Seatposts: straight vs. offset.

[DlphcOracl]

Can someone please explain when and why to select one type of seatpost over the other? Intuitively, it would seem as if the effect of an offset seatpost could be duplicated with a straight seatpost by simply moving the saddle a bit further back in its clamp? What am I missing here (seriously!!) ? Any coherent explanations would be appreciated, especially with regard to when choosing straight vs. offset seatposts is appropriate.

Thanks in advance.

[Wayne77]

1. Offset posts look better - they "flow" better with the lines of a bike.

2. A saddle pushed back on a straight post looks weird.

3. The idea is to make your seatpost NOT look like a sewer pipe being rammed into your nether regions. The "offsetedness" helps to alleviate this.

4. There's some gestalt-ish rationale for offset posts, but I'll leave that to the experts...



***IMO of course!!***

[Serpico]

how does an offset post affect weight balance and/or positioning re: relation between body over the wheels

are there any other reasons to use a setback post to achieve setback as opposed to using the seat tube angle (if you're getting a made to measure frame)



1. Offset posts look better - they "flow" better with the lines of a bike.

2. A saddle pushed back on a straight post looks wierd.

3. The idea is to make your seatpost NOT look like a sewer pipe being rammed into your nether regions. The "offsetedness" helps to alleviate this.

4. There's some gestalt-ish rationale for offset posts, but I'll leave that to the experts...



***IMO of course!!***

[Ray]

The saddle position is what affects weight/balance positioning over the wheels. Whatever combination of seat tube angle, setback (or not) post, and/or saddle position on the post you use makes no difference to position on the bike, comfort, efficiency, and weight distribution. A reason to go for a seat tube angle that allows a center rail placement of the saddle (again, affected by seatpost) is that the rails of the saddle aren't the exactly the STRONGEST tubes on the bike and shoving the saddle all the way back on the rails can lead to rail failures in some cases. OTOH, it may provide a small amount of suspension before they fail :)

Whether you achieve X position using a slacker STA and a straight post or a steeper STA and a setback post doesn't matter a bit unless you have an aesthetic preference.

Unless I'm wrong.

-Ray

[Tom]

Anybody have a suggestion for a good metal setback post?

[saab2000]

The only reason to choose one over the other is to achieve the desired position. Thomson seatposts are, IMHO, the best out there. But their setback version is butt ugly (their straight version isn't much better....) and doesn't achieve all that much setback.

Metal setback posts are on Ebay all the time: Campagnolo Record/Chorus titanium.

[Fat Robert]

about a year ago, i posted "straight posts are stupid and depraved" or something like that, just to see people's reactions. there was a mix of responses. it was fun. the short of it seemed to be:

* straight post effectively increases the STA by about 2-3 degrees, about a 2cm difference in saddle setback, which, according to some can yutz with the weight distribution, and ride quality. YMMV.

* straight post on a custom frame = ok if it was designed for it, dumb if it wasn't

* straight post is an ok compromise if the frame setback is so great that you need to use the straightie to get your saddle setback where it needs to be. some builders on the board raised the observation that if you have to use a straight post to achieve your desired saddle position, maybe that frame was not the best choice (or you're robbie mcewen and you had no choice).

let the designers/builders explain it better....

I really like the thompson setback, but it only has 16mm of offset. now that my back is better, I have my saddle shoved all the way back on mine...which is pretty much how you end up running that post...which looks cool on sloping tt bikes, which are ugly to begin with, so its an ugly gestalt thing.

steve p will ream me out now

[saab2000]

I picked up a Thomson setback on Ebay to replace my Campagnolo carbon for my Merckx. The carbon one bit the dust after 5 years.

I do get the desired position with the Thomson and that's the most important thing. Plus, it is strong and safe. Fugly, but functional.

Get the one that puts you in the right position.

[Fat Robert]

Plus, it is strong and safe. Fugly, but functional.
.


the ron jeremy of seatposts, eh?

[stevep]

.

steve p will ream me out now

only ream you out if necessary.
move on...

[Fat Robert]

only ream you out if necessary.
move on...


pleeeeeeeease?

[mwos]

I too, wonder why this is an issue.

In my case my femur is so short that even with a 74.5 st angle I need a zero degree seatpost to achieve the proper riding postion.

At least no one on this forum critized my seatpost or saddle position when they saw pictures of my Ottrott. :)

Kathi

[jeffg]

you are most often better served with setback though I have yet to get a frame that uses a setback post since mine were designed around a straight post since I prefer a Thomson post for functionality and the setback version is indeed fugy and reserved for my Cardgirus ergometer. I am, however, locked in to a straight seatpost on these frames and there are many more choices in setback posts since most frames are designed assuming a setback post, or so I am told.

I will likely have a new steed on the way sometime in 2007 that is designed around a setback post and the builder knows what he is doing, to say the least. Now if I can just find a good metal post in a 29.4 size and a 115mm stem ... I am thinking Bold precision for the first issue and a Newton (Europe) for the second ...

[Big Dan]

Find your position and use the seatpost that you need.......
I use both on different bikes............ :)

[rePhil]

Anybody have a suggestion for a good metal setback post?


My 3 road rides are all Campy with the exception of the seatposts. I really like the Dura Ace posts. I see they quit making them and I wonder why?
Same with the Campy Ti. I wanted to like them but they were all over the place with their measurements, but they are durable.

[dirtdigger88]

I really like the Dura Ace posts. I see they quit making them and I wonder why?


shimano still lists the post under their track (http://bike.shimano.com/catalog/cycle/products/group.jsp?FOLDER%3C%3Efolder_id=2534374302050541&ASSORTMENT%3C%3East_id=1408474395181674&bmUID=1167759828352) line

jason

[rePhil]

I don't anticipate being in the market but ya never know.

[sbornia]

I really like the thompson setback, but it only has 16mm of offset.

Anyone know how much setback is in other common posts like the current Campy, Ritchey, etc? I have the Thomson on three bikes, but am curious about others.