Seatpost Clamp

[Rob Lindauer]

Well, this is probably a pretty silly question - but here goes anyway...

I want to make sure I know the correct way to fit my seatpost clamp
(since, although the clamp is tight - I can't twist the seat - my
seatpost gradually descends a couple mm per day)...

I have an aluminum frame Specialized Sirrus Pro. The seatpost clamp is
a slotted aluminum ring, stamped 32, with a ridge around the inside on
what I take to be the top.

I presume the clamp fits over the seat tube, with the ridge serving as a
stop to prevent the clamp from dropping down too far. In other words,
the ridge sits "above" the seat tube and doesn't squeeze the seat tube
per se (wthe larger-diameter lower part of the clamp does squeeze the
seat tube).

Do I have that right?

Thanks!
--
Rob Lindauer - Please change "att" to "sbc" for my real email address

[Tom Kunich]

"Rob Lindauer" <rlindx@attglobal.net> wrote in message
news:M__0k.2429$ZE5.1304@nlpi061.nbdc.sbc.com...
> Well, this is probably a pretty silly question - but here goes anyway...
>
> I want to make sure I know the correct way to fit my seatpost clamp
> (since, although the clamp is tight - I can't twist the seat - my seatpost
> gradually descends a couple mm per day)...
>
> I have an aluminum frame Specialized Sirrus Pro. The seatpost clamp is a
> slotted aluminum ring, stamped 32, with a ridge around the inside on what
> I take to be the top.
>
> I presume the clamp fits over the seat tube, with the ridge serving as a
> stop to prevent the clamp from dropping down too far. In other words, the
> ridge sits "above" the seat tube and doesn't squeeze the seat tube per se
> (wthe larger-diameter lower part of the clamp does squeeze the seat tube).
>
> Do I have that right?

Yes you have it correct. I would think that your seatpost is carbon fiber.
This stuff is too slick for this sort of locking mechanism. I have the same
problem on my Time VX. You can solve the problem by buying a Shimano,
Thompson or some other aluminum seatpost which will probably be lighter and
won't slide down after proper tightening.

[Bill Sornson]

Rob Lindauer wrote:
> Well, this is probably a pretty silly question - but here goes
> anyway...
> I want to make sure I know the correct way to fit my seatpost clamp
> (since, although the clamp is tight - I can't twist the seat - my
> seatpost gradually descends a couple mm per day)...
>
> I have an aluminum frame Specialized Sirrus Pro. The seatpost clamp
> is a slotted aluminum ring, stamped 32, with a ridge around the
> inside on what I take to be the top.
>
> I presume the clamp fits over the seat tube, with the ridge serving
> as a stop to prevent the clamp from dropping down too far. In other
> words, the ridge sits "above" the seat tube and doesn't squeeze the
> seat tube per se (wthe larger-diameter lower part of the clamp does
> squeeze the seat tube).
>
> Do I have that right?

Yes. If you're getting slippage, try wiping the post almost dry (a little
grease is OK) and tightening the clamp a bit more. I wrap a layer of
plumber's tape around the post sometimes; and you can also use a plastic
"blinkie" mount to help add resistance to the post slipping. (Tighten it
good with a rubber bumper; worst that will happen is the plastic breaks.)

Finally, of course, you can always rough up the post surface a little, but
that can lead to it galvanizing with the frame eventually (theorizing
allowed 'cuz I said so).

Bill "gorilla's touch" S.

[Michael Press]

In article <M__0k.2429$ZE5.1304@nlpi061.nbdc.sbc.com>,
Rob Lindauer <rlindx@attglobal.net> wrote:

> Well, this is probably a pretty silly question - but here goes anyway...
>
> I want to make sure I know the correct way to fit my seatpost clamp
> (since, although the clamp is tight - I can't twist the seat - my
> seatpost gradually descends a couple mm per day)...
>
> I have an aluminum frame Specialized Sirrus Pro. The seatpost clamp is
> a slotted aluminum ring, stamped 32, with a ridge around the inside on
> what I take to be the top.
>
> I presume the clamp fits over the seat tube, with the ridge serving as a
> stop to prevent the clamp from dropping down too far. In other words,
> the ridge sits "above" the seat tube and doesn't squeeze the seat tube
> per se (wthe larger-diameter lower part of the clamp does squeeze the
> seat tube).
>
> Do I have that right?

Yes. One refinement is to rotate the clamp so that the
slot on the clamp is half a revolution away from the
slot in the seat tube. This almost certainly will _not_
fix your current difficulty, but is worth doing.

--
Michael Press

[Werehatrack]

On Mon, 02 Jun 2008 19:03:05 -0400, Rob Lindauer
<rlindx@attglobal.net> may have said:

>Well, this is probably a pretty silly question - but here goes anyway...
>
>I want to make sure I know the correct way to fit my seatpost clamp
>(since, although the clamp is tight - I can't twist the seat - my
>seatpost gradually descends a couple mm per day)...
>
>I have an aluminum frame Specialized Sirrus Pro. The seatpost clamp is
>a slotted aluminum ring, stamped 32, with a ridge around the inside on
>what I take to be the top.
>
>I presume the clamp fits over the seat tube, with the ridge serving as a
>stop to prevent the clamp from dropping down too far. In other words,
>the ridge sits "above" the seat tube and doesn't squeeze the seat tube
>per se (wthe larger-diameter lower part of the clamp does squeeze the
>seat tube).
>
>Do I have that right?

