Andrew R Stewart 

I've started this thread as to not hijack another that tangented into the long time topic we've covered before, headset wear and is it Brinelling, fretting or false brinelling. I state right up front that I have mixed beliefs about this topic. I have what I feel is clear observation of one cause of "indexed" headsets but have been taken to task by others smarter then I about what was "really" going on.

I offer the Free Dictionary/Wikiepida descriptions. Note that there's some conflict WRT to Brinelling between it's description and what is said about it in the False brinelling text. No wonder some of us are still in the dark. Andy

brinelling

Fretting

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79pmooney

We should all be riding brakeless fix gears, do Peter Sagan quality wheelies and spin the bars a few revolutions. Pull this stunt on a regular basis. Maybe 5 times/mile. Our headsets wold last a lot longer.

Ben

Andrew R Stewart 

Except for those hard landings (from the wheelies). Andy (Who has seen a guy do a wheelie on rollers)

3alarmer 

...honestly, I was only curious about your proposed mechanism for brinelling in a headset that was "excessively" preloaded (whatever that is).

My own supposition (because as you say, there appears to be no definitive answer), is that a lot of headset brinelling is of the false variety. The bearings and race surfaces are hard enough that it's difficult to picture denting in the races caused by excessive preload in a good quality headset. Certainly I have replaced my fair share of headsets on old restorations over the years, and the function of headset bearings as more or less stationary bearings (unlike wheel and crank bearings) wold appear to render them subject to exactly this sort of wear.

Mostly, I think that telling people to kind of sneak up on the adjustment of a headset by gradually tightening it results in a lot of bicycles that handle less well than preloading them to where the fork just flops when a wheel is inserted. I know I can feel the difference, and I'm not a particularly sensitive individual.

rccardr 

Hunh.
When I saw the title on this post I thought it was about someone being dismayed over the condition of their headset cups.

HillRider

The real difference, based on the definitions Andy provided, is that "Brinelling" entails no loss of material while fretting and false Brinelling do lead to material loss at the contact points. Brinelling, I believe, is based on the Brinell Hardness Test which pushes a small hardened ball into the test surface under a known load and measures the resultant depression. The larger the depression the softer the material but no material is lost in this test.

3alarmer 

...tell me about it. I just took a Campagnolo alloy headset off a nice Casati I'm repainting and it was history on the bottom half.

Andrew R Stewart 

Dave is getting to my point of there being conflicts in the published descriptions I offered. The first, brinelling, says corrosion is in play, and in my view corrosion means some "loss", or maybe transfer from one form to another, of base material is going on. The third, False Brinelling, says brinelling is material deformation with no loss. Hence my claim of conflict and the resulting confusion we seem to have.

It's been my many year understanding that brinelling is what the third description says. A localized dent from the contact (sharp impact or mere pressure) that the ball offers the track. IME more common on the cone then the cup but on either. More common on the lower bearing then the upper, IMO due to the greater pressure acting on the lower. I never heard of the term false brinelling or fretting until I began reading/posting on this forum. I believe it was Francis Bollag that first made these terms known to me. It was he (and a few others that I forget who) that suggested the "indexed" headsets I saw were from fretting.

Now I had seen what I now believe is fretting in/on a headset ball track before, I just didn't have any special term for it other then corrosion. I've seem many headsets with discolored spots on the tracks centered on where each ball sits. These spots are larger then a point but smaller then the ball's diameter usually but don't have any discernable indentation, and sometimes don't even have a felt indexing. (I've seen much the same on hub and BB bearings too maybe not as common though).

As I began to explore my experiences with these new terms I believed that fretting, false brinelling, might be the cause of some indexing I've seen but not all. And this is the base of my mixed thoughts that I first alluded to. When I see a still unused headset in a still not ridden bike with indents on the ball track, plenty of grease and no usual signs of corrosion I have a hard time calling them (the dents) fretting/false brinelling. I have all the belief that these dents are pressure/impact caused, or brinelling. From what incident (bad pun) I can't say, but with no other evidence of corrosion (or that micro welding thing some have also said is at play) not fretting/False brinelling.

The subject of how to "best" adjust a angular contact bearing is a whole another different topic, all be it a topic that might influence long term performance and effects. I've come along for 45+ years with my understanding about this. Others have their views. When we see bad wear and the "other adjustment condition" we place blame on that other method. I consider this to be human nature to a degree. We view the world from our point of view. In this forum I can live with others having their view but on the bikes I service and ride it's my view and methods that I follow. Andy

fietsbob

See them in shop repairs balls bang in the same spot overtime ,
result; 'index steering'
headset loose , And so impact has space ..


