Replace Thomson seatpost

[Frank121]

I was doing some routine maintenance today on the bike. When I was taking the seatpost out and
re-greasing it, I felt a mild indention on either side of the post. Looks like this is where the
seatpost has been clamped in the seattube on either side of the seatpost. No break, but enough of a
difference I could feel the difference when I ran my finger down the sides.

Anything to worry about? Time to replace the seatpost?

Thanks,

Frank

 

[Mike Jacoubowsk]

> I was doing some routine maintenance today on the bike. When I was taking the seatpost out and
> re-greasing it, I felt a mild indention on either
side
> of the post. Looks like this is where the seatpost has been clamped in the seattube on either side
> of the seatpost. No break, but enough of a difference I could feel the difference when I ran my
> finger down the
sides.

I'm surprised to hear of a Thompson seatpost having an issue like that; is it possible that someone
severely overtightened the seat collar? In any event, I'd bring it in to a shop to see what they
think, and if no undue force was applied, it's possible Thompson might consider it a warranty issue.
They're very good people, making very good seatposts.

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

 

[Frank121]

It may have been tightened too much as a torque wrench wasn't used on it. I don't think it came this
way...none of my others have.

Frank

"Mike Jacoubowsky" <[email protected]> wrote in message
news:dp%[email protected]...
> > I was doing some routine maintenance today on the bike. When I was
taking
> > the seatpost out and re-greasing it, I felt a mild indention on either
> side
> > of the post. Looks like this is where the seatpost has been clamped in
the
> > seattube on either side of the seatpost. No break, but enough of a difference I could feel the
> > difference when I ran my finger down the
> sides.
>
> I'm surprised to hear of a Thompson seatpost having an issue like that; is it possible that
> someone severely overtightened the seat collar? In any event, I'd bring it in to a shop to see
> what they think, and if no undue force was applied, it's possible Thompson might consider it a
> warranty issue. They're very good people, making very good seatposts.
>
> --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

 

[Jonathan Bond]

A seatpost collar is not something you really need to use a torque wrench on. Rule of thumb: if it
slides or slips, its too loose. Once you get it just tight enough to not do any of the above
(barring crashes and whatnot), then you're in the clear. If you have to crank it way way down to
keep it from slipping, either your collar is not too great, frame tolerences aren't too great, or
the seatpost is the wrong size.

Jon Bond

frank121 wrote:
> It may have been tightened too much as a torque wrench wasn't used on it. I don't think it came
> this way...none of my others have.
>
> Frank
>
> "Mike Jacoubowsky" <[email protected]> wrote in message
> news:dp%[email protected]...
>
>>>I was doing some routine maintenance today on the bike. When I was
>>
> taking
>
>>>the seatpost out and re-greasing it, I felt a mild indention on either
>>
>>side
>>
>>>of the post. Looks like this is where the seatpost has been clamped in
>>
> the
>
>>>seattube on either side of the seatpost. No break, but enough of a difference I could feel the
>>>difference when I ran my finger down the
>>
>>sides.
>>
>>I'm surprised to hear of a Thompson seatpost having an issue like that; is it possible that
>>someone severely overtightened the seat collar? In any event, I'd bring it in to a shop to see
>>what they think, and if no undue force was applied, it's possible Thompson might consider it a
>>warranty issue. They're very good people, making very good seatposts.
>>
>>--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
>>
>>
>

 

[David Kunz]

frank121 wrote:
> I was doing some routine maintenance today on the bike. When I was taking the seatpost out and
> re-greasing it, I felt a mild indention on either side of the post. Looks like this is where the
> seatpost has been clamped in the seattube on either side of the seatpost. No break, but enough of
> a difference I could feel the difference when I ran my finger down the sides.
>
> Anything to worry about? Time to replace the seatpost?
>
> Thanks,
>
> Frank
>

It could be that your seat clamp is mismatched to your bike. The clamp has a ring/ridge around the
top to keep it from sliding down the seatpost tube. If this ring is coming into contact with the
seatpost, it'll crimp it like you describe because it won't tighten properly over the whole friction
area -- just at the ring. Tompson MAY replace it if this has happened. My Tompson cracked in one of
the thin areas and collapsed slightly when I tightened it to make up for the fact that it was now
not holding. They replaced it, but sent me a tech note explaining the above and saying that they
would not consider that kind of damage a warranty return. I believe that it's also mentioned in the
installation instructions (that EVERYONE reads ).

