My wife wants a bike to ride. She wants a coaster brake. I have a 2-speed kickback hub, a Univega Viva Sport the right size for her and some bike-building experience.

My plan is to lace up a 27" rim to the kickback hub & install on the Univega. Looks like I'll have to squeeze the frame a bit to get the hub to fit. I've read up on wheel building (thankyouverymuch Sheldon, what ever roads you are riding now)

What problems & pitfalls should I be wary of? Nothing is getting removed from the Viva Sport unless it screws on.

If the frame is too wide, I'd say spacers, but then you'd have a problem with the coaster brake bracket.

I see option 1 as modifying the coaster brake bracket, but it would have to be pretty strong to hold at basically two 90-deg angles, one across and one down.

I see option 2 as cold-setting the frame narrower. Maybe find a threaded rod to put across the chainstay slots, put some washers over the dropouts, and thread it down with nuts to about 1/2" narrower than you want, let it sit a bit, and loosen. Maybe it will cold-set that way. It should, in theory.