rousseau

My 1-inch threaded headset sort of "locks in" to a straight ahead position every few days or so. When that happens I rotate the ball cartridges, and that makes it better, but then a good ride over a bumpy road results in "notching" again.

Question: As a somewhat heavy guy, am I simply doomed to eventually crunching the bearing balls in my headset? Or would this be an indication that the cups or races in the headset are scored? I haven't actually checked the cups or races for scoring yet. Still, I was wondering if this sort of phenomenon was easily diagnosed.

canopus 

Get a Stronglight A9 headset. There are either some NOS coming out or they started producing them again (I just order one for a rebuild). They can be had for about 40 to 60. Round balls for a headset are just not a good idea. Sometimes you can help the matter by removing the bearing cage and just inserting all loose bearings into the headset but I suspect it will still notch itself after a while. If it is notched already no amount of help will un-notch it.

Another option is to spend a lot of money on a Chris King Headset...

The reason headsets notch is really simply because there is a lot of force being applied to the race and ball in a concentrated area, The ball bearings in a headset don't really utilize the entire surface area of the race like a B.B. that is constantly turning, they pretty much stay in the same place in even after a turn.

Steev

Your races are brinnelled. Time for replacement.

rousseau

Thanks very much for the tip about the Stronglight A9. I've just ordered one from Ribble. A cursory Google search also produced numerous glowing reviews for it.

BCRider

But your new headset will do the same thing if it is not adjusted correctly when you install it. There needs to be some preload on the bearings so that when everything flexes under load that balls still all remain at least lightly in contact with the races. This lets all the balls share the load rather than putting it all onto one ball and one spot in the races.

To set the preload correctly you want to adjust it first until all the play is gone and the fork turns freely. Then tighten a little more so there is some drag. Turn the fork back and forth 15 or 20 times to aid in seating things if anything needs it. The final preload you go with should be such that you need to press against one of the fork legs with about 2 pounds of push with a finger to get it to begin to turn. At this preload setting everything should be smooth as silk when you hold onto and turn the bars.

After riding for a few hours worth lift the front and check the preload again by pushing on a fork leg. It may be a little lighter but if it all loosens up to where it feels like there's no preload drag at all anymore then re-tighten the preload so at least some of it comes back. I'd still aim for needing a 1.5 to 2 lb push on a leg to get the forks to begin to turn.

Overall too much preload will shorten the life of the bearings by a little out at the far end of their life. But too little preload so that the balls lose contact with the races will shorten the life a LOT and it'll show up a lot sooner. So if in doubt you want them to be slightly too tight a preload than too loose.

Grand Bois

Ribble is selling the new cartridge bearing version of the A-9, not the old needle bearing version.

prathmann

This is directly contrary to my experience. I've only had the "indexed steering" issue occur when using a headset that was adjusted with some amount of preload and never with a headset that was too loose. In particular the headset on our tandem developed this notched steering problem after only a few hours of use when adjusted with about the amount of preload you suggest above. I removed the cages so the ball bearings no longer line up with the dimples in the bearing race and made sure to adjust the headset to just barely take out the play and have had no more problems with that headset for the last three decades. Had a similar experience with my Bike Friday - it developed notched steering rather quickly with the amount of preload given at the factory but has not had any problems after I removed the cages and adjusted it for minimum play but no preload.

Note the following statement from:

https://sheldonbrown.com/brandt/indexed-steering.html
"More to the point, bearing dimples are not caused by impact, but rather by lubrication failure that occurs while riding straight ahead, giving the steering a preferred home position. Dimpling 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 occur less easily."

See the referenced site for more details.

desconhecido 

Supposedly, the Stronglight A9 headset is less susceptible to "indexed" steering than ball bearing headsets. Ben's has what appears to be the "traditional" A9 headset ($50) with roller bearings but only in black.

I seem to recall that Brandt doesn't like the A9 headset. You might consider that, if you care what Brandt thinks about headsets.

Grand Bois

I don't care what Jobst Brandt thinks about the A-9. I have them on three bikes. Roller bearnings do not index like balls do, but the steering feels a bit stiff on the stand when the adjustment is correct. I can't feel any difference while riding.

canopus 

Yeah, there's a lot about Brandt's mussings I don't care for. When I get to actually working on it I'll post a picture of my Gary Littlejohn that had to have some custom welding done to after it got mangled between a roadie and a tree. Needless to say the lower headtube was shot so I had it welded up and then faced it at the shop i worked at at the time (Good thing those facing dies are strong). I put in an A9 lower half and kept the BMX sized upper and put a GT headset top end there (The old Pro headset with the self-adjusting spring that keeps it tight all the time). It is still on the bike after 25 years and still smooth.

I dare say that, except for the B-10 (plastic A9), if you had a problem with the tapered bearing A9 it was probably because your headtube wasn't faced properly.

desconhecido 

Apparently, some people look at the design of the A9 and claim that it can't work properly. And yet, there are many, many of these headsets out there allowing bicycles to be ridden under almost any condition that a bicycle will face and they perform admirably. I have one and my only complaint is that it seems to need adjustment more often than I would like, but what I would like is "never," so maybe it's a personality disorder and I need to see a shrink rather than a bike mechanic. Maybe Brandt could recommend a good one.

BCRider

Prathman, what you describe sounds like adapting to a pre-existing condition. If so then the usual rules do not apply. I've had to do that too to make do with a part on an old bike that I was just fixing up. But it's not a good situation depite your success so far.

