On Tuesday, May 9, 2017 at 8:19:22 PM UTC-7, John B. wrote:
On Tue, 09 May 2017 11:01:57 -0700, Joerg
wrote:

On 2017-05-09 06:23, wrote:
On Tuesday, May 9, 2017 at 1:06:01 AM UTC-7, John B. wrote:
On Mon, 8 May 2017 19:27:20 -0700 (PDT), Sir Ridesalot
wrote:

On Monday, May 8, 2017 at 10:10:59 PM UTC-4,
wrote:
On Mon, 08 May 2017 11:52:58 -0700, Joerg
wrote:

On 2017-05-08 10:55, Sir Ridesalot wrote:

[...]

At some point in time either you or a shop did something
that knackered your top nut on your 600EX headset.


I am not the only one who has that problem. Except the others
eventually didn't have the bikes anymore, which "fixed" it
for them. I keep technical things for a long time.

Anyhow, the hose clamp fixes it for me. When I get around to
it I'll put in a new non-600 headset.

I wonder if someone over tightened Joerg's 600EX headset top nut
and stripped it? Or if he has the right top nut on it? ANyhow,
lots of them were sold and lots of them were used without Joerg's
problem showing up. Joerg seems to think that he's the ONLY ONE
who rides a road bike on trails.

Cheers

Actually I have had the same problem that Joerg has. Adjust and
tighten the steering bearings and in a few days the bearings would
be loose.

A little investigation showed that the top nut instead of
bottoming out on the upper bearing race and locking it, it was
bottoming out on a very slightly too long steerer tube. I added a
washer, perhaps 3/32" thick so the top nut actually tightened
against the bearing race and have had no more problems in the last
couple of years :-)

-- Cheers,

John B.

I'll bet that this is what Joerg's problem is. It's almost impossible
to tell a steering tube that's fractionally too long. Like yours it
will appear to tighten up because it will bend just enough to appear
to be tight. Then the extra pressure will cause it to loosen up.

Got that Joerg? Try a small washer and see if that doesn't solve your
problem.


I took it apart to make sure there wasn't any other gremlin causing this
and everything was alright. The lock nut does push down as it's supposed
to do but that just isn't good enough for rides that include dirt paths
or dirt roads. Which is almost inevitable where I live.

As I wrote I was not the only one. Back in the 80's many of the more
serious riders had Shimano 600 or 600EX. I lived in the Netherlands but
close to Germany and Belgium. The riders who only did fitness rounds in
Zuid Limburg (Dutch side) didn't have problems with the headset.
Belgians and riders like me who ventured out into Belgium had them come
loose a lot. Regardless of whether they had Gazelle, Merckx or other
frames. The roads over there were often in bad shape, especially in the
Wallonie (French-speaking area). Those guys also broke spokes as often
as I do.

Full confession: I often rode in Belgium because I loved their pubs and
the Abbey Ales. Still do. That's why I have a Belgian Tripel carbonating
right now and another set of ingredients ready to brew.

I'm still wondering about the force generated. Assuming that you are
riding "in the bush" and you hit a giant rock. The resulting force is
up, trying to move the wheel and fork upward against the weight of the
bloated beer drink rider. The force generated is up, against the lower
bearing, no force what so ever on the upper race and lock nut. Then
after one rebounds from the rock and the bike falls back to earth,
with a resounding crash, the force is still taken by the bottom
bearing resisting the mass of the bike and rider. Still no force at
all against the upper bearing and lock nut.

So what is causing the upper race and lock nut to loosen? Too much
beer while working on the bike? Black Magic?

A headset can loosen due to vibration, but that typically means the lock nut is not tight enough. One could use a more robust threaded headset or a Gorilla Headlock or something like it. The hose-clamp thing is just too trailer park.

Joerg could fix all of his headset problems with a properly adjusted $20 headset -- but what fun would that be? It's far more fun to beat it with a rock in the middle of nowhere when it falls apart.

-- Jay Beattie.