Originally Posted by
pdxtex
so why would i want to be further from the handlebars?? setback posts make no sense to me. a straight post on a non compact frame with a shorter stem seems like the way to go. meh......
It's impossible to generalize this. it's all about getting the rider in the best position in relation to the pedals. Whether that requires a setback post, depends on the frame angles, the particular rider's anatomy, and the amount of adjustment you have available in the seat rails.
FWIW, On my road bike, I've got a set back seat post with the saddle pushed pretty far forward on the rails. On the tandem, I've got a no setback seat post, with the saddle about as far back as it can go on the rails. I've got the same position in relation to the pedals on both bikes.