# Offset seat post?



## Ventura Roubaix (Oct 10, 2009)

What are some reasons for using a offset seat post or what benefits are there in using one.


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## Ventruck (Mar 9, 2009)

It basically there to offer more rearward positioning, which is a case within itself upon being ideal for each specific rider. Most people seem to work with offset posts, as noticed by how they seem to be the common offering with most bikes. The case of using a non-offset post is usually presuming the rider has short femurs and can't get a good position relative to the pedals (not handlebar, as that's a matter of frame and stem sizing).

So in short, it's a measure to get the best fit on the bike. But you'd need decent analysis to know what offset you surely need.


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## C-40 (Feb 4, 2004)

*info...*



Ventura Roubaix said:


> What are some reasons for using a offset seat post or what benefits are there in using one.


Setback posts have been the norm for a very long time - like 30-40 years. Riders could achieve the same position with a nonsetback model, but the STA would have to be about 2 degrees less and the chainstays longer, so the tire wouldn't hit the seat tube.

Femur length is only relevant if you're a believer in the KOP school of bike fitting. A lot of well respected fitters do not use KOP at all. They fit the rider based mainly on weight balance over the saddle. If you have short femurs, KOP is likely to put you in a position with far too much weight on your hands. The ignorant fitter solves that problem by raising the bar height, so you end up with an unnecessarily upright position.


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## Ventura Roubaix (Oct 10, 2009)

Well the problem I seem to have is that I'm a long upper torso type guy, I'm 6'2" and wear 32"
inseam pants. I'm riding a 58cm Specialized Roubaix. I recently had a fit done, one of the things the fitter did was go from a 110 to 130 stem and push my seat back almost as far as it would go on the rails, this did help some with some chafing issues. But I still fill a little cramp like my knees are a little to far over the pedal axle plus my sit bones hurt me on rides over 15 mi. I ride mostly on the brake hoods. I find myself sliding back on the saddle to get a better weight balance to relieve some pressure on my sit bones, I run my saddle about level, I've got to make this frame size work as best as possible. I can't afford a larger frame.


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## C-40 (Feb 4, 2004)

*more...*

It's the STA that affects the setback, not the frame size, but a larger frame sometimes has a little more slack STA. If the reach is still too short, try a 140mm stem or bars with more reach.

Look for a seatpost with more setback. FSA makes a 32mm setback and there are others in the 40-45mm range.

Saddle choice can be another problem. Some have short rails that don't allow much setback.


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## Ventura Roubaix (Oct 10, 2009)

C-40 said:


> It's the STA that affects the setback, not the frame size, but a larger frame sometimes has a little more slack STA. If the reach is still too short, try a 140mm stem or bars with more reach.
> 
> Look for a seatpost with more setback. FSA makes a 32mm setback and there are others in the 40-45mm range.
> 
> Saddle choice can be another problem. Some have short rails that don't allow much setback.


I guess what I'm asking, would a setback seatpost help me get a better weight balance, between the seat and hoods, I'm using a Romin seat, its works great for no numbness issues but it causes my sit bones to hurt I don't know if this is a seat issue or a poor fit, or setup. I'm trying to pinpoint what causing the pressure point issue with my sitbones. I have about 500 mi on this seat.


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## Ventruck (Mar 9, 2009)

What post are you running? I'm assuming it's a supplied Specialized post that has some setback, like 21mm tops.

That being said there would exist seatposts that have more setback, many with a 25mm offset, but I'm short of help in pointing you to anything that has more than that.


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## Ventura Roubaix (Oct 10, 2009)

Ventruck said:


> What post are you running? I'm assuming it's a supplied Specialized post that has some setback, like 21mm tops.
> 
> That being said there would exist seatposts that have more setback, many with a 25mm offset, but I'm short of help in pointing you to anything that has more than that.


I don't really know, it a factory carbon post the spec sheet saids it a (Specialized Pave II, Fact carbon w/zertz insert, alum head 27.2mm). It looks fairly straight compare to the setback posts. The clamps set center over the top of the post.


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## eflayer2 (Feb 15, 2002)

*a good fitter*

should be able to answer your questions, or work with you over time to solve the problems. as you can see, changing too many things at one time makes it nearly impossible to nail down the solution(s). it's complicated.

go see steve rex in sacramento, ca.


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