in an evening, and a couple inches worth of gear is meaningful, people just use the traditional measure. Frankly, there aren't many road wheels that aren't 700C any more and nobody's going to get pedantic about the measurement. You have to multiply the gear (in inches) by pi anyway to get rollout, which means you could argue that no one's expressed it right since time began anyway. Time to move on. Next thread?