[censored]'s Broken? Steerer

Tom Kunich said:

http://www.cyclingnews.com/photos/2005/oct05/suntour05/index.php?id=suntour055/IMG_0757b

Look at this - it looks like the steerer in intact and the top cap of
the expander is still attached.

it looks like the steerer broke just below where the stem is clamped to
it.

Quoted message said:

I wonder if that fork was too short and they put one of those extension
devices on it which was too loose?

i don't know what you're talking about. i didn't know they made
extensions for threadless steerers that are too short. sounds like a
dicey solution.

It isn't broken - if you look carefully you can see that the expander
is sticking out of the bottom of that stem and you can't see anything
that looks like a jagged tear or break in the steerer on the fork.

If you have a metal steerer you put in that spring steel expander. You
then put the stem on, the TOP CAP and the tension screw. You tension
the fork against the headset, tighten the stem pinch bolts and then
slightly loosen the tension bolt so that you don't have the star nut
being pulled out by the thermal expansion of the fork being different
than from the tension bolt.

If you have a carbon steerer, you leave the tension bolt tight since if
you loosen it the EXPANDER can collapse a little. This normally doesn't
matter much since the fork is held by the stem pinch bolts.

But it just so happens that some stems and some top caps don't fit
together quite correectly. Instead of the top cap sitting on top of the
stem some of them drop into the stem slightly. Then when you tighten
the stem pinch bolts they tighten on the top cap instead of the
steerer.

Now if you loosen the tension screw and give it enough time the
expander will loosen up and pull out.

Our friend Shinichi was riding along in the pack. That may look nice
and calm but the amount of juice it takes to stay in a pro peloton is
pretty high. To move around in the pack Shinichi needed to put a lot of
power into the pedals now and again.

As he was putting in a good push he was also pulling on the bars.
Eventually the bars came loose because they weren't tightened onto the
steerer.

And you can plainly see why they weren't - the expander is sticking out
of the bars and stem showing that the top cap is still locked into the
stem. If it was properly fitted it would have been lost in the crash.

All of this could have been prevented if the mechanics placed as much
value on his bike maintenance as they did on the team leader's.

Like I misspelled - the mechanic responsible for that accident deserved
a swift kick.

And the carbon steerer didn't break.