indexed steering
Francesco Devittori
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
Ken
@epflnews.epfl.ch:
Your headset is starting to wear out. Best to replace it now, else it could
sieze or wobble.
Reid Priedhorsky
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
Werehatrack
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.
jobst....@stanfordalumni.org
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
jobst....@stanfordalumni.org
jobst....@stanfordalumni.org
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
jim beam
Terry Morse
> 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/
jim beam
now on, it will accelerate rapidly. new headset is the solution.
A Muzi
>>> 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?
> jobst....@stanfordalumni.org wrote:
>> 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 wrote:
> 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
Ron Hardin
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
rhha...@mindspring.com
On the internet, nobody knows you're a jerk.
Mark Hickey
>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
jim beam
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.
jobst....@stanfordalumni.org
http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html
> how are they separated?
again:
jobst....@stanfordalumni.org
>> 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.
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
jobst....@stanfordalumni.org
jobst....@stanfordalumni.org
>> 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?
> 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
jobst....@stanfordalumni.org
jobst....@stanfordalumni.org
> 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.
> 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
jobst....@stanfordalumni.org
jim beam
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.
jim beam
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!
jobst....@stanfordalumni.org
>> 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.
It takes a special cartridge bearing to swivel on a spherical seat.
Subject: 8f.13 Indexed Steering
From: Jobst Brandt <jobst....@stanfordalumni.org>
Date: Wed, 10 Jun 2004 10:08:29 PDT
> 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
jobst....@stanfordalumni.org
kgatwork
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.
--
Francesco Devittori
no, it should have seen the light in 1994, just one year or so before
the 7700. It doesn't smell titanium.
kgatwork
Thanks, I just remember reading/hearing about the old DA titanium raced
headsets being not very good (of course after I purchased and installed
it) and how the 600 ultegra was better designed back when I bought my DA
headset. But that was a long time ago.
--
jim beam
<snip>
> 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.
with respect, the only time there's ever a plain bearing effect is when
the cartridge in inserted the wrong way up. other than that, it behaves
in exactly the same way as a normal headset bearing in terms of race
allignment & ball allignment. there is absolutely /no/ relative motion
between the cartridge & the holder. the fact that there is a holder is
irrelevant - just as if the holder were the recess in which integrated
headset bearing cartridges sit.
Richard Ney
Coasting on long descents is what causes bearing races to
> develop dimples.
Does this stament include long twisty descents? Descending around here
is one corner right after the next. Doesn't that lubricate the bearing
enough to prevent fretting?
jobst....@stanfordalumni.org
>> Coasting on long descents is what causes bearing races to develop
>> dimples.
> Does this statement include long twisty descents? Descending around
> here is one corner right after the next. Doesn't that lubricate the
> bearing enough to prevent fretting?
That depends on how fast you go because steering angles are small
enough that on fast roads, no appreciable bearing ball motion occurs.
You'll notice that in the picture below, the steering angle is tiny
and ball movement is half of that. That means that during the curve
fretting can occur slightly off center and on the straight parts it
occurs on center. I don't know how many vibratory cycles it takes to
deplete the bearing interface of lubricant but I am certain it does.
As I related in this regard, tightly tethered autos shipped by rail
and truck have suffered ruined differential pinion and wheel bearings.
Cars that most commonly display the pinion bearing symptoms today are
BMW's. I hear them roll by in traffic with a distinct "SHHHHHHHHHHHH"
independent of whether they are on the gas pedal or off.
Jobst Brandt
jobst....@stanfordalumni.org
Richard Ney
>>> Coasting on long descents is what causes bearing races to develop
>>> dimples.
>
>> Does this statement include long twisty descents? Descending around
>> here is one corner right after the next. Doesn't that lubricate the
>> bearing enough to prevent fretting?
>
> That depends on how fast you go because steering angles are small
> enough that on fast roads, no appreciable bearing ball motion occurs.
> You'll notice that in the picture below, the steering angle is tiny
> and ball movement is half of that. That means that during the curve
> fretting can occur slightly off center and on the straight parts it
> occurs on center. I don't know how many vibratory cycles it takes to
> deplete the bearing interface of lubricant but I am certain it does.
Well, I'm talking about descending Mt Tam and the surrounding roads. I
descend reasonably fast, but speed varies widely from the short
straight sections to the hairpins. The bike is rarely moving in a
straight line.
Donald Gillies
>jobst....@stanfordalumni.org writes:
>Coasting on long descents is what causes bearing races to
>> develop dimples.
There you go again, jobst.
Coasting on long descents can _contribute_ to dimples, yes i believe
that. Was it the whole story with my TREK 2300 that developed dimples
before the first set of tires had worn out ?? No. How do I know ??
There just weren't any long descents on my trip to work. The San
Diego hills here are very curvey. There is only 1 descent on my trip,
and because the bike was used 100% for commuting - no club rides ever
- the focus was always to go quickly and so pedaling was employed 100%
of the time on that hill.
So your wild generalization is contradicted by direct field experience.
It's most likely that other contributing factors (e.g. significant
braking, rider weight, over tightening, and head tube flex) will
contribute to fretting and brinneling and cause indexed steering.
In my limited experience of 12 bikes owned, all my bikes with head
tubes > 24" (aluminum, reynolds 531) are indexed, none of the bikes
with shorter head tubes are (reynolds 531, 501, carbon steel).
That's some empirical data to think about.
I'll let you draw new conclusions.
