Carbon steerer problems... eek do I need a new fork?

[Mark]

Hi

Well, i have a nice Look HSC5 SL all carbon forks - beautiful....

Except, a while ago, they came a bit loose in my integrated headtube.
Now, I think i probably made a few errors from here on:

Firstly, it seemed to me that I couldn't get the cap tight enough to
get rid of all the play before the expander started moving in the
steerer. So, i purchased another bung...

Now, I didn't really appreciate that a major part of the bung is the
expand not just to grip the inside of the steerer so one can tighten
the cap and remove play, but also to re-enforce the inside of the
steerer around where the stem sits to stop damage caused by
overtightening the stem.

So, stupidly had the bung too far dow the steerer (slightly below the
bottom of the stem), so when I tightened the stem, the top of the two
bolts just kept tightening.

So, now, when I take the stem off and look at the top of the steerer,
I can see that I've sort of dented and slightly squashed the top of
the steerer.

So, I think I've partially rectified the problem by getting a bung
that grips right at the top of the steerer, within the boundaries of
the stem, but it's left me worried - I've almost certainly weakened
the top of my steerer.

I have a long stem anyhow - three 1cm spacers above the headtube, but
I really don't want to cut the steerer down by one of these spacers
(i.e. potentially to a less damaged part of the steerer), because it
will be too low for me.

I've tried to test how strong the stem/steerer join is by gripping the
handlebars when the bike's stationary and putting pressure on the join
(more pressure than I would imagine in normal use), and it all seems
strong.

It's an awkward one - a new pair of forks is about £230, which I'd
much rather not spend... but I don't want to have my bars break off at
30mph either

Well, advice would be most appreciated,

Many thanks,
Mark.

 

[Simon Brooke]

in message <[email protected]>, Mark
('[email protected]') wrote:

> Well, i have a nice Look HSC5 SL all carbon forks - beautiful....
>
> So, now, when I take the stem off and look at the top of the steerer,
> I can see that I've sort of dented and slightly squashed the top of
> the steerer.
>
> So, I think I've partially rectified the problem by getting a bung
> that grips right at the top of the steerer, within the boundaries of
> the stem, but it's left me worried - I've almost certainly weakened
> the top of my steerer.
>
> It's an awkward one - a new pair of forks is about £230, which I'd
> much rather not spend... but I don't want to have my bars break off at
> 30mph either
>
> Well, advice would be most appreciated,

I would seek advice directly from Look - they have a reputation of being
approachable and helpful, although I haven't dealt with them personally. I
expect getting your letter or email translated into French might help!

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

((DoctorWho)ChristopherEccleston).act();
uk.co.bbc.TypecastException: actor does not want to be typecast.
[adapted from autofile on /., 31/03/05]

 

[Mark]

> I've tried to test how strong the stem/steerer join is by gripping the
> handlebars when the bike's stationary and putting pressure on the join
> (more pressure than I would imagine in normal use), and it all seems
> strong.

Is it just the top of the steerer that's damaged? If so I can't see that causing a problem
further down the steerer. I'm just some bloke on Usenet thobut, and I won't be riding it
at 30+mph

> It's an awkward one - a new pair of forks is about £230, which I'd
> much rather not spend... but I don't want to have my bars break off at
> 30mph either

They'd look pretty mounted on a wall or, if it's a 1" steerer, I'll give you a tenner for
'em - I'm riding on an 11 year old carbon frame and my friends think it's only a matter of
time before the entire thing disintegrates beneath me - a dodgy fork won't worsen the odds
too much :-/

 

[Mark]

On 4 Aug, 20:46, Mark
<pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
wrote:
> > I've tried to test how strong the stem/steerer join is by gripping the
> > handlebars when the bike's stationary and putting pressure on the join
> > (more pressure than I would imagine in normal use), and it all seems
> > strong.
>
> Is it just the top of the steerer that's damaged? If so I can't see thatcausing a problem
> further down the steerer. I'm just some bloke on Usenet thobut, and I won't be riding it
> at 30+mph
>
> > It's an awkward one - a new pair of forks is about £230, which I'd
> > much rather not spend... but I don't want to have my bars break off at
> > 30mph either
>
> They'd look pretty mounted on a wall or, if it's a 1" steerer, I'll give you a tenner for
> 'em - I'm riding on an 11 year old carbon frame and my friends think it'sonly a matter of
> time before the entire thing disintegrates beneath me - a dodgy fork won't worsen the odds
> too much :-/

