How tight to clamp a stem on a carbon steertube?

Hi, when tigtening the bolts that attach a stem on a road carbon steertube
(ie not the headset top cap), how tight can I go before damaging the
steertube? Or do I even have to worry about causing any damage.

On a cromo steertube, I'd say that the stem's bolts would fail or strip out
long before the steertube, but when I'm tightening a carbon one (heck even
when I'm tightening my carbon seatpost) I'm always scared I'll someday hear
an almighty CRACK!

any thoughts?

Me wrote:
Hi, when tigtening the bolts that attach a stem on a road carbon steertube
(ie not the headset top cap), how tight can I go before damaging the
steertube? Or do I even have to worry about causing any damage.

On a cromo steertube, I'd say that the stem's bolts would fail or strip out
long before the steertube, but when I'm tightening a carbon one (heck even
when I'm tightening my carbon seatpost) I'm always scared I'll someday hear
an almighty CRACK!

Whatever kind of stem or steerer you use, it should be tightened enough
that if you stand in front of the bike and grip the front wheel between
your knees, it should take a good firm twist on the handlebars to make
the stem turn on/in the steerer. If you can't turn the handlebars, it's
too tight, and it is more likely to cause injury or parts damage in the
event of a crash.

Sheldon "Tight Enough, But Not Too Tight" Brown
+-----------------------------------------------+
| I saw a man pursuing the horizon; |
| Round and round they sped. |
| I was disturbed at this; |
| I accosted the man. |
| |
| "It is futile," I said, |
| "You can never--" |
| |
| "You lie," he cried, |
| And ran on. |
| --Stephen Crane |
+-----------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

I've never heard of that before... is that just for carbon forks?

Mike
http://mikebeauchamp.com

"Sheldon Brown" wrote in message
...
Me wrote:
Hi, when tigtening the bolts that attach a stem on a road carbon
steertube
(ie not the headset top cap), how tight can I go before damaging the
steertube? Or do I even have to worry about causing any damage.

On a cromo steertube, I'd say that the stem's bolts would fail or strip
out
long before the steertube, but when I'm tightening a carbon one (heck
even
when I'm tightening my carbon seatpost) I'm always scared I'll someday
hear
an almighty CRACK!

Whatever kind of stem or steerer you use, it should be tightened enough
that if you stand in front of the bike and grip the front wheel between
your knees, it should take a good firm twist on the handlebars to make
the stem turn on/in the steerer. If you can't turn the handlebars, it's
too tight, and it is more likely to cause injury or parts damage in the
event of a crash.

Sheldon "Tight Enough, But Not Too Tight" Brown
+-----------------------------------------------+
| I saw a man pursuing the horizon; |
| Round and round they sped. |
| I was disturbed at this; |
| I accosted the man. |
| |
| "It is futile," I said, |
| "You can never--" |
| |
| "You lie," he cried, |
| And ran on. |
| --Stephen Crane |
+-----------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

I've never heard of that before... is that just for carbon forks?

Mike

You mean still loose enough that you can turn the bars to the side with your
knees keeping the fork still? Yup, thats been true for years. it should
require a reasonable amount of force, but not too uch(yeah, thats very
specific...)
that way if you crash and the bars get wrenched off center, you can
twist them back again. I was racing in West Virginia years ago, and on a long
climb I passed 2 riders(same team) that were side by side , one of whom lost
control(I never figured out how, as they weren't going very fast.)as I was
passing and hit the other, who crashed into me. having had some aggressive bump
training from a track rider friend, I managed to remain up-right, but my bars
were knocked sideways. I continued up the mountain, and twisted the bars back
when it levelled out. couldnt have done that, as I had no tools on me but a
tire.

On Wed, 03 Sep 2003 22:04:35 -0400, Sheldon Brown
wrote:
your knees, it should take a good firm twist on the handlebars to make
the stem turn on/in the steerer. If you can't turn the handlebars, it's

Wouldn't that be a destructive test for a carbon steerer?

Sheldon "Tight Enough, But Not Too Tight" Brown
--
Rick Onanian

I wrote:

your knees, it should take a good firm twist on the handlebars to make
the stem turn on/in the steerer. If you can't turn the handlebars, it's

Rick Onanian asked:

Wouldn't that be a destructive test for a carbon steerer?

Only if the stem had been overtightened already, and you were a real
gorilla.

Sheldon "Not _That_ Tight" Brown
+---------------------------------------------------+
| There was a man with a tongue of wood |
| Who essayed to sing. |
| And in truth it was lamentable. |
| But there was one who heard |
| The clip-clapper of this tongue of wood |
| And knew what the man wished to sing, |
| And with that the singer was content. |
| --Stephen Crane |
+---------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

As long as you do not point load the carbon there should be no problem. I
always leave at least 1/4" of the fork extending beyond the end of the stem.
Also, take turns tightening bolts(assuming you have more than one) to avoid
an uneven distribution of force.


"Me" wrote in message ...
Hi, when tigtening the bolts that attach a stem on a road carbon steertube
(ie not the headset top cap), how tight can I go before damaging the
steertube? Or do I even have to worry about causing any damage.

On a cromo steertube, I'd say that the stem's bolts would fail or strip
out
long before the steertube, but when I'm tightening a carbon one (heck even
when I'm tightening my carbon seatpost) I'm always scared I'll someday
hear
an almighty CRACK!

any thoughts?