LesterOfPuppets

I love U-Brakes. It's the location that make that one kinda suck a little for cleaning and adjusting, kinda suck a LOT on mud rides.

Late 80s sounds about right to me kenhill3, I reckon 89 or so.

I'd assume the rear derailer is original. They might have opted for mid-cage thinking 24" wheels, so you don't want a long cage dangling closer to the rocks on the trail???

I'd still run that derailer if it was mine, just stay out of the 28x14 (or whatever low gear is). If you want to problem-proof it for a youngin' to ride I'd swap out for a derailer that pulled more chain,though.