Zero offset seat post places seat exactly where 25mm offset went

rodofgod76
rodofgod76 Posts: 31
in Workshop
I have a Boardman Team Carbon road bike which had what I thought was a 25mm offset 4P seatpost. I've always put up with it, but always felt I was sat too far back even with the seat as far forward as possible.

After a couple of year lay off, I've started using it on Zwift with a smart trainer. I thought I'd finally tackle the seatpost and bought a Deda Elements Zero100 0 offset post.

I've fitted it, moved the seat right forward, and when measuring it, the seat is in exactly the same place. I've even placed the old post alongside and looking at the clamp arrangement it is in the same place.

Does this mean I can't move the seat any further forward?

Comments

  • johngti
    johngti Posts: 2,508
    I guess the question is why do you feel the seat was too far back? If it's because of the reach to the bars, playing with the seat position is the wrong way to fix it - a shorter stem would be better. If it's because you can't get your knee over the pedal spindle (a good starting point even though it's really crude and needs tweaking afterwards) then the frame is probably the wrong size to start with.
  • rodofgod76
    rodofgod76 Posts: 31
    johngti said:

    I guess the question is why do you feel the seat was too far back? If it's because of the reach to the bars, playing with the seat position is the wrong way to fix it - a shorter stem would be better. If it's because you can't get your knee over the pedal spindle (a good starting point even though it's really crude and needs tweaking afterwards) then the frame is probably the wrong size to start with.

    I shortened the stem, and it helped somewhat. Knee is nearly over the spindle, but when on it lately I feel sitting in the proper position on the seat still didn't feel right.
  • joeyhalloran
    joeyhalloran Posts: 1,073
    Some seat posts have wider clamps but if you're sure you've purchased a 0 setback then it sounds like your old one wasn't a 25 setback after all.

    As above, if getting further forward is genuinely needed for your fit it would mean the bike is too big. How much seat post do you have showing? If it's not much that would also indicate the frame is on the large side for you. Do you have particularly short legs for your height?
  • First.Aspect
    First.Aspect Posts: 14,626
    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.
  • Ben6899
    Ben6899 Posts: 9,686
    First.Aspect said:

    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.


    It's a complete red herring.
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
    Instagram: https://www.instagram.com/ben_h_ppcc/
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  • davebradswmb
    davebradswmb Posts: 461
    First.Aspect said:

    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.

    They go fast because of aerodynamics. They can't generate the same power.

  • pblakeney
    pblakeney Posts: 25,750
    davebradswmb said:

    First.Aspect said:

    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.

    They go fast because of aerodynamics. They can't generate the same power.

    Link? They can push against the back of the seat so I have my doubts. Look at anyone doing leg presses.
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • johngti
    johngti Posts: 2,508
    Ben6899 said:

    First.Aspect said:

    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.


    It's a complete red herring.
    It’s a starting point not the holy grail.
  • Ben6899
    Ben6899 Posts: 9,686
    johngti said:

    Ben6899 said:

    First.Aspect said:

    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.


    It's a complete red herring.
    It’s a starting point not the holy grail.

    I think as long as you know that, and not distracted by - or fixated on - it, then all good. It's much more important - for example - to enable hip function specific to the rider.
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
    Instagram: https://www.instagram.com/ben_h_ppcc/
    Flickr: https://www.flickr.com/photos/143173475@N05/
  • joeyhalloran
    joeyhalloran Posts: 1,073
    The KOPS argument came from working out if you were on the right size bike, noit as a fitting tool. It indicates you are in the right ballpark. For a new rider or someone doing a self-fit it's a sensible place to start.

    For example upper body mass may impact saddle setback due to its impact on weight distribution.
  • masjer
    masjer Posts: 2,558
    edited March 2022
    Have you installed the saddle at the correct height? If it's higher than before, the distance from the handlebars will be greater.
    Check the handlebars are angled correctly, and the shifters aren't too low on the bars.
    You could flip the stem (raising the bars), making the reach less too.
  • First.Aspect
    First.Aspect Posts: 14,626
    pblakeney said:

    davebradswmb said:

    First.Aspect said:

    I never understand the "knee over the spindle" argument. The pedal stroke is circular, and recumbents seem to be quite fast.

    If anything, the choice of changing seat position or hand position is a handling issue.

    They go fast because of aerodynamics. They can't generate the same power.

    Link? They can push against the back of the seat so I have my doubts. Look at anyone doing leg presses.
    I've read the peak power is lower, because peak power on a normal pike is out of the saddle. I can't see how under normal pedalling it would be different though. You can recruit back, glutes and hamstrings more on a normal bike I'd guess (albeit I've only ridden a stationary bike in the recumbent position) but pretty well established that those aren't strong enough to make any different and that the pros, as you might expect, almoat exclusively push down on the pedals, and don't waste energy feebly pulling up.

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