Re: Hello - building kit bike to Triumph Bicycle
A couple of things: 1st, I'd love to have a Triumph decal like that one on your tank. That's too cool.
I tried to find Sturmey Archer parts a couple of years ago and found plenty in England. There are collectors of those old 3 speed hubs but are willing to part with them but they're proud of them so expect to pay top dollar. I agree with the idea to replace the rear wheel, save your original, and find a good coaster brake hub.
I've not had to deal with the extended crank arms so I'd listen to the advice from the guys who have on that point.
It is a good looking bike, thanks for sharing and welcome to the forum. Don't hesitate to ask all the questions you want. We're all here to help and have fun.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"