Unca_Sam

I was just riding along for the first time on a local singletrack when I came up to a log "bridge" (really just a 3'-4' section of log that had been flattened and stabilized) with a small patch of rocks on the far side at the bottom of a descent. I handled the feature poorly and gave my front end a good knock. Not too long later I noted that my headset felt loose while braking, and confirmed it. I hand tightened the adjustable cup and tried to tighten the locknut by hand as best as I could. A few miles, roots, and rocks later, the headset lost its adjustment once more, but this time I determined that the locknut was barely holding on. Eventually, I pulled a spacer on the fork and tried to get to better threads on the locknut to finish the ride. I pulled it all apart this morning for a diagnosis.

Abnormal wear on the pressed cup from loose adjustment?

Adjustable cup bearing wear.

Damaged threads on the top cup

4 rows of stripped threads on the locknut

Back of fork threading, roughness around keyway


Front of fork, damaged threading around the top cup spot, worn threads at the top

Worn areas circled.

I think I'd be kidding myself if I said I could keep riding this rigid MTB on our local rooty trails without replacing the headset. I'm beginning to think that the top cup has threads that are too worn to hold the preload, which is loading the locknut threading to failure. This is the second locknut that's stripped on this headset, and I'm probably lucky the fork threads aren't more damaged. I've never been happy with the headset as it seemed to lose it's adjustment easily even with appropriate washers and a new locknut, which is likely because of the worn top cup. The steerer is long enough that I'm using about 7mm of washers between the top cup and the locknut so the locknut has about 2mm of space before it bottoms out on the steerer. I believe the path forward is to pull the old headset hardware, chase the fork threading to clean up the threads, and reinstall a new headset. I do notwant to replace the fork, as it's original to the bike as built (and a pretty awesome Spinner MTB fork).

For these kinds of failings on a frame that will see earnest singletrack XC use, is a fresh headset likely to solve my problem? Would you continue to use a cup and cone headset, or would you look at a cartridge bearing headset and why?

I think I have some leeway on stack, and I'm going to grab those measurements now. While an obvious recommendation is to buy and install a Chris King gripnut, I'm not sure that the price is appropriate for my Kona Cinder Cone.

Final configuration

Unca_Sam

The head tube measures at 131mm, while the steerer is 170, which gives me 39mm of stack. 😧 so far most of the headsets I've been looking at are 41mm, so I'm not sure if I need a shorter stack or not.

Papa Tom

I may have missed something, but did you remove the bearings from the cup before you took the photo?

Unca_Sam

Of course I did! There was a full complement of caged 5/32" bearings in the cups before I removed them to clean the grease from the cups to inspect the bearing race.

mpetry912 

good pics ! you have a bit of brinnelling in the lower cup, it's to be expected.

The steerer tube threads look OK, just brush them out and keep on smiling.

here's what I suggest - pop out the lower headset cup and turn it 90 degrees, re-install.

then take the crown race (which is the part that takes a beating) and rotate it 90 degrees in the opposite direction.

that puts the two wear areas out of phase with each other. I've used this trick on "beyond rare" Cinelli headsets with good results. Replacement parts were just not availalble

you can make a very acceptable headset cup press from some 3/8 threaded rod and big washers. use a wood block to protect the cups.

If you really want the most durable headset, you want a Stronglight A-9, old roller bearing type. Nearly indestructable. round the world type survivable part.

you might only need the lower cup, bearing assy and crown race, not the whole thing. The top cup does not see nearly the loads that the bottom part does.

/markp

dedhed

Common go to short stack threaded headsets are Tange. Levin, passage, etc.
Usually available in various finishes and ISO or JIS as well as crown races available separately

​​​​​​https://tangeseiki.com/jm/products/h...hreaded-1.html

Iride01 

I think you are just doing the same thing I did with bike I bought used a dozen years ago. It had a slightly different headset than what I was use too and I was simply not tightening the lock nut properly.

