IPassGas

I cleaned/greased my tandem headset today, it felt fine but I have often wondered... On threadless headsets with cartridge bearings (e.g. FSA Orbit X), does random repositioning of the cartridge after cleaning help significantly in mitigation of indexing? Perhaps, independent of the initial position of the outer race, it rotates to the same position and brinelling fretting continues at same spot. I have look for an answer in previous threads, this one was interesting (fretting v brinelling) but did not address my question.

https://www.bikeforums.net/bicycle-m...rinelling.html

FBinNY 

It definitely helps with pressed in cup/cone headaets by randomizing the orientation of the elements.

With cartridge bearings it will also help, but possibly less so, because the races are free to creep back to alignment.

In any case, a key word here is "significantly". I'd rank this as probably helps, maybe not so much, but can't hurt. Kind of akin to low dose aspirin for seniors.

davidad

Indexed steering (Jobst Brandt) (yarchive.net) Old, but reliable ifo from a ghost.

Trakhak

Has anyone experienced "indexing" of threadless headsets? I've had a few threaded headsets that developed dents, but none of my bikes with threadless headsets have, and I'm put at least as many miles on the latter.

IPassGas

I have not experienced this in my travels on a single touring bike. However, on a tandem, heavily loaded for touring at least twice over 100K miles with 1.25" headset. It is annoying when it develops, but easily fixed with a new headset. In the past I have not been as maintenance conscious with the headset, thus my question. Thanks FBinNY...baby aspirin seems appropriate. The reference to Brandt's comments is (as always) interesting...I must assimilate further. Perhaps, tighten the headset to just bring in contact and then 1/4 turn more...don't wish to make the grease feel unwelcomed

FBinNY 

We need to keep in mind the nature and causes of headset fretting, along with thinking about the changes to bikes over the last half century or so.

The primary cause of fretting wear in headsets is vibration. BITD, we were riding on high tensile forks, usually either Reynolds or Columbus, and riding HP tires, often tubulars. This combination does a great job creating and transmitting high frequency vibration of decent strength. Modern high end bikes no longer use steel forks and these new forks, especially CF, do not transmit high frequency vibration well, so much less gets to the headset, and we can consider better HS life as a fringe benefit.

Also, lubricants have continued to evolve, and the modern greases used are formulated to prevent or slow fretting wear. On my older bikes, still using "old tech" components, I'm also seeing improved headset life, and I mostly attribute that to the lubticants. (anti-fretting bearing greases that didn't exist in 1967)

mpetry912 

yes, it's a good idea to "index" the lower cup to put the wear zone 90 degrees out of phase, just pull the cup and the crown race, rotate them each 90 degrees, and re-assemble.

this trick will let you get years more use out of an older headset.

/markp

FBinNY 

There is no "wear zone" since the headset makes 360 degree contact unless the headtube is bent. That said, moving either element a few degrees mismatches the upper and lower elements so you don't have 30+ top and bottom wear zones in alignment.

mpetry912 

really ? Take a look at at lower headset cup or crown race that has 30 years of riding on it. The wear is concentrated at the "back" if you will. the 6 oclock position.

/markp

FBinNY 

I've personally fretted a decent number of headsets over the years, plus have seen countless others.

All of mine, and most of the others had uniform or near uniform wear patterns.

If I see a pattern like what you describe, I'd consider it evidence of a bent steerer tube.

That said, if you see uneven wear like you describe, rotate one part 178 degrees, and the other 182 degrees, so you solve both issues.

choddo

That was both informative and entertaining. Quite a character and I love the naivety of the early internet just sharing email addresses with wanton abandon.

In that link he says the dimples are deepest at front & back, fading to near zero to left and right because of the plane of the vibration.

But I guess the effect on feel when turning the fork will be the same wherever they are, which is why you’re saying the 90° rotation won’t help?

FBinNY 

Partly. The key that you have matched dimples top and bottom. Assuming 36 balls (for easy math) dimples every 10 degrees. So move either part 5 degrees (or 85 degrees) so the dimples don't align.

Another solution is to remove 2 balls on your new headset and replace them with a wooden spacer. Then occasionally remove the bar and brake, and spin the fork one turn. That will move the balls to new positions and randomize the fretting.

mpetry912 

I'd have to get out my protractor. Usually an eyeball 90 degrees is fine at least for me

/markp

Trakhak

In addition to a bent steerer tube, such a pattern could also be the result of riding with the headset a tiny bit loose (not uncommon) or of the bottom of the head tube having developed a slightly oval shape, with the major axis oriented fore/aft (less common).

A Campagnolo rep who conducted a seminar for local shops back in the mid-1970s insisted that if a Campy headset developed dents, it was the fault of the assembler. He made that assertion after having a volunteer adjust a loose Campy headset. "You just performed a hardness test!," he said gleefully to the embarrassed shop guy.

He probably would have said that no matter how the guy did the adjustment, since the proper technique he demonstrated looked like that of a guy defusing a bomb.

It didn't occur to any of us to say, "I use the same technique for all the headsets I adjust. Why is it that it seems to be a problem with Campy headsets especially?"

My guesses: Campy headsets were mostly used on Italian racing bikes, which tended to have steeper head angles; the riders who owned Italian racing bikes, at least back then, were generally the ones who rode the most miles.

JohnDThompson 

Or the crown race seat and/or head tube ends needing milling.

FBinNY 

You missed my point. I was responding to someone who suggested rotating 180 degreed. My point is that all that's needed is to put the upper and lower race out of phase by about half the distance between balls.

FBinNY 

Yes, any condition which allowed the races to not be parallel.

FBinNY 

Another name for this type of fretting is "FALSE BRINNELLING". Aptly chosen because so many attribute it to the wrong cause. BITD most in the bike community bought into that myth, which is still very much alive today.


FWIW steel ball hardness tests are only for softer metals like brass. Hardened steel dimple tests are done with a diamond.

mpetry912 

I got your point bro ! when I did this on an old Cinelli, I split the angles - rotating the crown race about 90 degrees clockwise, and the lower cup about 90 degrees counterclockwise.

As you say, as long as the two wear areas are out of phase, it's fine.

I was just showing off my fancy protractor

/markp

choddo

I don’t really understand this properly yet but wouldn’t that keep them in phase as it frets the most front and back so now the deepest dimples are left & right on both?

mpetry912 

3
yup. puts the "old" wear zones in a less used position so as to get another 10 years out of the headset.lower cup and crown race

/markp

FBinNY 

I explained (I thought) fairly clearly early in the thread, but will try again.

Forget about front, back, or side wear zones. Think ONLY about the dimples and the spaces between them. You want to move either race, a bit so it's dimples now align with the other race's spaces.

It's that simple.

Bike Gremlin

Could it be explained by the front wheel's spray? The back of the steerer is where most of the water and mud gets sprayed by the front wheel, at an angle just right to enter the bearing as much as possible.