So I got Bev a second Swytch kit partly because the old one was pre-covid and would need replacement possibly given the age of the battery. A new battery wouldn't have the discount so I could buy another kit for about the same cost. But rather than purchase the same wheel size, I ordered the 700c kit. Then for a birthday present, I got her a 29er mountain bike. So I put that new wheel into service and determined to re-build the old hub as a 700c. My first order for spokes I roughly measured the spokes on the new wheel and came up with a 260mm length. I failed to appreciate the nuance of wheel building and discovered they wouldn't work because they were between the two sizes I would need to single cross and two cross wheels. In fact, there are radial, single, double, triple and four cross builds. Who knew! So after that failure, I used an online utility to determine the effective rim diameter, ERD. and used a spoke length calculator to determine what spokes it needed. The requi...