As most of you might know, I have modified a Dahon single speed Boardwalk with a 3-speed Shimano Nexus internal hub. The bike is actually my wife's and she is a small girl and not a strong or fast rider. Our city bike paths are mostly flat except when they go under freeways and roads. Thats when you have a nice ride down and a hell of a ride up! There are about 5 or 6 of these under paths and 3 or 4 moderately steep bridges, so as you can see that actually a decent amount of uphill riding.
Now I am wanting to switch out the rear cog on this bike to make things a bit easier for my wife but can't decide on what size rear cog.
This is how the ratio is set up right now with a 44t chainring and 14t rear cog:
1st (-36.4): 46.1 inches
2nd (1:1): 62.9
3rd (+36%): 85.5
With a 16t rear cog:
With 17t rear cog:
And finally with an 18t rear cog:
Though 17 or 18t rear cog might sound nutty, please remember that we are just leisurely type riders and we never need to go that fast or more than 8 or 10 miles at furthest. So having the 3rd gear as the main gear isn't a big problem. I would just like to have your opinion and advice please.