Handlebars do not rotate smoothly

Reid Priedhorsky said:

Hello,

My handlebars rotate freely but have a number of "sweet
spots", i.e. there are regularly spaced places where the
bars will stay, but leaving the bars in between is
difficult (they will fall into one of the "sweet spots"😉.
One of these "sweet spots" is straight ahead. This problem
is quite obvious when off the bike and examining it, but
while riding it is noticeable only occasionally and then
barely. It's been present for maybe 3-4 years.

My questions:

1. Can I continue to ignore it as I've been doing?

2. I assume that there are worn bearing and/or bearing
surfaces somewhere. Is it possible to determine which
without disassembly?

3. If it's the bearing surfaces, how difficult is the
repair (especially considering I have only fairly basic
bike tools)? Would it be an expensive repair to have a
shop do? Do I need a new headset?

As you surmise, the headset bearings are shot. If it's a
conventional headset, buy a new one and have a decent bike
shop fit it with the correct pressing tools. For really
nasty bikes and chromed steel headset cups you can try a
block of wood and a hammer, but avoid this method for
anything nice.

If you're really lucky the headset will have cartridge
bearings (newer Shimano) or replaceable races (Stronglight)
and you can replace the worn parts without having to change
those parts that are pressed into the frame.

The headset will keep going for a long time like this
without any major effect on handling, but keep an eye on it.
If the bike still rides hands-off easily, it's probably OK.

The races have become "brinneled" That is, the constant
pounding from the road has banged dents in the bearing
races. The balls are settling into these dents, giving your
bike the "indexed steering". You can either replace the
headset, or you may be able to repair the one you have, if
you know how to work on ball bearings.

To do the latter, you need to disassemble the headset,
remove the lower bearing cage and pop out one of the
bearings. Take it to your LBS and get a bunch of balls the
same size, and repack the headset using the new loose balls
on the bottom bearing. You can still keep the retainer on
the top bearing, it takes no pounding.

Since loose balls are not held rigidly in place, they don't
always bang into the same place on the headset race. Since
the cage is no longer taking up room inside the bearing,
there are also more of them to absorb the impacts. Whenever
I get a new headset, the _first_ thing I do is replace the
caged bottom bearings with loose balls Unless it's a roller
bearing, of course, which doesn't suffer from this problem.

- -

"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 ↗

On Sat, 27 Mar 2004 20:12:40 -0500 (EST), [email hidden]

(Chris Zacho 'The Wheelman') said:

The races have become "brinneled" That is, the
constant pounding from the road has banged dents in
the bearing races.

Oh man, now you did it!!!! I wonder how long the engineering
discussion of the difference between fretting and
brinnelling (sp?) will be this go 'round?

yarchive.nethead bearing.htmlOpen ↗

(Chris Zacho 'The Wheelman') said:

The races have become "brinneled" That is, the
constant pounding from the road has banged dents in
the bearing races.

As has been discussed many times, that's not the cause.
Indeed, these dents can appear in headsets of bikes that
have never been ridden but have been clamped to roof racks
on pro team cars for hundreds of kilometers at a time.

Quoted message said:

The balls are settling into these dents, giving your bike
the "indexed steering". You can either replace the
headset, or you may be able to repair the one you have, if
you know how to work on ball bearings.

To do the latter, you need to disassemble the headset,
remove the lower bearing cage and pop out one of the
bearings. Take it to your LBS and get a bunch of balls the
same size, and repack the headset using the new loose
balls on the bottom bearing.

A temporary fix, but it does sort of work fof a while

Quoted message said:

You can still keep the retainer on the top bearing, it
takes no pounding.

And yet the upper bearing of headsets has also been known to
develop these problems.

Quoted message said:

Since loose balls are not held rigidly in place, they
don't always bang into the same place on the headset race.
Since the cage is no longer taking up room inside the
bearing, there are also more of them to absorb the
impacts. Whenever I get a new headset, the _first_ thing I
do is replace the caged bottom bearings with loose balls
Unless it's a roller bearing, of course, which doesn't
suffer from this problem.

As has been pointed out in several previous threads, roller
bearing headsets have other problems (although I have
personally had good results with a Tange Rollerball headset
which has been in service almost 8 years and has been
regreased once).

Chris Zacho The Wheelman said:

The races have become "brinneled" That is, the constant
pounding from the road has banged dents in the bearing
races. The balls are settling into these dents, giving
your bike the "indexed steering". You can either replace
the headset, or you may be able to repair the one you
have, if you know how to work on ball bearings....

Beware of the wrath (or at least stern correction) of Jobst
Brandt. <http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html>.

--
Tom Sherman - Quad Cities (Illinois Side)