Carbon Fork insert

Brendo said:

I've been having trouble with my headset coming loose. I've got a
Reynolds Ouzo pro fork with a full carbon steerer, and a Reynolds
wedge style headset. No matter how I tighten it, it works it's way
loose after a few rides. When tightening I do the following.
- Undo everything on the top side of the steerer.
- Poke the wedge down the steerer about 1 1/2 inches, and tighten the
expander bolt very tight.
- Pull fork up hard, making sure bearings are in place.
- Slide the stem down tight, making sure the top of the steerer is a
few mm below the top of the stem, and screw the cap onto the wedge.
- Straighten bars, and tighten all the bolts.
- Make sure the cap is tight.

My problem is that the cap is never SUPER tight. Each additional turn
only raises the wedge. I'm a bit concerned about crushing the steerer
if I tighten the stem too hard, as there is nothing to hold it's shape
because the wedge appears to sit just below the bottom of the stem
mount on the steering tube. Within a few rides, the forks are loose,
not majorly, but at 115kg there is a fair bit of pressure there. I
don't want to bugger up my steerer or my head tube.

I saw on the net an insert, which was an aluminium cyclinder which
slips inside the steering tube, and is bonded via an epoxy. The top of
the cyclinder has a thread inside it, and it sits flush with the
outside of the steering tube.

Has anyone used these, and if so, where did you get it from?

OR is there a better way to secure a carbon steerer?

Brendo

I don't have a carbon steerer but I would not be too worried
about the cap coming loose - once the stem is tightened, the
cap's job is done and I think (someone correct me if I'm wrong!)
you could remove it entirely. Of course, you don't want the
cap to come off while you're riding the bike. The cap is a
"back-up" once the stem has been tightened.

Two things come to mind:

Have you tried roughing up the inside surface of the steerer?
A bit of heavy sand paper will roughen the surface bit and give
the plug something to grip. I know that my LBS did this to
my seat post once it's height had been determined. You might
need to roughen the outside of the steerer where the stem clamps
as well as the inside of the stem itself.

Have you got a torque wrench and are you following the manufacturer's
recommended torque settings? Everything I've seen about carbon
components says that correct torquing is very important.

I haven't used the sleeve insertion you mention but it seems to
me that it would work fine. Only thing would be that once it's
epoxied in place, it's not coming out again....

DeF

--
e-mail: d.farrow@your finger.murdoch.edu.au
To reply, you'll have to remove your finger.

Quoted message said:

I don't have a carbon steerer but I would not be too worried
about the cap coming loose - once the stem is tightened, the
cap's job is done and I think (someone correct me if I'm wrong!)
you could remove it entirely. Of course, you don't want the
cap to come off while you're riding the bike. The cap is a
"back-up" once the stem has been tightened.

So it is a loose stem that is the problem??

Quoted message said:

Two things come to mind:

Have you tried roughing up the inside surface of the steerer?
A bit of heavy sand paper will roughen the surface bit and give
the plug something to grip. I know that my LBS did this to
my seat post once it's height had been determined. You might
need to roughen the outside of the steerer where the stem clamps
as well as the inside of the stem itself.

Have you got a torque wrench and are you following the manufacturer's
recommended torque settings? Everything I've seen about carbon
components says that correct torquing is very important.

I haven't got a torque wrench. I've been using the 'tighten till you
think really tight, but don't crush it' method

Quoted message said:

I haven't used the sleeve insertion you mention but it seems to
me that it would work fine. Only thing would be that once it's
epoxied in place, it's not coming out again....

But why would you want it out again? That is assuming you put it in
properly in the first place. 🙂

Brendo

Brendo said:

Quoted message said:

I don't have a carbon steerer but I would not be too worried
about the cap coming loose - once the stem is tightened, the
cap's job is done and I think (someone correct me if I'm wrong!)
you could remove it entirely. Of course, you don't want the
cap to come off while you're riding the bike. The cap is a
"back-up" once the stem has been tightened.

So it is a loose stem that is the problem??

Sounds like it to me. Like I almost said in my first post: the
job of the cap is to put pressure on the headset bearings until
you've tightened the stem up. Once the stem is tightened, I
think the job of the cap is largely cosmetic (again, someone
might correct me on this).

The other issue could be that it's taking a long time for a
new headset to seat into the forks and head tube. However, you
didn't mention fitting a new head set and if this were the
problem it goes away after you've tightened the cap a couple of
times.

In any case, the stem should not come loose. Doing a bit of
roughening (as mentioned below) might just do the trick.

Quoted message said:

Quoted message said:

Two things come to mind:

Have you tried roughing up the inside surface of the steerer?
A bit of heavy sand paper will roughen the surface bit and give
the plug something to grip. I know that my LBS did this to
my seat post once it's height had been determined. You might
need to roughen the outside of the steerer where the stem clamps
as well as the inside of the stem itself.

