indexed steering

kgatwork said:

Francesco Devit 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

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.

--

no, it should have seen the light in 1994, just one year or
so before the 7700. It doesn't smell titanium.

Quoted post said:

Originally posted by Francesco Devit

Bkgatwork said:

Francesco Devit 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

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.

--

no, it should have seen the light in 1994, just one year or
so before the 7700. It doesn't smell titanium. [/B]

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.

[email hidden] wrote:

<snip>

Quoted message said:

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.

[email hidden] writes:

Coasting on long descents is what causes bearing races to

Quoted message said:

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?

Richard Ney said:

Quoted message said:

Coasting on long descents is what causes bearing races to
develop dimples.

Quoted message said:

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.

tinyurl.com2gbsjOpen ↗

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 [email hidden]

Quoted message said:

Quoted message said:

Quoted message said:

Coasting on long descents is what causes bearing races
to develop dimples.

Quoted message said:

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.

Richard Ney said:

[email hidden] writes:

Quoted message said:

Coasting on long descents is what causes bearing races to

Quoted message said:

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) said:

"Richard Ney" <[email hidden]> writes:

Quoted message said:

Quoted message said:

[email hidden] writes:

Quoted message said:

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

- Don Gillies San Diego, CA

Richard Ney said:

Quoted message said:

Quoted message said:

> Coasting on long descents is what causes bearing races
> to develop dimples.

Quoted message said:

Quoted message said:

Quoted message said:

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?

Quoted message said:

Quoted message said:

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.

Quoted message said:

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.

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.

tinyurl.compd86Open ↗ tinyurl.comxacoOpen ↗

Jobst Brandt [email hidden]

Donald Gillies said:

Quoted message said:

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).

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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 [email hidden]

If a headset with a dimpled upper head race is allowed to
get very bad, can it actually deform the head tube?

Actually, I have found that many times simply cleaning and
regreasing 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 geocities.comczcornerOpen ↗

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>

- -

"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 geocities.comczcornerOpen ↗

Chris Zacho The Wheelman said:

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

Chris Zacho 'The Wheelman said:

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).

Quoted message said:

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 [email hidden]