So my bike has very short dropouts that allow for just about no adjustment, it is a conversion. Right now i run a 39/14 which is about a 1/3rd ratio it is a little rough for commuting and recreation all though managable but i was wondering if there was a way mathematically to determine my other gearing options using different cogs and chainrings. any help would be cool. thanks.
Online calculator: http://eehouse.org/fixin/
Originally Posted by ouch
There are also eccentric hubs (the axle bolt is not in the center of the axle) to give you a little more range. As always, Sheldon Brown has the answers, or at least the links to the answers.