I may have also been a little overboard on the spec for 2 lbs of push at the fork leg to get it moving. But for lower to mid quality headsets I'd still want to see from 1 to 2 lbs of grab before the fork wanted to move. But the key is that when moving the travel should be easy and smooth with no notchiness or other signs of distress. If there are any then there's no option but to lighten it up a little if that fixes it. If it doesn't get any smoother up to the point of being too loose then I'd sigh and set it with some preload and expect it to either live or die as fate decrees. But under no circumstance would I set it to just barely no play since that just invites the risk of the bearings losing contact with the races and putting all the load on only one spot up top and one below. Bearings that are too loose and suffer from loss of ball or roller contact are a major reason for early bearing failure in cartridge style bearings. And it's no different with our situation. I'd rather put in a little too much preload than not enough as I said in my earlier post.

Mind you who knows what the dynamics are in a typical headset, head tube and steer tube system? It may well be that the whole thing is self balancing or some dynamic when riding is actually making the headset bearings tighter instead of just levering fore and aft. If that's the case then just setting to no play is fine. Or it may be that some bike and fork combinations tend to tighten up the axial load in use while others loosen or perhaps even just stay neutral. Without some fancy strain guage engineering test it's hard to say.

I'll close that in the last 15'ish years of setting all of around 25 to 30 headsets up that I've done I've always set them for some preload but also for a smooth rotation. And unlike your experience all of mine have survived and those that haven't been sold off are still going strong with no sign of any indexing or other issues. So it would appear to be a case of YMMV. And then there's the thought that when you set it to just no play perhaps you're far enough on the tight side of "just no play" that you're putting in an amount of preload that isn't that far from what I'm suggesting after all.... <shrugs>

prathmann

No, in both of the cases I mentioned the headsets were brand new when initially setup with some amount of preload (but my estimate is that it was a bit less than you recommended). Both failed rather quickly and it was only after they started to fail (i.e. became slightly notched) that I did any adapting by removing the cages so I could insert more balls and then adjusting the headsets more loosely.

But headset bearings operate in a very different mode than typical bearings. They do very little rotating at all and are instead loaded with a great deal of vibrational and fore/aft stress while remaining almost motionless with respect to angular rotation. I agree that crank and hub bearings should be setup with noticeable preload for the reason you cite, but my experience indicates that it should be avoided for headsets since they fail for a different reason - which was explained on Sheldon's website as referenced in my previous note.

No, as I indicated before, the way I set my headsets is for zero preload with minimum play (not "no play"). If, due to manufacturing tolerances, I can only get zero preload by still allowing there to be a detectable amount of play then that's the way I leave it. I've never had that cause a problem and the only issues that I've had with headsets have been those set up by others with preload.

rousseau

Yeah, I just removed the balls from the cage and put them back on loose, but the notch/score is there already, so it still doesn't feel completely smooth. Oh well, it'll do for now, and hopefully the new headset will arrive soon.

BCRider

Prathman, I guess it comes down to two methods. Mine works for me and yours works for you. One thing for sure is that I certainly can't argue with your success! But it goes against all I've learned about how bearings like to be treated. And that applies even after reading Brandt's theory on the matter of headset bearings and then reading a few other sources on bearing failure from a previous thread about this sort of stuff. Maybe it works for me because the types of rides I go on seldom see me riding in a long downhill coat with no perceptable steering. Or there may be something else at work to explain the issue. <shrugs>

I know that motorcycle headsets call for specific preloads in the ball style bearings such that there's a spec for them to move only when a certian amount of force from a spring style fish scale is used to pull on a specified part of the bars or forks to check for it. These use angular contact ball bearings very similar to the cartridge style bearings in bicycle headsets, just bigger. It's more likely to see a motorcycle on a tour riding along for many miles with no perceptable steering than a bicycle. I know because I did Highway 50 in Nevada a couple of years back. Seemed like DAYS of laser straight riding.... The steering head on the motorcycle is still fine. Again, I think there may be more to this than Brandt's theory. It would be nice to hear from a bearing engineer or two.

canopus 

Woo hoo. Got mine in from Ben's today, NOS Paramount A9 in black. Now I can start getting the SR300 back together.

BCRider, motorcycles typically have tapered bearings for headset bearings, similar in design to the A9. They usually don't use round bearings like a bicycle headset. Most tapered bearing specs call for preload on them.

BCRider

THESE days they do. But it wasn't that long ago that they all came with ball bearings. And a lot of dirt bikes and smaller non sport bikes still do.

vredstein

I had an A9 with what I think was an aluminum cups. They got indexed. I had a Stronglight O'Light threadless unit with the same roller bearing setup and it would never stay in adjustment. I've had better experience with Tange Levin units, replacing the caged bearings with loose balls.
Being open to the possibility the A9 problems were user error, it seems the Levin is more forgiving.

Grand Bois

You must have left out the steel races.

davidad

If you can find a shimano 1" threaded headset buy it. It solves the problems of road bike ball bearings fretting the races and leading to indexing.

canopus 

davidad, any specific shimano HS you are thinking of? Because the 600 I pulled off my ST was nicely indexed...

vredstein

Nope. both plastic retainers were sandwiched between a pair of loose races.

paulkal

I also always had problems with Shimano headsets.
The 105 and 600 headsets lasted maybe 6 months. The Stronglight lasted until one of the aluminium cups crakced, about 15 years.

davidad

Shimano Ultegra 600. I bought a few to make sure That I would have the bearings when I needed them. I ride about 14000 miles a year on two bikes and have had only two cartridges wear out. I only service them once every year or two.