Have you got a torque wrench and are you following the manufacturer's
recommended torque settings? Everything I've seen about carbon
components says that correct torquing is very important.

I haven't got a torque wrench. I've been using the 'tighten till you
think really tight, but don't crush it' method

Well that might be fine if you're a professional mechanic with
a in-built sense of what that is. Personally, I'd get/borrow
a torque wrench then you know it's right. You can get reasonable
ones for less than $100 which (given you've got forks with a
carbon steerer) is likely much less than the last/next bit of
bling that made/makes its way into your shed!

Quoted message said:

Quoted message said:

I haven't used the sleeve insertion you mention but it seems to
me that it would work fine. Only thing would be that once it's
epoxied in place, it's not coming out again....

But why would you want it out again? That is assuming you put it in
properly in the first place. 🙂

That's fine as an assumption. The only issue is if at some stage
in the future you want to shorten the steerer. I got mine shortened
so that there was no steerer poking out the top of my stem but only
after I'd been riding for month so I was confident the bars were the
correct height.

Quoted message said:

Brendo

DeF

--
e-mail: d.farrow@your finger.murdoch.edu.au
To reply, you'll have to remove your finger.

DeF said:

I don't have a carbon steerer but I would not be too worried
about the cap coming loose - once the stem is tightened, the
cap's job is done and I think (someone correct me if I'm wrong!)
you could remove it entirely. Of course, you don't want the
cap to come off while you're riding the bike. The cap is a
"back-up" once the stem has been tightened.

You're right. The cap should be tightened first, just enough to prevent
play in the headset, then the stem bolts.

It's just occurred to me that I could shave a few grams by then
replacing the cap and spacers above the stem with a piece of duct
tape :-)

--
Home page: http://members.westnet.com.au/mvw

Brendo said:

OR is there a better way to secure a carbon steerer?

I've never had trouble with the expansion plug in my carbon
steerer, but if I did I'd try making sure that surfaces were
completely clean and devoid of oil or grease, and then
abrading the outside of the plug so that it grips the carbon
better.

Apparently there's a new gunk on the market which helps
carbon grip - it has tiny little balls of something in suspension.
You could try some of that.

As for torque, I tighten the stem bolts to just 5Nm and it stays put.
I don't see why a great deal of holding force should be needed.

--
Home page: http://members.westnet.com.au/mvw

DeF said:

Sounds like it to me. Like I almost said in my first post: the
job of the cap is to put pressure on the headset bearings until
you've tightened the stem up. Once the stem is tightened, I
think the job of the cap is largely cosmetic (again, someone
might correct me on this).

It's a good failsafe if the stem does come loose, since it should stop it
flying right off. Although steering is tricky, it's still possible, and
you've got brakes. It's a lot nicer than pulling the whole stem and bars
off just as you try to hop a pothole or kerb.

But if everything is working, it's actually possible to pull the top cap
off. I've got a bike like that ATM since I used the headlock from another
bike to install the stem.

Quoted message said:

Well that might be fine if you're a professional mechanic with a
in-built sense of what that is.

You can also get pretty close by using a bit of maths. If you're supposed
to exert 10Nm (for example), that's about 1kg at 1m. On a 10cm allen key
you need to exert the force it'd take to lift a 10l bucket full of water.
On a 5cm one it'd be a 20l bucket. In theory you could even hang a bucket
off the allen key...

--
Dave Hughes | [email hidden]
Against boredom, the Gods themselves struggle in vain.
- Nietzche

Brendo said:

I've been having trouble with my headset coming loose. I've got a
Reynolds Ouzo pro fork with a full carbon steerer, and a Reynolds
wedge style headset. No matter how I tighten it, it works it's way
loose after a few rides. When tightening I do the following.
- Undo everything on the top side of the steerer.
- Poke the wedge down the steerer about 1 1/2 inches, and tighten the
expander bolt very tight.
- Pull fork up hard, making sure bearings are in place.
- Slide the stem down tight, making sure the top of the steerer is a
few mm below the top of the stem, and screw the cap onto the wedge.
- Straighten bars, and tighten all the bolts.
- Make sure the cap is tight.

My problem is that the cap is never SUPER tight. Each additional turn
only raises the wedge. I'm a bit concerned about crushing the steerer
if I tighten the stem too hard, as there is nothing to hold it's shape
because the wedge appears to sit just below the bottom of the stem
mount on the steering tube. Within a few rides, the forks are loose,
not majorly, but at 115kg there is a fair bit of pressure there. I
don't want to bugger up my steerer or my head tube.

I saw on the net an insert, which was an aluminium cyclinder which
slips inside the steering tube, and is bonded via an epoxy. The top of
the cyclinder has a thread inside it, and it sits flush with the
outside of the steering tube.

Has anyone used these, and if so, where did you get it from?

OR is there a better way to secure a carbon steerer?

