Originally Posted by jimshapiro
The gear-inch chart is OK to compare gear ratios on a single bicycle
Which is exactly what the original poster wanted.
Originally Posted by jimshapiro
And I can't for the life of me figure out why the plot is semi-logarithmic. It only covers a factor of about 4 along the x-axis and the forward movement of the bicycle in relation to the rotations of the crank, i.e., the gear-inches, couldn't be more linear. Am I missing something here?
It's semi-log in order to normalise the viewing so that one can determine appropriate overlap and shift points. the original poster is not interested in the actual numbers nor how they compare to other gear setups on other bicycles. The original poster was interested in figuring out the pattern of gearing progression on the Giant OCR2 and how it relates to which gear combination.