all carbobn fork & stem question

William Evans said:

Hello,
I recently purchased an all carbon fork with a 1" steerer. I'm now looking
for a threadless stem. Most stems available are for 1 1/8 steerer tubes,
but come with a 1" shim. Are there any issues with using a shim with a
carbon fork?

thanks for any help,
wre

Not at all, what all of the stems of today use. Issue is the amount of
spacers under the stem. For 1 inch, a good ROT is 1 inch or
25mm....maximum.

"William Evans" wrote

Quoted message said:

I recently purchased an all carbon fork with a 1" steerer. I'm now

looking

Quoted message said:

for a threadless stem. Most stems available are for 1 1/8 steerer tubes,
but come with a 1" shim. Are there any issues with using a shim with a
carbon fork?

Have the same setup on one my circa 1998 road bike, using a 1 1/8" Ritchey
New Pro stem. One thing I noticed with the shim is that the edges at the
slot were very sharp, unlike the edges of the slot in the stem itself. I
rounded off these edges with some sandpaper to avoid gouging the steerer
upon tightening up the pinch bolts.

Brian Ray

I second the warning about burrs around the slot.

Also, make sure the shim runs the entire vertical length of the stem's
steerer clamp. Usually, the included shim is shorter, so the contact
area is much smaller, and there will be a gap between the top of the
spacers and the bottom of the shim (or between the top cap and the top
of the shim). This will create stress risers.

Bottom line, be careful and if you aren't sure about anything, have
somebody take a look at it before you tighten everything down. 1-inch
carbon steerers are fragile. I ruined a brand new (and expensive) Look
HSC years ago by installing a Cinelli Alter stem, which I later found
out had a clamp that wasn't carbon friendly.

Dave said:

I second the warning about burrs around the slot.

Also, make sure the shim runs the entire vertical length of the stem's
steerer clamp. Usually, the included shim is shorter, so the contact
area is much smaller, and there will be a gap between the top of the
spacers and the bottom of the shim (or between the top cap and the top
of the shim). This will create stress risers.

Bottom line, be careful and if you aren't sure about anything, have
somebody take a look at it before you tighten everything down. 1-inch
carbon steerers are fragile. I ruined a brand new (and expensive)
Look HSC years ago by installing a Cinelli Alter stem, which I later
found out had a clamp that wasn't carbon friendly.

With carbon steerers, I usually just barely tighten the top steerer bolt on
the stem and let the bottom one take the load. Besides, with even a
low-pressure clamping, it's more than rigid enough to stay in place unless
one crashes.

--
Phil, Squid-in-Training

Phil said:

Dave said:

I second the warning about burrs around the slot.

Also, make sure the shim runs the entire vertical length of the stem's
steerer clamp. Usually, the included shim is shorter, so the contact
area is much smaller, and there will be a gap between the top of the
spacers and the bottom of the shim (or between the top cap and the top
of the shim). This will create stress risers.

Bottom line, be careful and if you aren't sure about anything, have
somebody take a look at it before you tighten everything down. 1-inch
carbon steerers are fragile. I ruined a brand new (and expensive)
Look HSC years ago by installing a Cinelli Alter stem, which I later
found out had a clamp that wasn't carbon friendly.

With carbon steerers, I usually just barely tighten the top steerer bolt on
the stem and let the bottom one take the load. Besides, with even a
low-pressure clamping, it's more than rigid enough to stay in place unless
one crashes.

Reduce the stem clamp 'force' by 50%? This is not sound advice, IMO.
Torque both properly, use 5mm spacer on top of the stem for all carbon
steerers but don't arbitrarily loosen the top one.

Quoted message said:

--
Phil, Squid-in-Training