indexed steering

Francesco Devittori <frenkatfrenkdtcm> wrote in news:40c78cf6$1
@epflnews.epfl.ch:

Quoted message said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

Your headset is starting to wear out. Best to replace it
now, else it could sieze or wobble.

On Thu, 10 Jun 2004 00:19:33 +0200, Francesco Devittori

frenkatfrenkdtcm may have said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

Try cleaning and relubing. It may be nothing more than
congealed grease.

I doubt that you would see any difference in riding with a
new headset. Would you even be aware of the condition solely
on the basis of the bike's performance while riding?

--
My email address is antispammed; pull WEEDS if replying via
e-mail. Typoes are not a bug, they're a feature. Words
processed in a facility that contains nuts.

Francesco Devittori said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

There is no danger nor advantage to fixing it except that
most people are annoyed and have a poorer feel for the road
while braking with an indexed head bearing. The problem is
that it chatters while applying the brakes lightly and at
the beginning of every brake application. It also rattles
when riding over rough surfaces sounding like it will fail
any moment.

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

The other problem is that adjusting the head bearing
clearance so that it does not chatter will bake it bind when
not in the straight ahead position. There is no clean way
around this except to install a new bearing. With Shimano
headsets, this is a cartridge replacement that seldom wears
out because it is a bearing in which rotation and tilt are
separated. It is tilt that damages the bearing.

draco.acs.uci.edu8f.13.htmlOpen ↗

Jobst Brandt [email hidden]

Francesco Devittori said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

There is no danger nor advantage to fixing it except that
most people are annoyed and have a poorer feel for the road
while braking with an indexed head bearing. The problem is
that it chatters while applying the brakes lightly and at
the beginning of every brake application. It also rattles
when riding over rough surfaces sounding like it will fail
any moment.

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

The other problem is that adjusting the head bearing
clearance so that it does not chatter will make it bind when
not in the straight ahead position. There is no clean way
around this except to install a new bearing. With Shimano
headsets, this is a cartridge replacement that seldom wears
out because it is a bearing in which rotation and tilt are
separated. It is tilt that damages the bearing.

draco.acs.uci.edu8f.13.htmlOpen ↗

Jobst Brandt [email hidden]

how are they separated?

Quoted message said:

Francesco Devittori said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

There is no danger nor advantage to fixing it except that
most people are annoyed and have a poorer feel for the
road while braking with an indexed head bearing. The
problem is that it chatters while applying the brakes
lightly and at the beginning of every brake application.
It also rattles when riding over rough surfaces sounding
like it will fail any moment.

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

The other problem is that adjusting the head bearing
clearance so that it does not chatter will bake it bind
when not in the straight ahead position. There is no clean
way around this except to install a new bearing. With
Shimano headsets, this is a cartridge replacement that
seldom wears out because it is a bearing in which rotation
and tilt are separated. It is tilt that damages the
bearing.

draco.acs.uci.edu8f.13.htmlOpen ↗

Jobst Brandt [email hidden]

Jobst Brandt said:

most people are annoyed and have a poorer feel for the
road while braking with an indexed head bearing.

An indexed head bearing makes steering no-handed more
difficult. That's the main reason for me to replace it. I
replaced mine with an Ultegra cartridge style bearing last
year, which made the handling much better. It's a nice
design, and when the bearing finally wears out, just drop in
a new one. Much easier than banging out the cups.
--
terry morse Palo Alto, CA bike.terrymorse.combike.terrymorse.comOpen ↗

it's not much of an issue if you don't notice it while
riding, but from now on, it will accelerate rapidly. new
headset is the solution.

Francesco Devittori said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

Thanks

Francesco

Quoted message said:

Quoted message said:

Francesco Devittori said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any
danger riding with a headset like this? Will I notice
some benefit with a new headset?

Quoted message said:

Quoted message said:

There is no danger nor advantage to fixing it except that
most people are annoyed and have a poorer feel for the
road while braking with an indexed head bearing. The
problem is that it chatters while applying the brakes
lightly and at the beginning of every brake application.
It also rattles when riding over rough surfaces sounding
like it will fail any moment.

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

The other problem is that adjusting the head bearing
clearance so that it does not chatter will bake it bind
when not in the straight ahead position. There is no
clean way around this except to install a new bearing.
With Shimano headsets, this is a cartridge replacement
that seldom wears out because it is a bearing in which
rotation and tilt are separated. It is tilt that damages
the bearing.
draco.acs.uci.edu8f.13.htmlOpen ↗

jim beam said:

how are they separated?