Took me several rides and several instances of it loosening up for me to look at it close enough and figure out what was supposed to be tightened to what.

None of the other stuff you showed in the pictures is going to be a factor for it loosening up.

cyccommute 

What you are seeing is the reason that the threadless headset was invented. mpetry912’s suggestions are good ones on how to deal with the immediate problem but threaded headsets and mountain biking have always been a problem. The top nut just won’t stay tight with all the pounding. There used to be all kinds of locking mechanisms on the headset locknut. Some were OEM and others aftermarket. Two examples are this Onza and this Odyssey headsets.

But the locking mechanism had only limited success and they have been consigned to the dust bin of history. The reason I have a headset press is the frequency that I needed to replace headsets due to just your problem from back in the day. I never really found a satisfactory solution until threadless came along.

You can still find some of the locking top nuts on Fleabay.

canopus 

Two Best things ever invented for threaded headsets, Stronglight A9 tapered roller bearings (lower race) and the GT Epoch with a spring (top race) to always keep the HS tightened. Forget the locking nuts, they were always useless. That doesn't look bad and is salvagable with the recommendations, but a nice replacement would do you just fine. I would go back in with a stronglight or a Velo Orange sealed.

Papa Tom

Wshew!!!! That would've been a "duuuuhhhh" moment! But it would have been tricky figuring out how the bearing cages fell out.

Ross200

I would definitely chase the threads with a die to give the best chance of success going forward. The damage from the keyed washer(s) s hard to correct with a thread file and will destroy any alloy cap/nut in my experience.

If your fork is 1 inch, you have better options than if 1 1/8. As MPetry12 indicates, Stronglight A9 WAS a fine option BID but the new ones are cartridge bearings, not roller. Still a great headset just not rollers. IRD Roller or Double Roller will fit your stack and have the roller bearings. IIRC, older Shimano XT/DX headsets have 1/4 in lower ball bearings which greatly increased the longevity of the install. Grade 25 bearings are a big plus.

We had great results using beeswax or Teflon pipe thread lube/sealant on the threads and Bel-Ray or StaLube Marine grease in the bearings. Legend has it Gary Fisher had all the cartridge BB bearings re-lubed with StaLube marine grease before factory install. It keeps the water away from the balls and the races better than any non-vegetable grease I've used for any application.

One overlooked issue with threaded headsets IME is Park headset wrenchs don't fit well enough to properly adjust most headsets and still damage the flats. Much coarse language results! The Stein or SnapOn Wrench Force "wrap around" wrenches are/were reasonably priced improvements.

Many chronic threaded headset problems can be traced to non-parallel head tube faces and unfaced crown seats. Have some patience and get it dialed in at the shop and the long walks on the trail become less frequent.

Iride01 

Since someone ask about the bearings, I'll go for another thing that might be a duh.

You do use two wrenches when you try to tighten the locknut don't you?

If you aren't, then you aren't doing it right. Though with some, you can get a big pair of channel locks or pipe wrench on it if you don't mind marring it up.

Dave Mayer

I spent much of the 80's punishing my bike and body riding over roots and rocks. In those days, all 'mountain bikes' had 1" threaded headsets. I faced the constant problem with headset loosening, until I finally leaned how to correctly tighten up headset threaded bits. First, you need to properly pre-load the bearings. Then, using two (big) dedicated headset wrenches, tighten the top nut and threaded top cap against each other. Note the emphasis, you need to scissor these two parts against each other - tight, without messing with the preload of the headset bearings. Simply tightening the top nut will lead to the headset loosening again, within one ride. Once I learned this, never had a problem again.

BTW: I do not see any problems with your headset parts. If your crown race is brinelled, then I suggest you re-install it rotated by a few degrees, throw away the ball retainer, and replace your current ball complement with a greater number of loose balls of the same size. That way, the higher number of loose balls cannot line up with the pits caused by (false) brinelling. I've done this operation many times; the headset will feel new again.