Brendo

I had this problem with a Fondriest carbon fork/steerer and it turned
out to be the steerer had broken. The bond between the aluminium part
at the bottom of the steerer and the carbon had slightly broken, new
fork was the only solution. I suggest you take it to a bike shop and
get them to put it in a vice and push on it. Does it creak when you
ride? Mine was making noises and the same noise when applying force
to it in a vice.

Quoted message said:

Brendo said:

I've been having trouble with my headset coming loose. I've got a
Reynolds Ouzo pro fork with a full carbon steerer, and a Reynolds
wedge style headset. No matter how I tighten it, it works it's way
loose after a few rides. When tightening I do the following.
- Undo everything on the top side of the steerer.
- Poke the wedge down the steerer about 1 1/2 inches, and tighten the
expander bolt very tight.
- Pull fork up hard, making sure bearings are in place.
- Slide the stem down tight, making sure the top of the steerer is a
few mm below the top of the stem, and screw the cap onto the wedge.
- Straighten bars, and tighten all the bolts.
- Make sure the cap is tight.

Quoted message said:

My problem is that the cap is never SUPER tight. Each additional turn
only raises the wedge. I'm a bit concerned about crushing the steerer
if I tighten the stem too hard, as there is nothing to hold it's shape
because the wedge appears to sit just below the bottom of the stem
mount on the steering tube. Within a few rides, the forks are loose,
not majorly, but at 115kg there is a fair bit of pressure there. I
don't want to bugger up my steerer or my head tube.

Quoted message said:

I saw on the net an insert, which was an aluminium cyclinder which
slips inside the steering tube, and is bonded via an epoxy. The top of
the cyclinder has a thread inside it, and it sits flush with the
outside of the steering tube.

Quoted message said:

Has anyone used these, and if so, where did you get it from?

Quoted message said:

OR is there a better way to secure a carbon steerer?

Quoted message said:

Brendo

I had this problem with a Fondriest carbon fork/steerer and it turned
out to be the steerer had broken. The bond between the aluminium part
at the bottom of the steerer and the carbon had slightly broken, new
fork was the only solution. I suggest you take it to a bike shop and
get them to put it in a vice and push on it. Does it creak when you
ride? Mine was making noises and the same noise when applying force
to it in a vice.

I haven't noticed any creaking when I ride, only the 'click' as the
bearings unseat and then seat again. It's only moved a mm or less, but
it's noticeable.

I'll try roughing up the outside of the steerer and seeing if the stem
grips it a bit better. More news as it happens...

brendo

Had a more detailed look. I got a new stem about 8 months back. It
appears that with the spacer fitted underneath the stem, the steerer
does not go high enough up the inside of the stem. The result is that
the top edge of the steerer sits below the top of the stem clamp, such
that it is inside the hollow where the stem and the clamp meet. (Does
this make any sense??) As such, the only gripping part is a small
(2mm) wide section at the bottom of the stem clamp.

Solution... I went to the LBS and bought a combination of spacers, and
set them up so that the top of the steerer now sits almost flush with
the top of the stem. This means the bars are now a mm or two lower,
but given that the gap between the top of the bars and the top of the
seat is already 14cm, I don't think I will notice it. Can't wait for
some cash to get a custom!!!

Also roughed up the outside of the steerer with some emery paper. Just
wanted to, gave me something to do for 10 minutes.

I think this will cure it, tomorrow will tell.

Thanks for all the advice.

Brendo

Brendo said:

Had a more detailed look. I got a new stem about 8 months back. It
appears that with the spacer fitted underneath the stem, the steerer
does not go high enough up the inside of the stem. The result is that
the top edge of the steerer sits below the top of the stem clamp, such
that it is inside the hollow where the stem and the clamp meet. (Does
this make any sense??) As such, the only gripping part is a small
(2mm) wide section at the bottom of the stem clamp.

This would definitely be a problem. The top of the steerer should
be 1 to 2 mm below the top of the stem. The top cap should push down
on the stem which pushes down through the spacers to put pressure on
the head set. For carbon steerers, I think the steerer and stem should
be flush and a thin spacer placed between the cap and the top of the
stem so that pressure can be applied to the stem. There should be some
instructions and diagrams that come with the forks.

Quoted message said:

Solution... I went to the LBS and bought a combination of spacers, and
set them up so that the top of the steerer now sits almost flush with
the top of the stem. This means the bars are now a mm or two lower,
but given that the gap between the top of the bars and the top of the
seat is already 14cm, I don't think I will notice it. Can't wait for
some cash to get a custom!!!

Also roughed up the outside of the steerer with some emery paper. Just
wanted to, gave me something to do for 10 minutes.

This should help.

Quoted message said:

I think this will cure it, tomorrow will tell.

So how did it go?

Quoted message said:

Thanks for all the advice.

Brendo

Quoted message said:

DeF

--
e-mail: d.farrow@your finger.murdoch.edu.au
To reply, you'll have to remove your finger.