I replaced the frets on my 96 year old mandolin, this year..
steel string hit same spot in the frets many million times ..






...

Andrew R Stewart 

Yes, for all of Campy's rep. for high grade bearings their headsets are really poor. When new they were among the smoothest for their time (and I'm thinking about the Record, Super Record and Pista versions of the 1960s, 1970s and early 1980s). But many suffered indexing far sooner then the competition did. I attributed much of this to the overtightened adjustment that a really smooth bearing made so easy to end up with. We were taught to creep up on the adjustment point from a loose/rocking side because rocking (with the completely assembled bike and the front brake locked on) is a black and white feeling yet approaching from the too tight side is one of trying to discern how much friction is too much through the massive leverage the bars have over the bearing (again about 15:1). Remember that with quill stems there's a slight shortening of the steerer when the wedge it tightened within the steerer, so ang headset adjustment made prior to the stem's tightening is, IMO, a false one. We saw the Campy headsets we installed did tend to run longer before indenting but they still indexed sooner then we were happy with. Andy

Andrew R Stewart 

FB- So you pressed the strings against the frets many millions of times? I thought that frets (in a stringed instrument world) are the raised ridges that the string is pressed against to effect a change of tone/note. I thought hat the parts of that the strings contact all the time, and thus might see millions of cycles of pressure, are the nut at the top end of the neck and the bridge on the body. It is also my layman's understanding that the strings don't hop or bounce off of these two contact points, so no impact is at play. I suspect that the wearing away of these two points, and the frets too, are from common abrasion. The string acts as a sanding/cutting tool of sorts. Andy

fietsbob

The typical fret wire is softer than the carbon steel string ,
on the lower frequency vibrating strings the bronze winding wire around the steel core wire
adding mass to produce desired frequency vibrations , at a lower tension,
is softer than the fret wire so the opposite happens ..

3alarmer 

...I check all my bearing adjustments for a final result after the wheels are installed on the bike. This includes headset bearings and wheel hub bearings. I don't see any other way to get an approximate feel for what's going on in use, which is what I'm after. How do you feel about the fork flop test ? It's what I use, and it gives me a real world approximation of what's goin g on in the headset bearings.

If you've got something else that works better for you, I'm fine with that. But it does seem to me that all the endless discussion we see here on teh Biekforums about wheel bearings running too tightly because they are compressed by skewers, and headsets that are overloaded by final stem installation might be remedied by the simple expedient of checking these things when installed on the bicycle...like when you install one of those Raleigh Sports front wheels with no locknuts and have to do the final adjustment in the fork.

WizardOfBoz

Yeah, my impression of Brinnelling was always an imprint left in metal due to impact. In fact, that's how metals are tested for hardness. Something (a pyramid shaped diamond, or a hardened ball) is pressed into the tested metal with a known force or energy. The size of the "divot" is measured and you look the size up in a table and get a Brinnell hardness.

Likewise, in a machine shop, one refers to bearings which were improperly handled (shock loaded, or pressed in or out with the press force transmitted through the balls) and which have divots as being "Brinnelled".

HillRider

If you don't mind, I'm going to take this thread off on a bit of a related tangent. We've been discussing loose or caged ball headsets. How about cartridge bearing headsets and their geometry and wear characteristics?

I have a Chris King threadless headset on one bike with over 44,000 miles on it and it's as smooth as the day it was installed with absolutely no indexing at all. I set a modest preload (~5-10 inch-pounds) when I adjust it per Chris King's instruction sheet. This headset has been subject to some of Penn DOT's worst maintained roads so it hasn't been babied at all.

I had an FSA Orbit X cartridge bearing headset on another bike and after 36,000 miles it got to the point where it couldn't be adjust properly. It was either too loose or bound up with nothing in between. It wasn't indexed, just not adjustable. I replaced it with a Velo Orange Gran Cru that now has 11.000 miles and is still glass smooth.

My point is that these cartridge bearing headsets have far outlasted any loose/carged bearing headset I've ever owned and yes, I know how to adjust that type. There must be a reason.

fietsbob

One big advantage of cartridge bearing headsets is the bearing adjustment
is not going to get loose ..
spaces, bearings between the 2 races is fixed in the bearing making factory,

In CK's case, they make them themselves, too..