Ha ha guess you've gotta have a good sense of humour to be riding a
11 year old carbon frame

 

[Simon Brooke]

in message <[email protected]>, Mark
('[email protected]') wrote:

> On 4 Aug, 20:46, Mark
> <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
> wrote:
>> > I've tried to test how strong the stem/steerer join is by gripping the
>> > handlebars when the bike's stationary and putting pressure on the join
>> > (more pressure than I would imagine in normal use), and it all seems
>> > strong.
>>
>> Is it just the top of the steerer that's damaged? If so I can't see
>> that causing a problem
>> further down the steerer. I'm just some bloke on Usenet thobut, and I
>> won't be riding it at 30+mph
>>
>> > It's an awkward one - a new pair of forks is about £230, which I'd
>> > much rather not spend... but I don't want to have my bars break off at
>> > 30mph either
>>
>> They'd look pretty mounted on a wall or, if it's a 1" steerer, I'll give
>> you a tenner for 'em - I'm riding on an 11 year old carbon frame and my
>> friends think it's only a matter of time before the entire thing
>> disintegrates beneath me - a dodgy fork won't worsen the odds too much
>> :-/
>
> Ha ha guess you've gotta have a good sense of humour to be riding a
> 11 year old carbon frame

Why? Would you have a problem flying on an eleven year old carbon fibre
aeroplane? If so, you'd better not fly; all modern airliners use
significant elements of carbon fibre in their structure. If not, why do
you think structural failure on a pushbike is more serious than structural
failure on an aeroplane?

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; If you're doing this for fun, do what seems fun. If you're
;; doing it for money, stop now.
;; Rainer Deyke

 

[M-gineering]

Simon Brooke wrote:

> Why? Would you have a problem flying on an eleven year old carbon fibre
> aeroplane? If so, you'd better not fly; all modern airliners use
> significant elements of carbon fibre in their structure. If not, why do
> you think structural failure on a pushbike is more serious than structural
> failure on an aeroplane?
>

I wouldn't want to be close to an aeroplane built by 'bicycle engineers
'*) let alone fly in one



*) all QC performed by the paying customer
--
/Marten

info(apestaartje)m-gineering(punt)nl

 

[Tony B]

M-gineering wrote:

> *) all QC performed by the paying customer

a bit like aeroplanes then or pressure vessels or (topical)
bridges.... although mostly in the distant past.

T

 

[Roger Merriman]

Mark <[email protected]> wrote:

> On 4 Aug, 20:46, Mark
> <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
> wrote:
> > > I've tried to test how strong the stem/steerer join is by gripping the
> > > handlebars when the bike's stationary and putting pressure on the join
> > > (more pressure than I would imagine in normal use), and it all seems
> > > strong.
> >
> > Is it just the top of the steerer that's damaged? If so I can't see
> > that causing a problem further down the steerer. I'm just some bloke on
> > Usenet thobut, and I won't be riding it at 30+mph
> >
> > > It's an awkward one - a new pair of forks is about £230, which I'd
> > > much rather not spend... but I don't want to have my bars break off at
> > > 30mph either
> >
> > They'd look pretty mounted on a wall or, if it's a 1" steerer, I'll give
> > you a tenner for 'em - I'm riding on an 11 year old carbon frame and my
> > friends think it's only a matter of time before the entire thing
> > disintegrates beneath me - a dodgy fork won't worsen the odds too much
> > :-/
>
> Ha ha guess you've gotta have a good sense of humour to be riding a
> 11 year old carbon frame

i think i'd be more worried by a alui frame though probably not enought
to to ride it. as simon says planes use carbon, and they normally have
long working lives.

i don't think that carbon gets fractued like alu does so it shouldn't
degrade in that way though it doesn't like impacts nor sun i'd guess.

roger
--
www.rogermerriman.com

 

[Mark]

> i don't think that carbon gets fractued like alu does so it shouldn't
> degrade in that way though it doesn't like impacts nor sun i'd guess.