Yes. Additionally, the seatpost clamp may need just a tiny amount of
grease between it and the frame in order to achieve a tight grip.


--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

[Qui si parla Campagnolo-www.vecchios.com]

On Jun 2, 5:03*pm, Rob Lindauer <rli...@attglobal.net> wrote:
> Well, this is probably a pretty silly question - but here goes anyway...
>
> I want to make sure I know the correct way to fit my seatpost clamp
> (since, although the clamp is tight - I can't twist the seat - my
> seatpost gradually descends a couple mm per day)...
>
> I have an aluminum frame Specialized Sirrus Pro. *The seatpost clamp is
> a slotted aluminum ring, stamped 32, with a ridge around the inside on
> what I take to be the top.
>
> I presume the clamp fits over the seat tube, with the ridge serving as a
> stop to prevent the clamp from dropping down too far. *In other words,
> the ridge sits "above" the seat tube and doesn't squeeze the seat tube
> per se (wthe larger-diameter lower part of the clamp does squeeze the
> seat tube).
>
> Do I have that right?
>
> Thanks!
> --
> Rob Lindauer - Please change "att" to "sbc" for my real email address

Yes and if the seatpost is aluminum, go to a good bike shop and have
the seatpost 'knurled' with a tool that adds ridges to thew post,
preventing it from slipping.

[Rob Lindauer]

Tom Kunich wrote:

>
> Yes you have it correct. I would think that your seatpost is carbon
> fiber. This stuff is too slick for this sort of locking mechanism. I
> have the same problem on my Time VX. You can solve the problem by buying
> a Shimano, Thompson or some other aluminum seatpost which will probably
> be lighter and won't slide down after proper tightening.
>

Thanks, Tom. It's an older, less sophisticated, with aluminum seatpost
and frame. It would appear I just need to snug the clamp a bit more
(but I'll also check with the shop or manufacturer that the clamp I have
is indeed the right size). Thanks again, Rob L


--
Rob Lindauer - Please change "att" to "sbc" for my real email address

[Tom Kunich]

"Rob Lindauer" <rlindx@attglobal.net> wrote in message
news:Gf%0k.6358$Ri.5214@flpi146.ffdc.sbc.com...
> Tom Kunich wrote:
>
>>
>> Yes you have it correct. I would think that your seatpost is carbon
>> fiber. This stuff is too slick for this sort of locking mechanism. I have
>> the same problem on my Time VX. You can solve the problem by buying a
>> Shimano, Thompson or some other aluminum seatpost which will probably be
>> lighter and won't slide down after proper tightening.
>
> Thanks, Tom. It's an older, less sophisticated, with aluminum seatpost
> and frame. It would appear I just need to snug the clamp a bit more (but
> I'll also check with the shop or manufacturer that the clamp I have is
> indeed the right size). Thanks again, Rob L

Once in awhile you discover that the person who installed the seatpost
greased it. Simply cleaning the grease off and reinstallation in a cleaned
out seattube would cure that problem.

[Werehatrack]

On Tue, 03 Jun 2008 07:33:59 -0700, Michael Press <rubrum@pacbell.net>
may have said:

>In article <M__0k.2429$ZE5.1304@nlpi061.nbdc.sbc.com>,
> Rob Lindauer <rlindx@attglobal.net> wrote:
>
>> Well, this is probably a pretty silly question - but here goes anyway...
>>
>> I want to make sure I know the correct way to fit my seatpost clamp
>> (since, although the clamp is tight - I can't twist the seat - my
>> seatpost gradually descends a couple mm per day)...
>>
>> I have an aluminum frame Specialized Sirrus Pro. The seatpost clamp is
>> a slotted aluminum ring, stamped 32, with a ridge around the inside on
>> what I take to be the top.
>>
>> I presume the clamp fits over the seat tube, with the ridge serving as a
>> stop to prevent the clamp from dropping down too far. In other words,
>> the ridge sits "above" the seat tube and doesn't squeeze the seat tube
>> per se (wthe larger-diameter lower part of the clamp does squeeze the
>> seat tube).
>>
>> Do I have that right?
>
>Yes. One refinement is to rotate the clamp so that the
>slot on the clamp is half a revolution away from the
>slot in the seat tube. This almost certainly will _not_
>fix your current difficulty, but is worth doing.

Grease the interface between the two when using this technique; this
method minimizes the chance that the frame's tube will be distorted by
the clamp, but it also can reduce the effectiveness of the clamp if
the surfaces aren't lubricated.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

[Rob Lindauer]

My thanks to all for your replies / assistance. -RL

--
Rob Lindauer - Please change "att" to "sbc" for my real email address