JohnDThompson 

Yes, you need a shorter stack headset. If the headset is shorter than what you need, you can always add spacers. But if it's taller than what you need, it won't work. Sometimes you can fudge it a bit by leaving out the toothed washer, but that only gains you about a millimeter. You lose whatever advantage the toothed washer can give in maintaining preload, and there's a risk that the locknut still won't be fully engaged. Since you're already having problems with the locknut, this will only exacerbate them.

Unca_Sam

Yes, I use two wrenches, a park tool for the cup and then an an Antique Coes wrench for the locknut. This headset has just been difficult to adjust well. I'm fairly sure it is a Tange model, with my parts bin locknut added on after the threads stripped out of the original. Even adjusting preload to ⅛ turn from binding, it was difficult to tighten the locknut down and turn the adjusting cup back to find the sweet spot between binding and knocking.

Unca_Sam

Thanks for clarifying.
The older threads with that question make it seem like a 2mm shorter stack might be ok. Frankly, I might have 2 mm slop in my measurements, but it could be either way. 🙄

Unca_Sam

This gives me more confidence in potentially continuing to use a threaded steel headset. If I punch out the cups though, they're going into box the new headset comes in, not getting reinstalled. I know that I was concerned with stripping the threads when installing the new locknut after the original failed. It's likely It wasn't tight enough, but who wants to destroy a headset on install?

ThermionicScott 

If you were formerly using a 7mm spacer and able to get the top nut on any threads at all, I can't imagine your bike really needs a short-stack HS.

I think your steerer and headset look worse to you than they really are. I'd just clean it up, repack, and ride.

Unca_Sam

The locknut is toast. I pulled the 2mm keyed washer off on the trail to try and get enough threads on so I wouldn't have to stop every half mile to a mile, but it would only get kind of tight before continuing to spin. I'll remeasure my HT and steerer to confirm i have 39 mm of stack.

ThermionicScott 

Ah, okay.

Ross200

Properly adjusting a threaded headset is a some level an acquired skill but if the cups and the crown race are not parallel, it is impossible to get adequate adjustment and keep it. The uneven wear on the bearing tracks could indicate the frame/fork would benefit greatly from facing.

Unca_Sam

Locknut reinstalled, 3mm keyed washer deleted, 5mm aluminum spacer in place.

So I reinstalled the fork and adjustable parts and measured 10.7mm lower stack plus 30.3-30.5mm for the top bits, including a 5 mm spacer. The locknut has a hair of adjustment left, and the bearings are adequately adjusted. With a 3 mm keyed washer in there, I don't have enough good threads to hold an adjustment.
The top of the locknut itself is 2mm thick confirming my earlier 39.ish mm stack measurement. The good news is that the locknut is holding after tightening against the top cup. The bad news is that I think I want a headset I know I can trust.

Unca_Sam

I'm inclined to believe that. The head tube is showing signs of rust at the top race (there's rust staining on the paint immediately under) which I'll address when the top race and bottom cup are knocked out.

I've also determined that the nylon seal on the old locknut plus the shape of the parts and seals makes this 80% of a Tange Seiki passage headset.

Unca_Sam

My LBS was pretty responsive with my request! I have a headset on order, the pressed cup and race punched and the head tube reamed and faced. An interesting development is that the crown race seat is 27mm, not 26.5. Interestingly, there is no trace of rusting that would color the paint at the head tube. I wonder if a different headset was on the bike before the one I removed that stained the paint. Another good sign is that the facing confirmed the end of the head tube were not parallel, as the mechanic found a low spot at the top of the head tube.

I, uh, also made an offer on a Suntour XC Pro headset that was accepted, so I'll have an extra either way. I'm hoping the Suntour headset has a 27mm crown race, which means no milling, plus another grease guard component on the bike.

Freshly faced head tube