Zero offset seat posts on road bikes

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BrownBike
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Zero offset seat posts on road bikes

Postby BrownBike » Fri Mar 28, 2014 7:06 pm

Had a bike fit and was recommended that I switch my seat post to a zero offset version to get my position more forward (low flexibility with long thighbones).

I notice that a lot of these seat posts are marketed as being for MTBs. Is there any reason for this other than MTBs usually having them? So long as the diameter and length is OK, any problem with whacking one on a carbon roadie?

Thanks for any info!

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trailgumby
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Re: Zero offset seat posts on road bikes

Postby trailgumby » Fri Mar 28, 2014 8:49 pm

None at all. Am thinking of doing so myself, so my position is closer to my mtbs.

The only thing to watch is seatpost diameter. 27.2 is less common these days on mountain bikes, they tend to favour 30.9 or 31.8 which may limit your choices.

I rather like Easton EC70 myself. Light, resilient, not horribly expensive.

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eeksll
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Re: Zero offset seat posts on road bikes

Postby eeksll » Fri Mar 28, 2014 10:02 pm

3T, Easton, FSA (and presumably alot of others) make a offset and a zero offset for most of their seatpost line.

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Ross
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Re: Zero offset seat posts on road bikes

Postby Ross » Sat Mar 29, 2014 5:30 am

I have a Thomson zero offset post on my bike(s). The nase model one is called Elite but you can buy a lighter, more expensive version called Masterpiece.

Not sure why most road bikes these days come with laid back posts, markeying gimick I think.


http://www.this link is broken.au/thomson-elite- ... vAodSmQAvw" onclick="window.open(this.href);return false;

warthog1
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Re: Zero offset seat posts on road bikes

Postby warthog1 » Sat Mar 29, 2014 9:58 am

Ross wrote:I have a Thomson zero offset post on my bike(s). The nase model one is called Elite but you can buy a lighter, more expensive version called Masterpiece.

Not sure why most road bikes these days come with laid back posts, markeying gimick I think.


http://www.this link is broken.au/thomson-elite- ... vAodSmQAvw" onclick="window.open(this.href);return false;

I have one of those that has now outlived two frames, it's on it's third. Strong, light and secure. I highly recommend one too.
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BrownBike
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Re: Zero offset seat posts on road bikes

Postby BrownBike » Mon Mar 31, 2014 2:20 am

Cool, thanks all. Thomson looks good, seems to be plenty of choice though.

BriP
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Re: Zero offset seat posts on road bikes

Postby BriP » Wed Apr 02, 2014 7:07 pm

i run an fsa 0sb carbon post, it works better for my aggressive position


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KGB
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Re: Zero offset seat posts on road bikes

Postby KGB » Mon Apr 07, 2014 12:47 pm

I have a Thomson on my track bike and commuter (flat bar roadie). Nice posts. Anything in the right diameter (and length) will be fine as mentioned.

The reason for layback posts is NOT marketing. Traditionally, road bikes were a bit longer and more relaxed than the modern roadie. Longer chainstays, wheelbase and a more relaxed seat tube. Putting the rider further behind the bottom bracket has the effect of engaging the hamstrings and glutes more during the pedals stroke. Better than a very upright/forwards position that relies heavily on your quads.

Thats the theory anyway. You need to use whatever components allow you to get the correct / best / most comfortable position etc.
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Mozzar
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Re: Zero offset seat posts on road bikes

Postby Mozzar » Mon Apr 07, 2014 12:57 pm

I wouldn't recommend a zero offset seat post on any bike. the problem with being to far forward is that you tend to push down on your pedals to much and on fast sections tend to push yourself out of your seat loosing any efficiency. the further back max 55mm is better as you push yourself back into your seat not out of your seat.

If you were meant to sit straight above your cranks/bb then they would have made the seat tube vertical rather then at an angle.

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mitchy_
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Re: Zero offset seat posts on road bikes

Postby mitchy_ » Mon Apr 07, 2014 1:01 pm

Mozzar wrote:I wouldn't recommend a zero offset seat post on any bike. the problem with being to far forward is that you tend to push down on your pedals to much and on fast sections tend to push yourself out of your seat loosing any efficiency. the further back max 55mm is better as you push yourself back into your seat not out of your seat.

If you were meant to sit straight above your cranks/bb then they would have made the seat tube vertical rather then at an angle.
firstly, that all depends on how long your legs are.
secondly, it also comes down to bike geometry... i have the same seat to stem measurement on 2 bikes, 1 with a straight and the other a setback post.

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biker jk
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Re: Zero offset seat posts on road bikes

Postby biker jk » Mon Apr 07, 2014 2:24 pm

mitchy_ wrote:
Mozzar wrote:I wouldn't recommend a zero offset seat post on any bike. the problem with being to far forward is that you tend to push down on your pedals to much and on fast sections tend to push yourself out of your seat loosing any efficiency. the further back max 55mm is better as you push yourself back into your seat not out of your seat.

If you were meant to sit straight above your cranks/bb then they would have made the seat tube vertical rather then at an angle.
firstly, that all depends on how long your legs are.
secondly, it also comes down to bike geometry... i have the same seat to stem measurement on 2 bikes, 1 with a straight and the other a setback post.
+ 1. I too have two bikes with the same saddle tip to bar measurement, one with a setback seatpost the other with zero setback.

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toolonglegs
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Re: Zero offset seat posts on road bikes

Postby toolonglegs » Mon Apr 07, 2014 3:55 pm

3 bikes with same saddle to bb position... 2 straight posts and one setback facing forward!. Big frames don't need more setback!.

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BrownBike
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Re: Zero offset seat posts on road bikes

Postby BrownBike » Mon Apr 07, 2014 4:24 pm

Well I have a big frame and long femurs. My saddle is most comfortable when I sit further back on it, and combined with poor lower back flexibility, the very thorough bike fitter (physio) recommended coming forward another 2cm. Due to saddle mechanics this can only be achieved with replacing setback seat post with straight one. Better solution would be slightly different frame geometry but a seat post will do in the meantime.

kenwstr
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Re: Zero offset seat posts on road bikes

Postby kenwstr » Thu Apr 10, 2014 11:38 pm

OK so I'm a Newb but I gather that road bikes can use a more forward saddle position for aggressive racing or a more rear or relaxed position for longer endurance. This is reflected in frame geometry angles but I guess you could override the frame geometry to some extent by choosing different seat post offsets. All this is going to change reach as well so if you want to retain the same reach but have a more aggressive position over the crank, I think you will need to swap in a longer stem. and that will make the steering less responsive. Also you could be a person with relatively short or long legs so you may wish to play with the reach in relation to the frame chosen on leg length. If you don't wan t to change the steering response, then you need to adjust saddle position and this may require a change in post offset to attain the correct adjustment. If the guy setting you is a track guy, he may be naturally inclined to go for the more aggressive forward saddle. So there is probably a question about whether the frame geometry suits your intended purpose. I think I'd start with that question.

What do I know, there is some fit info here: http://www.argonautcyclecoaching.com/?p ... calculator" onclick="window.open(this.href);return false;


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Ken

BriP
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Re: Zero offset seat posts on road bikes

Postby BriP » Sat Apr 12, 2014 11:29 am

mitchy_ wrote:
firstly, that all depends on how long your legs are.
secondly, it also comes down to bike geometry... i have the same seat to stem measurement on 2 bikes, 1 with a straight and the other a setback post.
yup agreed. my frame has a pretty relaxed geometry, so the zero setback compensated for the seat tube angle


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