Interesting comment by the LBS tech during a recent visit. He mentioned that they don't see setback seat posts much these days because it changes the pedal stroke. Tech also said that the saddle should ideally be in the "middle", meaning the clamp should be more center on the saddle rail. i wouldn't be able to tell the difference in pedal strokes. My setback Thomson feels good but the saddle is pushed to nearly the back end of the rails.

Does it really matter?

All other things being equal, you can generate more power sitting forward. The problem with this is trying to maintain this position and power output per stroke for hours on end. We need to sit back a bit to get the weight of our upper bodies off our hands, and pounding the pedals all day is hard on the knees and quads. Sitting back allows the back muscles to do more work supporting the upper body and brings the hamstrings into the pedal stroke.

I have long femurs, too, but frankly I have no idea where my kneecap is relative to the pedal spindle at 3 o'clock. I do know I can ride for hours without any kind of discomfort above the waist, and I can easily sit on the nose or get out of the saddle without throwing my balance off.

Silliness. Of course one can tell the difference. The big difference is that, as above, a more set-back saddle takes weight off your hands, which is good thing. A more set-back saddle increases usage of hams and glutes, especially when climbing, also a good thing. Sitting more forward opens the hip angle in an aero position, which will make it easier to breathe when going hard. That's why one sees riders "on the rivet" when going fast on the flat. There's no rule, it's just about what one wants to emphasize.

Saddle position also affects reach, so every cm you move the saddle, you have to move the bars the same amount to maintain the same reach.

Saying that there's a proper position for the saddle and that's the same for everyone and everyone's goals is silliness.

Proper fit is a proper fit. If it takes a setback to get there then whats the difference? Nonsense from you LBS.......

LBS owner: 'I accidentally ordered 20 of these 0-setback seat posts instead of two."

LBS employee: "I can probably help get rid of them."

It's all about fit. I've got to be in front of KOPS. Some people's individual anatomy puts them behind it.
The position of the saddle rail in the clamp has nothing to do with the rail and everything to do with the rider.
Sure, they were engineered to fit the widest range of individuals.

Maybe the most common position is right in the middle. That's where I had my first bike for 2 years -- because it was set by an LBS that told me things like yours did -- and that's why I go to another LBS now.

Rule # 20

LBS tech is a moron

I find setback posts to have a bit more compliance than a 0mm. In addition, fore/aft position in relation to the distance from the bottom bracket is most important to me. Maximizing your power output while not causing a strain to your lower back is a game of millimeters.

I use zero setback posts because it gets me in the position I want to be on the bike. You don't want to slam the saddle forwards or backwards in the seatpost cradle such that you're clamping outside the recommended area on the saddle rails.

The UCI rules state that a saddle has to be a minimum of 5cm behind the centerline of the bottom bracket. So for a lot of people a zero degree post would have the saddle way forward on the rails, especially with an aggressive ST angle. So I guess that's why most bikes come with setback posts, who knows.

Get a proper fit, if they are selling lots of 0 setback posts, it must a local thing.

Haha, if that works for him, it's a fabulous thing, but that has little to nothing to do with you. Also, Greg LeMond, last time I checked, would disagree with this fellow, advocating getting behind the pedals, and seat back as far as it'll go. Having said that, it is still all about what works in your skin. Ride on.

Let me guess, he is 20 years old, has only been riding for a couple years, and doesn't know how to really work on bikes except for assembling the latest and the greatest.