indexed steering

[kgatwork]

Francesco Devit wrote:
> 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.



--

 

[Francesco Devittori]

kgatwork wrote:
> Francesco Devit wrote:
> > 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.

 

[kgatwork]

Francesco Devit wrote:
> kgatwork wrote:
> > Francesco Devit wrote:
> > > 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.



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]

[email protected] wrote:

<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]

[email protected] writes:

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?

 

[[email protected]]

Richard Ney writes:

>> 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.

http://tinyurl.com/2gbsj

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 protected]

 

[Richard Ney]

[email protected] writes:

>>> 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]

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

>[email protected] 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

 

[[email protected]]

Richard Ney <[email protected]> writes:

>>>> 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.

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
[email protected]

 

[Donald Gillies]

[email protected] (Donald Gillies) writes:

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

>>[email protected] 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

- Don Gillies
San Diego, CA

 

[[email protected]]

Donald Gillies <[email protected]> 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" 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
[email protected]

 

[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]

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
http://www.geocities.com/czcorner

 

[Chris Zacho The Wheelman]

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
http://www.geocities.com/czcorner

 

[Francesco Devittori]

Chris Zacho The Wheelman wrote:
> 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

 

[[email protected]]

Chris Zacho "The Wheelman" <[email protected]> writes:

> 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
[email protected]