Steelman54 

I was not clear on the question here, but i'll offer the following:

1. True brinelling - caused by impact which eventually leads to deformation of the bearing race or ball; hence indentations; therefore notched steering, unable to set clearance. I think this the common form of brinelling a headset would see. I have seen this only once in many years of working materials issues.
2. False brinelling - relative motion of the bearing against the race that the lubricant/grease cannot withstand, eventually damages the race and/or ball. The auto industry had this problem many years ago from shipping autos on trains.
3. Fretting - relative motion between 2 parts, usually unlubricated, but leads to localized damage of the material.

In all cases above, cracks (typically fatigue) can initiate and lead to worse problems.

Other than possible true brinelling of a headset, hard to imagine 2 or 3 being too much of an issue on a bicycle, but i don't know everything.

Hope this helps answer whatever anyone was thinking.

Mike

mrv 

Interesting topic @Andy R Stewart - love reading what you have to say.
I have never heard of brinelling being related to corrosion: your definition - " (Metallurgy) a localized surface corrosion; a cause of damage to bearings "
Consulting the Great and Mighty Google, neither of these links mention corrosion with the Brinell Harness Test:
- wikipedia: https://en.wikipedia.org/wiki/Brinell_scale
- https://www.corrosionpedia.com/defin...inell-hardness (CorrosionPedia !! Ha! Never would have thought such a thing existed!)

So me and my masters of engineering degree that my parents bought me decades ago, we don't like Brinelling associated with corrosion. But if a metallurgists chimes in says - "is so associated!" - then I will completely defer and change my mind in a snap.
When I read the definition of fretting - that sure sounds like what happens over time to a headset. Where Brinelling would be "Fat Tony" wrenching hard on your headset at the shop and leaving it dented, and therefore indexed. False brinelling is completely new to me. So I'll re-read your original post a couple more dozen times.

I'll read up some more on all three definitions, probably abusing the vast technical resources available to me through my employer. If I think I can come up with a coherent summary, I'll do my best to post some kind of update.

OK - got to get back to work. Cheers.

Andrew R Stewart 

I don't have all, or even the right, answers all the time but... One aspect of fretting that I have read is the metal to metal contact required for the corrosion or micro welding to happen and the break down and lube helping to prevent this direct metal to metal contact. I suspect that bearings that don't suffer the loss/breakdown of the lube will not also suffer fretting/false brinelling as readily as a headset where this lube lack more easily happens. Bearings that are better sealed, that are more frequently serviced, that are kept out of the high pressure exposure that can drive contaminants in and lube out will be less likely to end up with fretting or corrosion. I suspect that the base materials have some influence here too.

I just yesterday overhauled a Chris King headset on a Spectrum that has, maybe, a few 10s of thousands of miles on it. It predates my at the shop and I have serviced this bike a few times already, but not yet opened up the headset's bearings only wiping off old and wiping on new during tune ups. The bearings run real smooth and easily after cleaning out the old. The seals are still well formed with no thin spots or tears. This is much like my couple of personal CKs that I have done before. But I have dealt with a couple that were really trashed. Both didn't get serviced for a long time and run loose. Both were pretty indexed. I feel that one's use can over come good design, maybe it takes longer but any bearing can be ruined. Andy

Andrew R Stewart 

May I ask what type of bearing contact designs/angles are being referenced as we talk about "cartridge" bearings please? As example the Chris King cartridge bearings are angular contact ones. So much of the aspects that we work with on cup and cone bearings are needed with CK's. Most of the other brands of hubs that I have dealt with use radial contact designs, having minimal axial load capacity to speak of. Not what we want in a headset where the vast majority of the forces run axially.

I'm finding this thread pretty interesting, both in what is said and who's posting. Andy

Cassave

......and surprisingly inconsistent. I have a 1982 SR headset that's been in service continually since new. It's still smooth, perfect races, rarely serviced and on a bike that gets ridden very hard.
I had another NOS SR headset I installed on a bike I built in 2008, it was junk by the end of the first year. The lower race and cup were unusable.

Racing Dan

https://www.mx.nsk.com/downloads/americas_bearing/BearingDoctor_for_web.pdf

https://www.ntn-snr.com/sites/defaul...earings_en.pdf

https://donoupoglou.gr/wp/wp-content/uploads/2015/03/catb3001e.pdf

Andrew R Stewart 

Racing Dan- Some pretty cool points and info in your links. I liked the photos of damage and then compared them to what I see in the shop. I will say that by the time shop usually sees a going bad bearing the damage is pretty well along. Most riders only react when the bike is no longer nice to ride. Andy