Converting from Bike Single Speed to Three (3) Speed - Intro
I have a cheap folding bike (Giant Conway) a purchased 2 years ago which is single speed, as I live in a hilly area, I spend most of the time either coasting or pushing the thing up hills. I may as well use a scooter. There is no gear hanger, and the rear drop out spacing is narrow, so I opted to replace the exist hub with a sturmey archer 3 speed. A failed attempt at gearing using a mountain bike hub can be viewed here.
Converting from Bike Single Speed to Three (3) Speed - Wheel Build
This is the first 16" (305) wheel I have built, and it was 2 cross, 28 spoker. The 2 cross lacing confused me for a while. I used stainless 14 gauge spokes from SJS.
Converting from Bike Single Speed to Three (3) Speed - Ratios / Range
The original bike had a 14 tooth sprocket which was too high-a-gear uphill and too low down hill, so I assumed that keeping the sprocket the same size on migrating would give good gearing. But no.
Sheldon brown recommends adjusting gearing so as to use the top gear as you normal gear, keeping the two the gears for inclines / climbing. And this worked out right. I didn't have any sprockets, but a free alternative was to swap chainsets. The original was 46 tooth, and I dropped to 38! Which is about right.I was surprised how much smaller I had to go.
Converting from Bike Single Speed to Three (3) Speed - Conclusion
Swapping to 3 speed?
Use Sheldon's Gear Calculator my original set-up gave 3.5 meters of development.
After Installing the 3 speed hub this changed to:
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