Like a few simpler designs in decades past, the entire
cartridge can float within its seat.

--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

It's easier to walk holding the seat on a sidewalk. On the
other hand, riding no-handed becomes more and more difficult
the more indexed it gets. You have to deliberately wobble
eventually to keep it from stopping in the index, to ride
no-handed. Otherwise I haven't noticed that it matters.

Rotating the indexing to some other position fixes it.
--
Ron Hardin [email hidden]

On the internet, nobody knows you're a jerk.

jim beam said:

it's not much of an issue if you don't notice it while
riding, but from now on, it will accelerate rapidly. new
headset is the solution.

So if I can get my bike almost worn out, will it accelerate
rapidly too?

Mark Hickey Habanero Cycles habcycles.comhabcycles.comOpen ↗ Home of
the $695 ti frame

A Muzi said:

Quoted message said:

Quoted message said:

Francesco Devittori writes:

> My Dura-Ace 740x 1-inch threaded headset shows the
> symptoms of indexed steering. However I can only notice
> the problem when I'm not on the bike. Is there any
> danger riding with a headset like this? Will I notice
> some benefit with a new headset?

Quoted message said:

Quoted message said:

There is no danger nor advantage to fixing it except
that most people are annoyed and have a poorer feel for
the road while braking with an indexed head bearing. The
problem is that it chatters while applying the brakes
lightly and at the beginning of every brake application.
It also rattles when riding over rough surfaces sounding
like it will fail any moment.

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

The other problem is that adjusting the head bearing
clearance so that it does not chatter will bake it bind
when not in the straight ahead position. There is no
clean way around this except to install a new bearing.
With Shimano headsets, this is a cartridge replacement
that seldom wears out because it is a bearing in which
rotation and tilt are separated. It is tilt that damages
the bearing.
draco.acs.uci.edu8f.13.htmlOpen ↗

jim beam said:

how are they separated?

Like a few simpler designs in decades past, the entire
cartridge can float within its seat.

how? my cartridge ultegra has shamfered edges on the
cartridge exterior that are wedged up against the shamfered
edges of the housing under load. if they did float, you'd
feel it like any loose bearing.

the cartridge itself simply contains a single row of bearing
balls with angular races just like a "normal" headset.

Old Crow/Wild Turkey snipes:

Quoted message said:

Quoted message said:

Quoted message said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any
danger riding with a headset like this? Will I notice
some benefit with a new headset?

Quoted message said:

Quoted message said:

There is no danger nor advantage to fixing it except that
most people are annoyed and have a poorer feel for the
road while braking with an indexed head bearing. The
problem is that it chatters while applying the brakes
lightly and at the beginning of every brake application.
It also rattles when riding over rough surfaces sounding
like it will fail any moment.

Quoted message said:

Quoted message said:

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

Quoted message said:

Quoted message said:

The other problem is that adjusting the head bearing
clearance so that it does not chatter will bake it bind
when not in the straight ahead position. There is no
clean way around this except to install a new bearing.
With Shimano headsets, this is a cartridge replacement
that seldom wears out because it is a bearing in which
rotation and tilt are separated. It is tilt that damages
the bearing.

draco.acs.uci.edu8f.13.htmlOpen ↗

Quoted message said:

how are they separated?

again:

draco.acs.uci.edu8f.13.htmlOpen ↗

Jobst Brandt [email hidden]

Old Crow/Wild Turkey snipes:

Quoted message said:

Quoted message said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

Quoted message said:

It's not much of an issue if you don't notice it while
riding, but from now on, it will accelerate rapidly. New
headset is the solution.

Not true. Because this wear is caused by fretting and
because a rattling bearing has less tendency to fret, its
bearing balls lifting off intermittently and replenishing
oil in the contact area, wear is reduced. Coasting on long
descents is what causes bearing races to develop dimples.

Jobst Brandt [email hidden]

Terry Morse said:

Quoted message said:

most people are annoyed and have a poorer feel for the
road while braking with an indexed head bearing.

Quoted message said:

An indexed head bearing makes steering no-handed more
difficult. That's the main reason for me to replace it. I
replaced mine with an Ultegra cartridge style bearing last
year, which made the handling much better. It's a nice
design, and when the bearing finally wears out, just drop
in a new one. Much easier than banging out the cups.

