All-Carbon Fork 1" steerer strong enuff?

I'm thinking of replacing my carbon fork with steel steerer (over 700 grams)
with an all-carbon fork (less than 400 grams). It's 1" threadless in a 16 cm
head tube. The bike is a Univega steel frame.

I'm 170# and a strong rider (for a 58 yr old).

Thanks.

John

I can only speak for the one inch "Star Carbon" made by Colnogo. It
weighs a little over 400 grams and it has a real solid feel. I think
the weakness in carbon forks would not be in the steerer but in the
stanchions. A hard whack to the sides could crack them. In a head-on
collision I also think the stanchion would break before the steerer.
If you never crash your all carbon fork it should last a very long
time.

My $0.02

Read this:

http://www.habcycles.com/techstuf.html#oneinch

At your weight, you should be fine. Take a look at True Temper Alpha Q
Sub3 or the soon to be release Two7 forks.

John Crankshaw wrote:
I'm thinking of replacing my carbon fork with steel steerer (over 700
grams)
with an all-carbon fork (less than 400 grams). It's 1" threadless in
a 16 cm
head tube. The bike is a Univega steel frame.

I'm 170# and a strong rider (for a 58 yr old).

I have an all carbon fork, steerer and blades, in a 58cm frame. 1"
steerer. Its a Performance Axiom model. I'm around 195 pounds. I
have a 2 cm spacer between the headset and stem. It all seems to work
just fine.

About the only minor complaint is keeping the headset tight. The stem
is 1.125" and uses the aluminum adapter sleeve to clamp onto the 1"
steerer. And of course the stem clamp keeps the headset tight. On my
bike the headset loosens up over time. I think it is due to the
adapter sleeve used to get the stem to fit the 1" steerer. I just
don't think it clamps tight enough to stay tight for very long. An
official 1" stem might clamp better. But with a carbon steerer I
probably would not put too much excessive force onto the stem clamp.

wrote:
John Crankshaw wrote:
I'm thinking of replacing my carbon fork with steel steerer (over
700 grams) with an all-carbon fork (less than 400 grams). It's 1"
threadless in a 16 cm head tube. The bike is a Univega steel frame.

I'm 170# and a strong rider (for a 58 yr old).

I have an all carbon fork, steerer and blades, in a 58cm frame. 1"
steerer. Its a Performance Axiom model. I'm around 195 pounds. I
have a 2 cm spacer between the headset and stem. It all seems to work
just fine.

About the only minor complaint is keeping the headset tight. The stem
is 1.125" and uses the aluminum adapter sleeve to clamp onto the 1"
steerer. And of course the stem clamp keeps the headset tight. On my
bike the headset loosens up over time. I think it is due to the
adapter sleeve used to get the stem to fit the 1" steerer. I just
don't think it clamps tight enough to stay tight for very long. An
official 1" stem might clamp better. But with a carbon steerer I
probably would not put too much excessive force onto the stem clamp.

If your top cap covers the top lip of the sleeve, then you should have no
problem. If the top cap doesn't cover the top lip of the sleeve, then you
should get a 1mm or 3mm headset spacer, put it on top of the stem, and then
the top cap on top of that. That should keep it tight.

--
Phil, Squid-in-Training

Phil, Squid-in-Training wrote:
wrote:
John Crankshaw wrote:
I'm thinking of replacing my carbon fork with steel steerer (over
700 grams) with an all-carbon fork (less than 400 grams). It's 1"
threadless in a 16 cm head tube. The bike is a Univega steel frame.

I'm 170# and a strong rider (for a 58 yr old).

I have an all carbon fork, steerer and blades, in a 58cm frame. 1"
steerer. Its a Performance Axiom model. I'm around 195 pounds. I
have a 2 cm spacer between the headset and stem. It all seems to
work just fine.

