After returning from a 2400 mile 6-day trip, my 19/45 gearing seems a bit low. It would be a lot easier to go up one tooth in the front instead of going down 3 in the rear. Essentially, it would be easier if I didn't have to resize the chain. That would allow switching back and forth between a 19T and a 20T. Does anyone know if a 20T countershaft sprocket is do- able?