- Don Gillies
San Diego, CA
Donald Gillies
>"Richard Ney" <r...@pobox.com> writes:
>>jobst....@stanfordalumni.org writes:
>In my limited experience of 12 bikes owned, all my bikes with head
>tubes > 24" (aluminum x 1, reynolds 531 x 2) are indexed, none of the
>bikes with shorter head tubes are (reynolds 531 x 4, 501 x 1, tange x
>1, carbon steel x 1).
I take that back. One bike with a cast steel head tube (TREK 500) and
a 24" frameset and a cheap tange headset has never indexed.
All of the headsets that I have rebuilt have never indexed. So for
me, lubrication depletion and head tube flex are more a suspect than
long straight coasting descents.
I have seven headsets disassembled ("dis") off-bike awaiting replating
right now. I am in an optimal situation to comment on the quality of
the bearing surfaces right now, and can provide pictoral evidence if
needed.
state headset state bike size
wrench
============================================================
dis ofmega indexed unknown, but i can find out.
dis campy not indexed unknown
dis campy not indexed unknown
owned (*) tange alum indexed 24 TREK 2300 1998 cast AL head-tube
dis brampton indexed 24.5 raleigh competition 1967 r531
owned tange steel not indexed 24 TREK 500 1984 cast steel head-tube
owned campy indexed 24.5 raleigh professional 1974 r531
dis campy not indexed 23.5 raleigh international 1974 r531
dis campy not indexed 23.5 raleigh international 1974 r531
dis campy not indexed 23.5 raleigh international 1974 r531
gone me tange not indexed 23.5 1977 SEKAI 2500 tange No.2
owned campy not indexed 22 1974 ALAN of ITALY aluminum
owned campy victory not indexed 22 1984 TREK 510 r501
owned brampton not indexed 22.5 raleigh competition 1973 r531
gone me brampton? not indexed 21.5 raleigh gran prix 1972 hi-carbon st
============================================================
(*) Chain Reaction Bicycles
jobst....@stanfordalumni.org
I think that unless you are moving slowly, less than 20mph, steering
is straight ahead long enough to cause fretting wear. What seems like
a continuously curvy road has longer straight sections than one
suspects. The roads in the pictures below are some of those.
http://tinyurl.com/pd86
http://tinyurl.com/xaco
Jobst Brandt
jobst....@stanfordalumni.org
jobst....@stanfordalumni.org
>> In my limited experience of 12 bikes owned, all my bikes with head
>> tubes > 24" (aluminum x 1, Reynolds 531 x 2) are indexed, none of
>> the bikes with shorter head tubes are (Reynolds 531 x 4, 501 x 1,
>> Tange x 1, carbon steel x 1).
> I take that back. One bike with a cast steel head tube (TREK 500)
> and a 24" frame and a cheap Tange headset has never indexed.
> All of the headsets that I have rebuilt have never indexed. So for
> me, lubrication depletion and head tube flex are more a suspect than
> long straight coasting descents.
When you say "indexed" I take it you mean there are dimples in the two
facing races discretely located where the bearing balls reside in
straight ahead riding. How do they choose this location and why are
there no dimples elsewhere? I propose it is because straight ahead is
the most common position. That this occurs while descending is only
the most common place where rapid vibratory bearing motion occurs, not
the only place where it occurs. A fast rider on any flat course can
develop bearing damage although it is highly unlikely to occur while
climbing, the speed being to low to not make significant steering
motions that would replenish lubricant. I think the emphasis got a
bit shifted here to descending.
> I have seven headsets disassembled ("dis") off-bike awaiting
> replating right now. I am in an optimal situation to comment on the
> quality of the bearing surfaces right now, and can provide pictoral
> evidence if needed.
I don't doubt your assessment. By the way, did you take a careful
look at the upper head bearing. These often have dimples as well
although not as deep.
Jobst Brandt
jobst....@stanfordalumni.org
Jay Hill
If a headset with a dimpled upper head race is allowed to get very bad,
can it actually deform the head tube?
Chris Zacho The Wheelman
AND replacing the bottom caged balls with the correct number and size of
loose (uncaged) balls cures the problem completely.
Now whenever I get a new headset (which is rare), this is the first
thing I do. Never had a problem with "indexing" again.
- -
"May you have the wind at your back.
And a really low gear for the hills!"
Chris Zacho ~ "Your Friendly Neighborhood Wheelman"
Chris'Z Corner
http://www.geocities.com/czcorner
Chris Zacho The Wheelman
realised he's using a cartridge bearing headset!
Please ignore my previous reply on this thread <sheepish grin>
Francesco Devittori
> Guess I'm staying up too late! Just re-read the original post and
> realised he's using a cartridge bearing headset!
>
> Please ignore my previous reply on this thread <sheepish grin>
>
Thanks to everybody for the suggestions! I think that as soon as my
wallet will be a bit less empty a new headset will be the solution!
Francesco
jobst....@stanfordalumni.org
> Actually, I have found that many times simply cleaning and
> re-greasing AND replacing the bottom caged balls with the correct
> number and size of loose (uncaged) balls cures the problem
> completely.
What do you mean by "correct number" and what does this do to ball
spacing? In a typical earing with cage, 20 balls occupy the race,
without a cage there is space for 22. Thus there is a two ball gap,
most likely at the front (highest point).
> Now whenever I get a new headset (which is rare), this is the first
> thing I do. Never had a problem with "indexing" again.
Filling a worn head bearing with 22 balls has been done often. My
experience is that a new set of dimples develop, usually symmetrically
about the front most dimple and you are back where you started in the
same or lesser riding distance.
To what do you attribute the improvement that you claim to experience?
Jobst Brandt
jobst....@stanfordalumni.org