David

 

[Klydesdale]

"David Kunz" <[email protected]> wrote in message
news:[email protected]...
> frank121 wrote:
> > I was doing some routine maintenance today on the bike. When I was
taking
> > the seatpost out and re-greasing it, I felt a mild indention on either
side
> > of the post. Looks like this is where the seatpost has been clamped in
the
> > seattube on either side of the seatpost. No break, but enough of a difference I could feel the
> > difference when I ran my finger down the
sides.
> >
> > Anything to worry about? Time to replace the seatpost?
> >
> > Thanks,
> >
> > Frank
> >
>
> It could be that your seat clamp is mismatched to your bike. The clamp has a ring/ridge around the
> top to keep it from sliding down the seatpost tube. If this ring is coming into contact with the
> seatpost, it'll crimp it like you describe because it won't tighten properly over the whole
> friction area -- just at the ring. Tompson MAY replace it if this has happened. My Tompson cracked
> in one of the thin areas and collapsed slightly when I tightened it to make up for the fact that
> it was now not holding. They replaced it, but sent me a tech note explaining the above and saying
> that they would not consider that kind of damage a warranty return. I believe that it's also
> mentioned in the installation instructions (that EVERYONE reads ).
>

Yeah, but did Thomson also mention that they design and manufacture their seatposts such that, if
anything, the seatpost will be smaller than the nominal diameter. This means that in some frames,
the post may be a sloppy fit and when you clamp down on it to keep it from slipping, you can end up
with the indentations described above. I had a 27.2mm Thomson post that I couldn't keep from
slipping in two different frames no matter what I did. I had used three or four other 27.2 posts in
these frame with no slippage (bending was the issue with them). The Thomson post was the loosest fit
of the lot so I contacted Thomson. They told me their design and manufacturing tolerances and when I
measured my seatpost with a micrometer, it's diameter was right at the small end of the tolerance
stack-up. To their credit, Thomson sent me another post that was closer to nominal diameter and that
fixed the issue

 

[Paul Southworth]

In article <[email protected]>, frank121 <[email protected]> wrote:
>I was doing some routine maintenance today on the bike. When I was taking the seatpost out and
>re-greasing it, I felt a mild indention on either side of the post. Looks like this is where the
>seatpost has been clamped in the seattube on either side of the seatpost. No break, but enough of a
>difference I could feel the difference when I ran my finger down the sides.
>
>Anything to worry about? Time to replace the seatpost?

Well that certainly increases the risk that you will bend or fold it over, but whether that happens
depends a lot on your weight and riding style.

Since you seem to buy a new road frame once a week, maybe you can find one that lets you insert the
post a little further and get the crimped portion into the seat tube.

My guess is either the seatpost is not exactly the right size or the clamp was overtightened.

--Paul

 

[Frank121]

Paul wrote..."Since you seem to buy a new road frame once a week, maybe you can find one that lets
you insert the post a little further and get the crimped portion into the seat tube. "

Hey, I resemble that remark!!!! ;-) I am sending the seat post to Thomson to have them take a look.
My guess is I overtightened the seatpost with the seat post binder clamp.

Frank

 

[Dave Thompson]

> Paul wrote..."Since you seem to buy a new road frame once a week, maybe
you
> can find one that lets you insert the post a little further and get the crimped portion into the
> seat tube. "
>
>
> Hey, I resemble that remark!!!! ;-) I am sending the seat post to Thomson
to
> have them take a look. My guess is I overtightened the seatpost with the seat post binder clamp.
>
> Frank

Frank, you could use that seatpost to build up your Atlanta!

Love, Dave