Originally Posted by
noglider
Your lowest gear will be 28/21*27 which works out to 36 gear inches. That is low enough for climbing a hill with luggage on the bike, for most people. Some people would prefer a lower low and would replace the freewheel. I never feel the need for a gear lower than 36 inches, but I'm better at hill climbing than some people.
Thanks noglider. If I understand the formula you used, you take the number of teeth on the smallest crank, and divide that by the number of teeth on the largest ring on the freewheel, and multiply that by the size of the wheel to get gear inches. Is that correct?