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  1. #1
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    Zero Setback Seatpost?

    What are the advantages of a zero setback seatpost? Can these be used in place of a shorter stem?

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  2. #2
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    Well, without being an expert, I would say no. You should place your saddle first than use a proper stem length. That's what I do, I just can't ride with a setback seatpost...

  3. #3
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    Zero setback seatposts, like any seatpost, are to position you in the correct place relative to a vertical line projected up from the bottom bracket. They do this in conjunction with the seat tube angle. Top tube length, along with stem length, accounts for reach.
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  4. #4
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    Quote Originally Posted by bylerj1 View Post
    What are the advantages of a zero setback seatpost? Can these be used in place of a shorter stem?
    Yes and no. In theory you should position your saddle fore-aft first, and then your bars/stem. The problem with this theory is that there is no science based or evidence based method of fore-aft saddle positioning. The only real guideline out there (supported by basic geometry) is that the more forward you are, the less acute your hip angle will be when you bend down to reach the bars. So, if you have a lot of saddle-to-bar drop, it's not a bad idea to get more forward and use a zero-offset seatpost. But there may be advantages to being slightly forward even if you don't ride with a lot of drop.

  5. #5
    Cumudgitude
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    Quote Originally Posted by darkspeedworks View Post
    The problem with this theory is that there is no science based or evidence based method of fore-aft saddle positioning.
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  6. #6
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    Quote Originally Posted by darkspeedworks View Post
    Yes and no. In theory you should position your saddle fore-aft first, and then your bars/stem. The problem with this theory is that there is no science based or evidence based method of fore-aft saddle positioning. The only real guideline out there (supported by basic geometry) is that the more forward you are, the less acute your hip angle will be when you bend down to reach the bars. So, if you have a lot of saddle-to-bar drop, it's not a bad idea to get more forward and use a zero-offset seatpost. But there may be advantages to being slightly forward even if you don't ride with a lot of drop.
    A further forward postion puts more weight on your hands. A common mistake is to place the saddle too far forward, based on a knee over pedal measurement, then later raise the bars because the rider has too much weight on their hands. Two wrongs don't make a right. A saddle placed further back will produce a postion where the rider is balanced over the saddle, there is little weight on the hands and the saddle to bar drop can be quite large, without discomfort. That's a typical pro rider postion.

  7. #7
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    Zero setbacks were the standard before compact frames came about. The setback seatpost moves you a little further away from the cockpit, but it's real purpose is to move your knee further back in relation to the bottom bracket.

    I have a bike with a long top-tube and a small rear triangle. I ride with a zero-setback and 90mm stem on that bike, but really, I'd probably be better off with a bike with a shorter top tube.

  8. #8
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    Quote Originally Posted by C-40 View Post
    A further forward position puts more weight on your hands. A common mistake is to place the saddle too far forward, based on a knee over pedal measurement, then later raise the bars because the rider has too much weight on their hands.
    In my experience, a lot of saddle-to-bar drop puts more weight on your hands. Less drop puts less weight on your hands. Saddle fore-aft postion in the tiny range most people are talking about here seems to affect this very little.

    Based on your criteria, if a more forward saddle postion puts more weight on your hands, then how far forward is "too forward", and how much weight is "too much weight" on your hands? And how could this be determined in a fit studio (vs. on a 5 hr ride). And when have you heard a rider say, "you know, there's just too much weight on my hands, I guess I need to slide my saddle back." ? Or a rider say the converse? Me? Never.

    Again, there is no evidence based criteria for saddle fore-aft position. When I say this I mean a criteria that is based on some sound research and that can generate an actual number for a particular rider for seat fore-aft position.

    But this is a good discussion and I've been wrong before, so I'd be happy to listen to solid evidence to the contrary. Seriously.

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  9. #9
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    I really like Peter White's discussion of saddle fore/aft placement.

    How to Fit a Bicycle

    It always amuses me a little bit when people want to see evidence-based study of this stuff. I wonder if they've ever tried to do a study, or to get someone to pay for one.

    But ultimately, this is isn't something that's too hard to figure out when there's a clear goal. I think most of us would say something along the lines of, "I want to be comfortable on my bike." And I think most of us would also have to admit some qualifiers like "on my usual kind of ride." One of the things Peter White is saying, and I agree, is that people balance differently on their bikes depending on how much power they're developing. It's not too hard to notice this on oneself.

    I'm a fan of his method because one person can do it without buying additional stuff and it addresses something that's qualitative without making an awkward visit to math-land.

    For me, sliding my saddle forward tends to result in more weight on my hands. Somewhat counterintuitive, though not too hard to "prove" to myself once I know the result I'm looking for, and also opposite what the OP's second question implies as his goal.

  10. #10
    wim
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    Quote Originally Posted by TiCoyote View Post
    Zero setbacks were the standard before compact frames came about .
    Hmm, I remember the setback seatpost being the standard back in the day. It was designed to put most riders into a balanced position on most frames and it did its job well. Not sure how and why "compact" frames would change anything in that regard. All they are are standard bicycle frames on which one end of the top tube has been moved down and the resulting excess seat tube material lopped off.

    As to "more forward and more upright": That often does put more pressure on hands, wrists and neck than a low and stretched-out position would. The unfortunate thing about this is the fact that many riders (especially beginners) try to fix that with "even more forward and even more upright."
    Last edited by wim; 03-17-2013 at 06:44 PM.

  11. #11
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    Quote Originally Posted by wim View Post
    Not sure how and why "compact" frames would change anything..........All they are are standard bicycle frames on which one end of the top tube has been moved down and the resulting excess seat tube material lopped off.
    I'm not sure how a "compact" frame would change anything either. They just have a lower seat lug or seat post collar area.
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