That is true only if the head bearing is adjusted for no
clearance in the straight ahead position. Then the bearing
will home from binding. Indexing in the rattling state
exerts so little restoration torque that it has no
perceptible effect on no-hands riding. In fact, the term
indexing doesn't apply unless the bearing is adjusted to
remove straight ahead clearance because otherwise there is
practically no homing tendency. However, riding no-hands can
cause the bearing to chatter most conspicuously.

Jobst Brandt [email hidden]

Ron Hardin said:

It's easier to walk holding the seat on a sidewalk. On the
other hand, riding no-handed becomes more and more
difficult the more indexed it gets. You have to
deliberately wobble eventually to keep it from stopping in
the index, to ride no-handed. Otherwise I haven't noticed
that it matters.

As I mentioned, this is not a problem until the bearing is
adjusted for wear.

Quoted message said:

Rotating the indexing to some other position fixes it.

This requires rotating one of the races (not the ball cage)
by a half ball space. Dimples occur on the upper bearing as
well as the lower one but far slower.

Jobst Brandt [email hidden]

Quoted message said:

Old Crow/Wild Turkey snipes:

Quoted message said:

Quoted message said:

My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

Quoted message said:

It's not much of an issue if you don't notice it while
riding, but from now on, it will accelerate rapidly. New
headset is the solution.

Not true. Because this wear is caused by fretting and
because a rattling bearing has less tendency to fret, its
bearing balls lifting off intermittently and replenishing
oil in the contact area, wear is reduced. Coasting on long
descents is what causes bearing races to develop dimples.

it's not fretting. we've already established that.

google.comgroupsOpen ↗
newssvr25.news.prodigy.com&output=gplain

and it was independently verified by carl fogel.

once the bearings have brinelled, increased play allows the
bearing elements to accelerate more before impact, thereby
adding to brinelling damage.

Quoted message said:

Old Crow/Wild Turkey snipes:

Quoted message said:

Quoted message said:

>My Dura-Ace 740x 1-inch threaded headset shows the
>symptoms of indexed steering. However I can only notice
>the problem when I'm not on the bike. Is there any
>danger riding with a headset like this? Will I notice
>some benefit with a new headset?

Quoted message said:

Quoted message said:

There is no danger nor advantage to fixing it except that
most people are annoyed and have a poorer feel for the
road while braking with an indexed head bearing. The
problem is that it chatters while applying the brakes
lightly and at the beginning of every brake application.
It also rattles when riding over rough surfaces sounding
like it will fail any moment.

Quoted message said:

Quoted message said:

This does not cause shimmy or other instabilities as is
often mentioned. Shimmy is an elastic resonance of the
bicycle. Free play in bearings interferes with that.

Quoted message said:

Quoted message said:

The other problem is that adjusting the head bearing
clearance so that it does not chatter will bake it bind
when not in the straight ahead position. There is no
clean way around this except to install a new bearing.
With Shimano headsets, this is a cartridge replacement
that seldom wears out because it is a bearing in which
rotation and tilt are separated. It is tilt that damages
the bearing.

draco.acs.uci.edu8f.13.htmlOpen ↗

Quoted message said:

how are they separated?

again:

draco.acs.uci.edu8f.13.htmlOpen ↗

er, by saying that "The Shimano bearings have races that are
sufficiently reentrant that the races snap permanently
together." you're trying to say they somehow don't have
angular load surfaces just like any other headset??? that
would be interesting!

Old Crow/Wild Turkey said:

Quoted message said:

Like a few simpler designs in decades past, the entire
cartridge can float within its seat.

Quoted message said:

How? My cartridge ultegra has shamfered edges on the
cartridge exterior that are wedged up against the
shamfered edges of the housing under load. If they did
float, you'd feel it like any loose bearing.

Quoted message said:

The cartridge itself simply contains a single row of
bearing balls with angular races just like a "normal"
headset.

It takes a special cartridge bearing to swivel on a
spherical seat.

Subject: 8f.13 Indexed Steering From: Jobst Brandt
<[email hidden]> Date: Wed, 10 Jun 2004
10:08:29 PDT

Quoted message said:

In the several years I spent working in a pro shop, I have
never seen a case of "index steering" (yes, we called it
that) that was _not_ caused by a "brinelled" headset - one
with divots in the races. I am 99.999 percent certain that
that is your problem. What are you going to do if you
don't fix it? I suggest that you fix the headset even if
you sell the bike, as a damaged headset could be grounds
for a lawsuit if the buyer crashes.

