Originally Posted by
billridesbikes
All things being equal bigger cogs in the back are more efficient than smaller ones by a larger amount then I would have guessed so it pays to have your favorite gear in a straight line and set up the gearing so this is a largish cog. So if your favorite gear is 46-15 switching to 50-16 would be slightly more efficient by about a 1%.
This sounds questionable because given the same gear ratio on the same bike, the angles between the chain/sprocket tangent points are the same, resulting in the sum of the angles subtended by the links to be the same regardless of sprocket size (ratio held constant) - basically big sprockets mean more links at less angle and small sprockets mean less links at more angle.