AnjooLo

I recently bought a Centurion Sport DLX, some old school road bike from the early eighties. The bike has this weird habit of trying to force me to bike straight. What I mean by this is that when I turn, I have to overcome some kind of resistance to turn away from straight, but this resistance disappears as I turn away. It kind of feels like a cabinet door that snaps shut. The front steering keeps on trying to sink back into facing straight. It's hard to describe.

I've narrowed it down to some kind of fork-headset relationship. I've ruled out the handlebars, and associated cables, after taking it out and the front wheel still acting in this manner. I'm a bit reluctant to undo the headset and fork unless I have to.

Has anybody else ever seen/felt an issue with their steering like this? Anybody know what I have to remove/replace to stop this?

jsharr

Your headset is brinnelled. The balls have basically worn grooves or indentations in the races. If they are caged bearings, you can try going to loose bearings to see if you can get the bearings to sit in a new orientation. Your next choice is to replace the headset I believe.

Re-Cycle

Your headset cups are probably worn irregularly so the fork does not turn smoothly as you'd expect. A new headset can cost as little as $10 plus a little labor. Get it replaced.

Metzinger

By loose bearings, jsharr means removing the fork, and replacing the bearings that are likely currently held in cages, with new loose bearings. Usually, you can fit one more bearing into each race. Some have reported that in removing parts of the headset from the frame and fork, rotating them slightly, then reassembling creates a new smoother spot at dead centre.

LarDasse74

If it is brinelled, there is likely a set of dents in one of the races with dents the same number and spacing as the balls in the bearing cages. Removing the cages and packing with loose balls, one more than fit in the cage, will change the space between the balls so they no longer all hit the pits at the same time, and the problem is solved...


...IF the problem is brinelled bearing races.

AnjooLo

Is it likely that the bearings have worn grooves into the races at dead center?

LarDasse74

Likely that the bearings have worn dents in whatever position they are in when the handelbars are at dead centre, yes. It happens because the bike is usually ridden with the handlebars straight.

Here is an article by Jobst Brandt (on the SHeldon Brown.com site)

Asi

I wonder from what type of "cheese" is made the headset of a bike, because it's sure soft as cheese.

A 120mm ID ball bearing supports indefinite time, a weight of 15tons (wheel bearing on a large truck), and those do not Brinell themselves. Also bearings of a locomotive wheel are also heavily loaded and ideal for Brinell-ing (if you let the truck/train/airplane/car sit a longer time).

I can see that a 30mm thrust ball bearing (axial ball bearing) of 30mm diameter (about as a small headset) can withstand 43kN before Brinell-ing (that is C0 parameter, static load), 43kN=43000N~4300kg=4.3tons (metric ones, normal ones). https://www.skf.com/skf/productcatalo...ableName=1_8_1

That is 4.3TONS, a bike that is sitting has about 5-10kg load, or 50-80kg with a rider on it (on the headset). Anyway.. comparing it to 4.3tons..
I'd be much happier to overhaul a headset with an axial industrial bearing (industrial means the domain of use, not the size). For now I don't have problems with Brinell-ed raceways on bearing found on bike, but any bearing that develop this issue is a faulty bearing and an "exceptional" poor quality (on a bike or on a train, it doesn't matter)

And a small addition: Brinell was a man who developed a test for superficial durity (hardness) of metals, that is loading a 3kN on a small 10mm steel ball, onto the metal for testing, and measuring the diameter of the imprint circle on the tested metal - thus the hardness now is still measured in HRB (B from Brinell), HRC (Rockwell), HRV (Vickers), with small variations of what is measured (depth or diameter of the imprint, and the "punch": a sphere, a cone of diamond, or a square pyramid diamond)

Now if you want a headset to leave it to your nephews then put an industrial one. Otherwise just change the headset with another one, should last long enough, and it's the obvious fix and also the cheapest fix.

powers2b

You need a new headset because the one that is on your bike was over tightened by some ape fisted assembler back in the 80's.
I doubt it was "worn" into that position.
When you do replace the HS make sure to adjust it properly or have a mechanic do it if you don't know how.
This saves us from reading any future questions you may have that blame the frame for this recurring issue

Enjoy

cny-bikeman

Tight assembly is not the problem. Any mechanic who has seen a lot of the older type cone and cup headsets is familiar with "brinneling," which is why you see the fixes above that have been used for years. One can actually often see the dents in the lower headset cups. One generally can partially fix the problem just with work on the lower bearing. Of course the correct solution is a new headset.

