Exceeding torque specs on seatpost clamp

[Lou D'Amelio]

Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
spec (16 N-m) and even a little beyond. This is on a 'cross bike and
the clamp slides back tilting the saddle up with the normal jostling
of an hour training or a 45 minute race. Aside from the obvious (crank
the hell out of the bolts and hope they don't snap altogether) is
there anything I can apply to the undersurface of the clamp to help
this ? It's an aluminum post; I specifically avoided carbon to keep
low-tech and avoid problems like this.

Thanks........Lou D'Amelio

 

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

On Sep 30, 5:14 am, Lou D'Amelio <[email protected]> wrote:
> Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
> spec (16 N-m) and even a little beyond. This is on a 'cross bike and
> the clamp slides back tilting the saddle up with the normal jostling
> of an hour training or a 45 minute race. Aside from the obvious (crank
> the hell out of the bolts and hope they don't snap altogether) is
> there anything I can apply to the undersurface of the clamp to help
> this ? It's an aluminum post; I specifically avoided carbon to keep
> low-tech and avoid problems like this.
>
> Thanks........Lou D'Amelio

Smooth surfaces in the clamp are not the greatest thing for
'cross..with the dismount, remount gig going on. You can try to
roughen up the surfaces or get a SP that has 'notches', or one with
fore-aft mounting bolts like Thompson.

 

[[email protected]]

On Sep 30, 6:14 am, Lou D'Amelio <[email protected]> wrote:
> Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
> spec (16 N-m) and even a little beyond. This is on a 'cross bike and
> the clamp slides back tilting the saddle up with the normal jostling
> of an hour training or a 45 minute race. Aside from the obvious (crank
> the hell out of the bolts and hope they don't snap altogether) is
> there anything I can apply to the undersurface of the clamp to help
> this ? It's an aluminum post; I specifically avoided carbon to keep
> low-tech and avoid problems like this.
>
> Thanks........Lou D'Amelio

I've had good luck with automotive valve lapping compound on slipping
components. Probably wouldn't be a good idea on carbon, but it should
be OK on aluminum. I've used it on posts that wanted to keep slipping
down and it worked fine. You can get it at auto parts stores. If
you've ever got a buggered up philips head screw, try putting some on
the tip of the screwdriver before you try to turn it out.

Smokey

 

[[email protected]]

On Sep 30, 6:14 am, Lou D'Amelio <[email protected]> wrote:
> Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
> spec (16 N-m) and even a little beyond. This is on a 'cross bike and
> the clamp slides back tilting the saddle up with the normal jostling
> of an hour training or a 45 minute race. Aside from the obvious (crank
> the hell out of the bolts and hope they don't snap altogether) is
> there anything I can apply to the undersurface of the clamp to help
> this ? It's an aluminum post; I specifically avoided carbon to keep
> low-tech and avoid problems like this.
>
> Thanks........Lou D'Amelio

I've stopped seat posts from slipping (in the frame) by cleaning the
mating surfaces with acetone. Haven't tried it on a Ritchey seat post
head though.

The usual advice still applies about greasing the bolt shoulder, both
sides of any washers, and the threads, etc.

The Bontrager Race Lite seat post I use for 'cross has never slipped
on me. http://www.bontrager.com/Road/Components/Seatposts/22086.php

 

[Joel Mayes]

On 2007-09-30, Lou D'Amelio <[email protected]> wrote:
> Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
> spec (16 N-m) and even a little beyond. This is on a 'cross bike and
> the clamp slides back tilting the saddle up with the normal jostling
> of an hour training or a 45 minute race. Aside from the obvious (crank
> the hell out of the bolts and hope they don't snap altogether) is
> there anything I can apply to the undersurface of the clamp to help
> this ? It's an aluminum post; I specifically avoided carbon to keep
> low-tech and avoid problems like this.
>
> Thanks........Lou D'Amelio

I'm guessing you when the bolt which attachs the saddle to the seatpost?

Replace the bolts with high tensile (12.9 grade) M8 bolts and torque it
up, it you're worried about the hut stripping replace it too, or if it's
got a special shape drill it out and put in a good quality nuts.

Cheers

Joel

--
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[jim beam]

Lou D'Amelio wrote:
> Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
> spec (16 N-m) and even a little beyond. This is on a 'cross bike and
> the clamp slides back tilting the saddle up with the normal jostling
> of an hour training or a 45 minute race. Aside from the obvious (crank
> the hell out of the bolts and hope they don't snap altogether) is
> there anything I can apply to the undersurface of the clamp to help
> this ? It's an aluminum post; I specifically avoided carbon to keep
> low-tech and avoid problems like this.
>
> Thanks........Lou D'Amelio
>
and paradoxically, use of an ungreased carbon post would prevent slippage...

btw, it's almost certainly ok to increase torque on an aluminum post.
the spec you have is probably for a carbon post.

 

[Mark]

Lou D'Amelio wrote:
> Hi - new seatpost clamp (Ritchey WCS) slips when both bolts torqued to
> spec (16 N-m) and even a little beyond. This is on a 'cross bike and
> the clamp slides back tilting the saddle up with the normal jostling
> of an hour training or a 45 minute race. Aside from the obvious (crank
> the hell out of the bolts and hope they don't snap altogether) is
> there anything I can apply to the undersurface of the clamp to help
> this ? It's an aluminum post; I specifically avoided carbon to keep
> low-tech and avoid problems like this.
>
> Thanks........Lou D'Amelio
>

There's the Ritchey "liquid torque" stuff:
http://www.excelsports.com/new.asp?...tion=Liquid+Torque+5+grams&vendorCode=RITCHEY

I've no idea if it works.

I had a slippy alum-alum stem/bar joint that I was gonna try it on, but
lock-tite seems to be doing the trick so far. Dunno if I'm gonna regret
that later.

Mark J.