I forgot to mention the crash damage...

 

[Mark]

On 5 Aug, 13:00, Simon Brooke <[email protected]> wrote:
> in message <[email protected]>, Mark
>
>
>
> ('[email protected]') wrote:
> > On 4 Aug, 20:46, Mark
> > <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
> > wrote:
> >> > I've tried to test how strong the stem/steerer join is by gripping the
> >> > handlebars when the bike's stationary and putting pressure on the join
> >> > (more pressure than I would imagine in normal use), and it all seems
> >> > strong.
>
> >> Is it just the top of the steerer that's damaged? If so I can't see
> >> that causing a problem
> >> further down the steerer. I'm just some bloke on Usenet thobut, and I
> >> won't be riding it at 30+mph
>
> >> > It's an awkward one - a new pair of forks is about £230, which I'd
> >> > much rather not spend... but I don't want to have my bars break off at
> >> > 30mph either
>
> >> They'd look pretty mounted on a wall or, if it's a 1" steerer, I'll give
> >> you a tenner for 'em - I'm riding on an 11 year old carbon frame and my
> >> friends think it's only a matter of time before the entire thing
> >> disintegrates beneath me - a dodgy fork won't worsen the odds too much
> >> :-/
>
> > Ha ha guess you've gotta have a good sense of humour to be riding a
> > 11 year old carbon frame
>
> Why? Would you have a problem flying on an eleven year old carbon fibre
> aeroplane? If so, you'd better not fly; all modern airliners use
> significant elements of carbon fibre in their structure. If not, why do
> you think structural failure on a pushbike is more serious than structural
> failure on an aeroplane?
>
> --
> [email protected] (Simon Brooke)http://www.jasmine.org.uk/~simon/
>
> ;; If you're doing this for fun, do what seems fun. If you're
> ;; doing it for money, stop now.
> ;; Rainer Deyke

Oh, i don't have a clue actually. remember I'm the bloke that may just
have screwed up his £230 forks... and my frame is Titanium made by
Omega - would be pleasantly suprised if i was still able to ride it in
11 years - although by that point, they'll probably be back in
business again, so I can take advantage of my lifetime guarantee when
it falls apart on me.

Oh, and yes I have serious problems flying in any planes, but that's
another story.

 

[Arthur Clune]

Mark wrote:
>
> So, now, when I take the stem off and look at the top of the steerer,
> I can see that I've sort of dented and slightly squashed the top of
> the steerer.

See if you can sell the fork s/h to someone who will be able to
cut it down to below the damage (which will be safe to use),
then buy a new fork and chalk it up to experience.

If you've squashed the steerer then the stem isn't going to
grip like it's designed to. This will a) make for a weaker
coupling and b) make the stress uneven. Both of these are
bad things.

Of course, it's you that has to ride the bike, but please
don't crash in front of me!

Arthur

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
The struggle of people against power is the struggle
of memory against forgetting - Milan Kundera

 

[Roger Merriman]

Mark
<pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
wrote:

> > i don't think that carbon gets fractued like alu does so it shouldn't
> > degrade in that way though it doesn't like impacts nor sun i'd guess.
>
> I forgot to mention the crash damage...

mind you any frame if you'd attaully damadged it then it's probably
worth bining the frame.

roger
--
www.rogermerriman.com

 

[Rob Morley]

In article <[email protected]>, Arthur Clune
[email protected] says...

> If you've squashed the steerer then the stem isn't going to
> grip like it's designed to.

I don't see why it would cause a problem as long as the bung is in the
right place - the steerer should squash back into the right shape when
tightened, and I imagine the critical part is just below the stem rather
than inside it (the bit just above the crown is probably the most
stressed area, but I imagine that will have extra layers of carbon - if
it doesn't then the top end is probably well over-specced anyway).