I disagree on two points. First, because you use the term
"Brinell" that conveys a notion as incorrect as the phrase
"my chain stretched from climbing steep hills" and second,
because there is no possibility of injury or damage from
"indexed" steering head bearings. The effect is mostly
perception of failure from the rattling noise and clunky
feel while braking lightly. It has such a small effect that
it is imperceptible when riding no-hands unless the bearing
clearance has been adjusted in the straight ahead position.
Then the bearing will bind off center.

Damage to head bearings seems to be twofold in this case
because properly adjusted steering can only become looser
from dimples, dimples that cannot immobilize steering.
Therefore, the head adjustment was too tight. However,
dimpling is not caused by impact, but rather by lubrication
failure that occurs while riding straight ahead, giving the
steering a preferred home position. This occurs more easily
with a correctly adjusted bearing than with a loose one that
rattles and clunks. Rattling replenishes lubricant between
balls and races, something that would otherwise not not
occur. Off road bicycles suffer less from this malady than
road bicycles because it occurs primarily during long
straight descents that on which no steering motions, that
might replenish lubricant, are made.

If you believe it comes from hammering the balls into the
races, you might try to cause some dimples by hammering on
the underside of the fork crown of a clunker bike of your
choice. Those who hammered cotters on steel cranks will
recall no dimples on the spindle, even though it has a far
smaller diameter than the head bearing and the blows were
more severe and direct, supported by no more than one or
two balls.

Bearing balls make metal-to-metal contact only under
fretting loads (microscopic oscillations) while the races
are is not rotating. Any perceptible steering motion will
replenish lubricant from the oily meniscus surrounding each
ball contact patch. Peering over the bars at the front hub
while coasting down a road at 20+ mph you will notice the
fork ends vibrating fore and aft. This motion does not arise
at the fork end, but at the fork crown, where it bends the
steer tube. Both head bearings rotate in fretting motion
crosswise to the normal plane of rotation as the steer tube
bends. Dimples form in the forward and rearward quadrant of
both upper and lower bearings from this fretting. That they
also form in the upper bearing shows they are not directly
load related.

Lubrication failure from fretting causes metal to metal
contact that forms microscopic welds between balls and
races. These welds repeatedly tear material from the softer
of the two causing elliptical milky dimples in both races.
Were these Brinelling marks (embossed through force), they
would be shiny and smooth and primarily on the inner race of
the bearing. Various testimonials for the durability of one
bearing over another are more likely an indication of
lubrication than the design of the bearing. Ball bearings
with separate cups and cones have been used as head bearings
longer than they should considering their poor performance.

The question has been raised whether steering to either side
would reveal a second preferred position in which the balls
fall into matching dimples. Since bearing balls move at
roughly half the rate of steering motion, with 20 balls,
this requires a steering angle of 36 degrees for dimples in
both races to match again with the balls. However, the balls
do not arrive exactly at the spot where dimples are again
opposite because they move at a ratio of (od-bd)/(id+bd) od:
outer race diameter, id: inner race diameter, bd: ball
diameter. This ratio not being 1:1, the balls do not
naturally arrive at the second coincidence of the race
dimples although they usually drop in.

Roller bearings of various designs have been tried, and it
appears that they were possibly the ones that finally made
obvious that fore and aft motion was the culprit all along;
a motion that roller bearings were less capable of absorbing
than balls. This recognition lead to using spherical
alignment seats under the rollers. Although this stopped
dimpling, these bearings worked poorly because the needle
complement tended to shift off center, skewing the needles
and causing large bearing friction as the rollers skate.

Shimano, Chris King, Cane Creek and others, offer angular
contact, full ball complement, spherically aligned cartridge
bearings. The Shimano cartridge bearings have contact seals,
not exposed to weather, to retain grease for life of the
bearing. The races are sufficiently reentrant that they snap
permanently together with sufficient preload to prevent
rocking (fretting) motion perpendicular to the rotational
axis. Spherical steel rings, that move as plain bearings
against an aluminum housing, support the cartridge bearing
to absorb, otherwise damaging, out-of-plane motion while the
cartridge bearing does the steering.

-------------------------
Jobst Brandt [email hidden]

Quoted post said:

Originally posted by Francesco Devit
My Dura-Ace 740x 1-inch threaded headset shows the
symptoms of indexed steering. However I can only notice
the problem when I'm not on the bike. Is there any danger
riding with a headset like this? Will I notice some
benefit with a new headset?

Thanks

Francesco

Is this a mid 80's vintage headset with the titanium races? I've got the same and it too has indexed. I wonder if this was a common problem with this particular headset. My stronglight A9 which is older than the durace headset doesn't have this problem.