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.

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?

I posted a similar query a couple of months ago and received a number of
useful responses. Do a Google Groups search; the thread was entitled
"Handlebars do not rotate smoothly".

I also see quite a few past threads about this issue.

HTH

Reid

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.

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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.

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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.

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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 http://bike.terrymorse.com/

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.
http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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
http://www.habcycles.com
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.
http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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.

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

Quoted message said:

how are they separated?

again:

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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]

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]

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.

http://www.google.com/groups?selm=hM9Bb.68029%24Jn.49626%40newssvr25.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.

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

Quoted message said:

how are they separated?

again:

http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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]