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-   -   Seatpost position? (https://www.bikeforums.net/road-cycling/1095955-seatpost-position.html)

mrmb 01-26-17 03:29 PM

Seatpost position?
 
I ride on roads and paved bike paths fairly frequently and I periodically see a guy ride by and he will have about 15inches of seatpost sticking out of his frame. Other times I will see other guys that have their saddle flush with the frame and no seatpost sticking out.

Makes me wonder....

Does no exposed seatpost indicate that the frame is too big and the rider compensated by bottoming out the seatpost? On the other hand, 15inches of of seatpost sticking out would indicate too small of a frame, right?

Myself, I always end up with about 4-8 inches of seatpost sticking out. Can't help but wonder about some of the other guys I see riding around with 15inches or none at all. I understand that as long as it works, it works, but....

RPK79 01-26-17 04:24 PM

Depends on the frame. Different geometries will yield different amounts of post.

For reference:

http://www.cyclingabout.com/wp-conte...14-1144-am.jpg

gsa103 01-26-17 05:52 PM

More flexible riders will typically have a seat post way up.

If the stem is flipped up with a stack of spacers AND the seatpost is way up, then the frame is too small. If the stem is down with a modest spacer or two underneath, then it's probably just a rider with long legs.

mcours2006 01-26-17 06:03 PM

2 Attachment(s)

Originally Posted by RPK79 (Post 19338562)
Depends on the frame. Different geometries will yield different amounts of post.

For reference:

http://www.cyclingabout.com/wp-conte...14-1144-am.jpg

The gravel, cx, and road look exactly the same to me.

I will say that of all my bikes the newest ones are the ones with more exposed seatpost. The steel road bike from the 1980's is the one with the shortest exposed post. Both are 54 cm.

Attachment 550397
Attachment 550398

Doge 01-26-17 06:41 PM

Top tubes slope at different amounts. A bigger slope means more post.
A good fit, is a good fit. The post height/leg extension may change a bit based on type of riding.
True, for seat in the same position more post/less post (and material and shape) does mean different ride, but there is no such thing as better riders have more or less post, only really bad fits where anything can be one extreme or the other.

ClydeTim 01-26-17 06:45 PM

On the straight top tube, the ball park reference was a handful of post between the saddle and frame. My bike complies.

On my sloping TT frame, there is much more.

I am surprised at how many cyclists I have come across that did not know there was a difference in top tubes.

RPK79 01-26-17 06:45 PM


Originally Posted by mcours2006 (Post 19338719)
The gravel, cx, and road look exactly the same to me.

Yes,I grabbed the first picture i saw with multiple geometry bikes in it.

Doge 01-26-17 07:02 PM

The fastest bikes do not have sloped top tubes - or round posts. But they will be a bit heavier.

datlas 01-26-17 07:29 PM


Originally Posted by ClydeTim (Post 19338832)
On the straight top tube, the ball park reference was a handful of post between the saddle and frame. My bike complies.

On my sloping TT frame, there is much more.

I am surprised at how many cyclists I have come across that did not know there was a difference in top tubes.

I thought the old "rule of thumb" for back-in-the-day frame styles was that the seatpost show should be roughly the same as the head tube length. Nowadays with compact and semi-compact frames, this is no longer a good reference. :50:

ClydeTim 01-26-17 08:04 PM


Originally Posted by datlas (Post 19338924)
I thought the old "rule of thumb" for back-in-the-day frame styles was that the seatpost show should be roughly the same as the head tube length. Nowadays with compact and semi-compact frames, this is no longer a good reference. :50:

Never heard that one but i look over at my bike and it looks true as well. :D

jon c. 01-26-17 08:51 PM

The amount of seat tube many road riders now show would have been seen as a sign of a frame that was too small back in the 70s.

Sy Reene 01-26-17 09:50 PM

you mean like this?
http://www.englishcycles.com/wp-cont...s_001_4584.jpg


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