When to change the seatpost ?

On Thu, 25 Sep 2008 19:50:21 -0700 (PDT), Jay Beattie
wrote:

On Sep 25, 6:30*pm, Tom Sherman
wrote:
Mike "Rocket J Squirrel" Elliot wrote:



On 9/25/2008 5:04 PM landotter wrote:

On Sep 26, 6:19 am, wrote:
When to change the seatpost ?
How many kilometer, years and terrible roads
is time to change my aluminum road seatpost
that came with my Giant Ocr1 2002

When it fails or develops cracks. You may also find that the branding
of the post leaves you depressed and upgrading to a name brand that is
prominently silkscreened on the side my give you a psychological
advantage. Your personal mass is also a variable.

This is all too vague. Couldn't the OP get the post sent out for fatigue
analysis?

As a minimum, the rider should do a daily dye penetrant inspection on
the seat post, with weekly radiographic inspection.

I got a great Chinese x-ray machine from Harbor Freight that I use
just for that. And with all the radiation spillage, I don't have to
shave my legs anymore -- or face, or cut my hair.

BTW, hasn't anyone ever broken a seatpost -- maybe a CF seatpost? I
broke the bolts on a 70's Weyless and a POS Avocet seatpost, but I
have never bent or broken an actual post.-- Jay Beattie.

Dear Jay,

Years ago, a seatpost broke under me about three minutes into my daily
ride. No crash, no drama, just riding along.

It looked as if the seatbag strap, combined with dried mud and road
grit, had sanded the post down until it failed.

Wish that I'd kept the pieces.

Cheers,

Carl Fogel

Back-in-the-day I broke an Avocet SP after sliding out in a corner on
a very wet and slick race course. 1979 Maryland Road Classic S I-II.
Anyway, I started to get going again, but ... Every component that I
had from Avocet failed. Back to Campy. Otherwise, I broke very few
other components and no other seat posts. I even had an Avocet front
hub body split after lacing it up TG they did not make stems.

On Sep 25, 10:50*pm, Jay Beattie wrote:
On Sep 25, 6:30*pm, Tom Sherman
wrote:





Mike "Rocket J Squirrel" Elliot wrote:

On 9/25/2008 5:04 PM landotter wrote:

On Sep 26, 6:19 am, wrote:
When to change the seatpost ?
How many kilometer, years and terrible roads
is time to change my aluminum road seatpost
that came with my Giant Ocr1 2002

When it fails or develops cracks. You may also find that the branding
of the post leaves you depressed and upgrading to a name brand that is
prominently silkscreened on the side my give you a psychological
advantage. Your personal mass is also a variable.

This is all too vague. Couldn't the OP get the post sent out for fatigue
analysis?

As a minimum, the rider should do a daily dye penetrant inspection on
the seat post, with weekly radiographic inspection.

I got a great Chinese x-ray machine from Harbor Freight that I use
just for that. *And with all the radiation spillage, I don't have to
shave my legs anymore -- or face, or cut my hair.

BTW, hasn't anyone ever broken a seatpost -- maybe a CF seatpost? *I
broke the bolts on a 70's Weyless and a POS Avocet seatpost, but I
have never bent or broken an actual post.-- Jay Beattie.- Hide quoted text -

- Show quoted text -

wrote:
When to change the seatpost ?
How many kilometer, years and terrible roads
is time to change my aluminum road seatpost
that came with my Giant Ocr1 2002

Denis


too vague to say. but you should replace them every once in a while.
if you're worried about breakage, carbon is much more fatigue resistant
than anything else, so, especially if you ride a long seat post, as a
giant compact frame would dictate, [quality] carbon would be the seat
post material of choice for you.

jim beam wrote:
wrote:
When to change the seatpost ?
How many kilometer, years and terrible roads
is time to change my aluminum road seatpost
that came with my Giant Ocr1 2002

Denis


too vague to say. but you should replace them every once in a while. if
you're worried about breakage, carbon is much more fatigue resistant
than anything else, so, especially if you ride a long seat post, as a
giant compact frame would dictate, [quality] carbon would be the seat
post material of choice for you.


i should add - the fatigue load on any seatpost increases with rider
weight and extension. the heavier the rider, the longer the post
extension and the worse the road, the more frequently the post should be
replaced.

On Sep 25, 7:50*pm, Jay Beattie wrote:

BTW, hasn't anyone ever broken a seatpost -- maybe a CF seatpost? *I
broke the bolts on a 70's Weyless and a POS Avocet seatpost, but I
have never bent or broken an actual post.-- Jay Beattie.

Never broken one, but I bent the stock no-name seatpost that came on
my '03 GT Avalanche 1.0 about a month after I got the bike. Granted,
I weighed about 290 at the time. Replaced it with a Kalloy Uno
(rebadged as a "Weyless" by Supergo, who bought the name) and never
had any more problems with bending.

I've broken the bolts on two seatposts (different manufacturers, not
stupid light) over the years.

I'd say that a few thousand hours of use (maybe 3 or 4K hours) it's
important to at least inspect the post and bolts carefully.

Jay Beattie wrote:
On Sep 25, 6:30 pm, Tom Sherman
wrote:
Mike "Rocket J Squirrel" Elliot wrote:



On 9/25/2008 5:04 PM landotter wrote:
On Sep 26, 6:19 am, wrote:
When to change the seatpost ?
How many kilometer, years and terrible roads
is time to change my aluminum road seatpost
that came with my Giant Ocr1 2002
When it fails or develops cracks. You may also find that the branding
of the post leaves you depressed and upgrading to a name brand that is
prominently silkscreened on the side my give you a psychological
advantage. Your personal mass is also a variable.
This is all too vague. Couldn't the OP get the post sent out for fatigue
analysis?
As a minimum, the rider should do a daily dye penetrant inspection on
the seat post, with weekly radiographic inspection.

I got a great Chinese x-ray machine from Harbor Freight that I use
just for that. And with all the radiation spillage, I don't have to
shave my legs anymore -- or face, or cut my hair.

BTW, hasn't anyone ever broken a seatpost -- maybe a CF seatpost? I
broke the bolts on a 70's Weyless and a POS Avocet seatpost, but I
have never bent or broken an actual post.-- Jay Beattie.

4-5 years ago one of the Pros nearly bled to death after being sliced
open by a failed magic material post on a training ride.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **

On Sep 26, 5:18*am, John Forrest Tomlinson
wrote:
I've broken the bolts on two seatposts (different manufacturers, not
stupid light) over the years.

I'd say that a few thousand hours of use (maybe 3 or 4K hours) it's
important to at least inspect the post and bolts carefully.

At a minimum, remove, recoat, reinstall every 6 months to prevent
electrolytic welding between the steel seat post tube and the aluminum
seat post.

On Sep 25, 6:19*pm, wrote:
When to change the seatpost ?
How many kilometer, years and terrible roads
is time to change my aluminum road seatpost
that came with my Giant Ocr1 2002

Denis

I've been abusing the same aluminum frame for over 10 years on my
MTB. The seat post... not sure if I ever replaced it. If i did, it
was because it bent, not because I thought it was time in years or
hours of use.

Jay Beattie wrote:

BTW, hasn't anyone ever broken a seatpost -- maybe a CF seatpost? *I
broke the bolts on a 70's Weyless and a POS Avocet seatpost, but I
have never bent or broken an actual post.

I have not broken any posts, but I have bent far more of them than I
could ever keep track of.

Most of them were overhung from the frame more than the average post,
but none of them were extended past the "MAX HT" line.

Chalo