I've never replaced a coaster brake hub, but it doesn't seem that complex. It's a series of bearings and sprockets wrapped around an axel. The reason I don't want to use a caliper brake is because the bike wasn't designed for one.

I commute to work on an old single speed bike that I don't want to worry about getting ripped off and spending a lot of money for. I could probably get the thing rebuilt at a bike shop for around $40, but I can get a rebuild kit or even just the bearings for a lot less. The entire bike only cost around $80 and I could still replace the thing for around that much buying on the Internet shipping included.

I might consider putting a caliper on, but only for safety reasons. I'm a bit paranoid about the thing failing and having no way to stop. I still prefer coaster bakes because of the ease of use.

Does anybody know about different hub rebuild kits? I think I'm inclined just to buy a second bike just to keep around for spare parts.