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What causes headsets to index?n.m.(13 posts)

What causes headsets to index?n.m.koala
Sep 3, 2003 5:14 PM
Being too tight or running dry can do it...cory
Sep 3, 2003 5:55 PM
"Indexing" is actually a pretty new term for it--it came along as a joke after index shifting replaced friction, because...you get the idea.
The most common cause may be tightening it too much, so the balls make an impression in the race. From then on, you'll feel it when they roll over the dimples. Sometimes, though, they can feel "indexed" when they're not damaged, because they're too tight or just have no grease in 'em. Try lubing and readjusting before you toss it.
Also from hanging from front wheel....theweasonator
Sep 3, 2003 6:28 PM
Like cory said, the bearings can get pitted (dented) and you feel these pits crunching together.

Mine "indexed" or tracked dead straight on. I learned the hard way and replaced the stock Tange headset on my Cannondale after the first year. Great excuse to get a King...
Never turning it more than 15 degrees, so take the brake off....Spunout
Sep 4, 2003 3:43 AM
and spin the forks around a few times. This will re-roll the bearings and races, distribute any wear, and you'll be fine.

That was an old trick learned from using Campagnolo super record headsets in the 80s.
Loose headsetwinstonc
Sep 3, 2003 10:18 PM
I once had the lockring on my threaded headset come loose. I rode it for a few miles to the nearest shop, but by that time, the rattling bearings had pounded indentations in the headset cups.
mostly wrong answers again...C-40
Sep 4, 2003 4:55 AM
The only reason that a headset "indexes" is due to a dented lower bearing race. The races get dented from riding the bike with the headset too loose. The bearings must be adjusted for ZERO play, with a slight preload from the top cap (assuming a threadless headset).

If the headset is noticeably indexing, cleaning and regreasing won't fix the damage. If the bearings are acutally dry, it might make the indexing less noticeable, though.

It would be darn hard to tighten a headset enough to dent the lower race, although a cheap OEM headset might be susceptible to such damage. Hanging the bike from it's front wheel won't hurt a thing.
Even if a headset is adjusted correctly.........MR_GRUMPY
Sep 4, 2003 6:25 AM
it will eventually "index". The normal bumps and bounces will "dent" the lower or even upper bearing race. A loose headset will just cause it to index much quicker.
If a headset is "dry", the bearings and or races will gaul, giving a rough feel.
Normally I yield to a guy named for his bike, but...cory
Sep 4, 2003 7:42 AM
Could be we're caught up in semantics here, but since "indexing" is a made-up term anyway, its definition is imprecise. Generally when I've heard people use it, they mean the bearings feel rough or notchy, and adjustment and lubrication can often fix that.
I agree about hanging by the front wheel, though. If that caused problems, I'd have 13 indexing headsets hanging in my garage right now.
Correct, C-40, and a headset can sometimes be salvaged byStraightblock
Sep 4, 2003 10:26 AM
replacing caged bearings with loose ball bearings of the same diameter (you'll need more than are in the retainers) or replacing loose balls with caged bearings, if you can find some that fit correctly. This changes the spacing of the bearings relative to the indentaions so they don't all drop into the dents at the same time.
one big pothole will do itDougSloan
Sep 4, 2003 7:10 AM
I had a headset, some cheap stock one on an older Bianchi, index the first time I hit a pothole in a race (could not see it, and the bastards ahead did not point it out). Hit pretty hard, hard enough to rotate my handlebars down in the stem clamp. Ruined the headset. Replaced it with a Chris King, and never had another problem.

Doug
.....so will tightening the headset with a pipewrench!Alexx
Sep 4, 2003 6:23 PM
Please, don't ask me how I know this to be true.....
re: What causes headsets to index?n.m.asgelle
Sep 4, 2003 7:47 AM
from the rec.bicycles FAQ http://draco.acs.uci.edu/rbfaq/FAQ/8f.13.html

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 and the blows were
more severe and direct, supported by no more than one or two balls.
Thanks all of you....koala
Sep 4, 2003 12:30 PM
I guess my Record headset with 4500 miles on it will go on the rain bike and my new frame will get a King. The Campy headset was supposedly adjusted correctly(always overhauled in winter) by my local bike shop. I used to be a guy who thought King headsets at 100 dollars was too much. Not anymore.