| Tooth counts for this hub were reverse-engineered. See
description for the Torpedo 7-speed to see how this is done. Only tooth
counts shown in red in the table here were entered manually for the reverse
engineering. The formula used in this process is in the cell in the top row
for the 12-tooth planet gear, in the Excel version of this page, This formula
solves for the planet gear when the hub's highest ratio is known. Because of
rounding of the decimal ratio from the product brochure, calculation for the
23-tooth planet gear did not come out exact. I revised the result, and so, in
the Excel file, you will find no formula for the 23-tooth gear. The surprise
in this worksheet is the exact ratio of 115/143 rather than 37/46. Both round
to the same decimal numbers. |