Also, rather than addding one bearing to the amount in the cage as noted in an earlier post the proper count for a headset is to full up the entire cup until the last bearing crowds the others and then remove that one.

DaveSSS 

The headset is trash; get a new one. The problem is just as likely caused by undertightening. If ran loose, the bottom race gets dented as a result.

davidad

Replace the headset with a shimano 105 for threaded steering tubes.
If you read Brandt's article you will know the problem and this headset is the solution.

LarDasse74

I just added one more to my 'dummy' list as well. Read the Jobst Brandt article then reply back.

HillRider

Apparently you aren't familiar with the concept of "fretting corrosion".

cny-bikeman

Egg on my face noted. First I should have acknowledged that brinneling was not technically accurate - lazy use of the term. Also realize now I was misreading the bearing reference - I take it the poster was referring to the dia of the entire headset. Should have acknowledged the article as well - I certainly respect Brandt. I do stand by the fact that overtightening was not likely the cause. I did find that using loose balls provided a low budget fix, but a short-term and less than ideal one. I deleted the troublesome part of my post.

Asi

I may be, I'll look in a dictionary to find the appropriate translation in my language. Fretting as far as I know it's a temperature based tight assembly type with the use of dilatation (exterior diameter is heated to red, the inner part is freeze and assembly is done easly. When they cold/heat up, they realize a strong pressure between the pieces).

HillRider

No, that's not it at all. Read the Sheldon Brown link to the Jobst Brandt article on headsets referenced above.

Trakhak

At a Campagnolo seminar I attended in 1982, a Campy technician agressively asserted that all Campy headsets with dents in the races or cups got that way from overtightening by mechanics. Translation: they were getting tired of replacing headsets under warranty. Campy headsets were notorious for this problem at the time, much more so than the headsets found on cheaper bikes. At the time, I hypothesized that the problem arose more with Campy headsets because they were typically installed on racing bikes with steep headtube angles and short fork rakes, both of which would increase shock to the headset.

Now I know better. That Jobst Brandt article is fascinating.

DaveSSS 

I've read it. I'm also a mechanical engineer, so Brandt's got no better credentials than I do. I still don't agree that a lack of lubrication is the only possible cause for this problem. I've had a mild case of the problem with a Campy headset, years ago. I don't think it was ever overtightened and it was always well lubed. My routes always involved a reasonable number of turns and I know the fork got flopped from side to side before the start of every ride.

A headset that's too tight won't allow the fork to turn freely or self-center after a turn. Leave a headset too loose and the road vibration will beat it to death - just my opinion, not something I've ridden many miles testing.

The problem with old style headsets is getting all of the play out without overtighening. There is little margin for error. I guess the way to disprove the loose headset idea is to leave your headset loose and see if it causes any problems. If not, then I'm wrong.

What's lacking in the Brandt's response is how to tell exactly when the bearings are "too tight", if it's the only possible cause of this problem. I definitely don't want my fork rattling, nor do I want it binding. There is also no proof that riding a loose headset will not cause any damage. If Brandt had done a real-world test to prove his statement, I'd accept that evidence.

At least Brandt does note that the new angular contact cartridge bearings are less likely to suffer this problem. They are also much easier to adjust. All of my bikes have these new bearings. I'd be unlikely to buy a headset without them. I give my headsets all the preload tension they can take without causing drag that would not allow the wheel to self-center. I've never had bearing problem. The greater possibility with integrated headset is the outer bearing race beating up the bearing seat in the head tube, if ridden loose. This was a common problem in the early days of integrated headsets.

The information at this website certainly acknowledges brinelling of a bearing race being a distinct possibility.

https://www.nationalprecision.com/bearing_basics.html


FWIW, I've read Brandt's very old article on chain wear and proven some it to be wrong. He claims that only a chain with excessive elongation will damage cogs to the point that they won't mate with a new chain. I've proven that to be wrong with two different Campy chains and two different cassettes. A chain with only .2% elongation (in 6,000 miles) wore out my 19T steel cog on one cassette. Another chain with even less elongation (in 4,000 miles) wore out both the 19 and 21 tooth Ti cogs on another cassette. What that proved is that leaving any chain in use for too long can wear out the most-used cogs, so it won't mate with a new chain, even if the elongation is very small. The explanation probably probably lies in the fact that the cogs get worn-in to fit smaller diameter rollers. The roller OD on my chians was about .005 inch smaller after 6,000 miles.

jccaclimber

Giving you the benefit of the doubt, you're suffering a lost in translation. Read the article on Sheldon's page, sitting still leaned up against the wall isn't the problem. Industrial bearings are not going to differ significantly from a bicycle headset.