About the only minor complaint is keeping the headset tight. The
stem is 1.125" and uses the aluminum adapter sleeve to clamp onto
the 1" steerer. And of course the stem clamp keeps the headset
tight. On my bike the headset loosens up over time. I think it is
due to the adapter sleeve used to get the stem to fit the 1"
steerer. I just don't think it clamps tight enough to stay tight
for very long. An official 1" stem might clamp better. But with a
carbon steerer I probably would not put too much excessive force
onto the stem clamp.

If your top cap covers the top lip of the sleeve, then you should
have no problem. If the top cap doesn't cover the top lip of the
sleeve, then you should get a 1mm or 3mm headset spacer, put it on
top of the stem, and then the top cap on top of that. That should
keep it tight.

Also check to see that your expansion plug isn't slipping.
--
Phil, Squid-in-Training

Just make sure that the stem you use is appropriate for a
carbon-steerer model, since many 1-inch stems are not. I would also
think twice about using a 1-1/8th stem with a shim.

Years ago I upgraded to a 1-inch all carbon fork, but continued to use
my Cinelli Alter stem. I very quickly got a stress riser and ruined
the fork

Learn from my expensive mistake!

Also check to see that your expansion plug isn't slipping.

There is plenty of space above the fork steerer so the top cap is
bearing down on the spacers when tightening it. No problem getting the
headset initially tight/properly adjusted.

The expansion plug has absolutely nothing to do with keeping the
headset tight. The expansion plug, star nut, top cap, is only used to
initially adjust the headset. The stem clamps the headset into place.
Once the stem is tightened on the steerer, you can take the top cap and
expansion plug and star nut out and the headset adjustment will not
change. To test this, adjust the headset to loose or tight or correct,
makes no difference. Tighten the stem clamp. Then tighten or loosen
the top cap, expansion plug, star nut. The stem clamp on the fork
steerer will not move and the headset will not change adjustment.
Another test is to adjust the headset using the top cap, plug, star nut
but not tighten the stem on the steerer. Then ride and see if the
headset stays adjusted when the only thing keeping it tight is the top
cap. An obvious problem to this test is being able to steer if the
stem is not tightened onto the steerer but I think you could get around
this temporarily if you rode only straight and in a safe place like a
golf course.

My headset problem is due to the stem clamping onto the aluminum
adapter sleeve that presses onto the fork steerer. The clamping force
of the stem is dissipated too much when clamping onto the adapter which
circles the smooth, slick carbon steerer tube. Over time and use, the
stem and adapter slide up just a little bit and the headset becomes
loose.

wrote:
The expansion plug, star nut, top cap, is only used to
initially adjust the headset.

I thought that the expansion plug unlike a star nut is also there to
help resist compression forces when you tighten the stem around the
steerer? I've also seen really elongated top caps that extend several
centimeters down into the steerer (Cannondales come with a cap like
this), which I assume are intended to do the same?

wrote:
Also check to see that your expansion plug isn't slipping.

There is plenty of space above the fork steerer so the top cap is
bearing down on the spacers when tightening it. No problem getting
the headset initially tight/properly adjusted.

The expansion plug has absolutely nothing to do with keeping the
headset tight.

While this is true, a slipping expansion plug is still important.

If a stem is tightened and clamped with the headset properly adjusted, all
is well. If the expansion plug is slipping more than just a bit, however,
once the clamp is loosened, you'll never get it back to the correct preload.
As I write this, I notice that this doesn't follow your situation, but we
had a fellow rider whose internal aluminum sleeve was slipping out of the
steerer, with deteriorating epoxy attached, which has the same effect as a
slipping expansion plug.

My headset problem is due to the stem clamping onto the aluminum
adapter sleeve that presses onto the fork steerer. The clamping force
of the stem is dissipated too much when clamping onto the adapter
which circles the smooth, slick carbon steerer tube. Over time and
use, the stem and adapter slide up just a little bit and the headset
becomes loose.

The stem and adapter shouldn't slide up at all if the top cap is properly
preloaded and not loosening, unless you're removing the top cap and bolt
after preload. Anti-seize on the threads might help... not sure if there
are any problems with doing this.

--
Phil, Squid-in-Training