Crux Headset Compression Ring

Tech Tech Help
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Important tech discussion - copied from Escape Collective Discord

I’ve tried to snip out the important bits from a discussion that has been going for 18 months, as more members discovered their Crux and Aethos headsets were not happy.

Feel free to add anything you think I missed.

I have not included other members’ names in the interest of privacy.

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It is my understanding that the 2025 Crux still has the same headset design, despite Specialized apparently having alternative parts available to those that ask. This is annoying because I’d quite like to buy a new crux before they stick the cables through the headset (that’d be ironic - I bet that would fix this problem :man_facepalming:), but I’m to annoyed by this to give them more money!

Specialized Australia told our LBS that they would pay for us to replace the headset with a Wolftooth headset! We haven’t bothered because a couple of shims fixed Helen’s bike. :crossed_fingers:t3:

27-12-23:

I’ve just spent way too long trying to tighten Helen’s Crux headset that I discovered was loose this morning. I simply don’t seem to be able to tighten the top cap bolt such that the front wheel turns freely but the headset doesn’t move when I push the front wheel against the front brake or a wall. Even with some grease under the top cap bolt, soon as the bolt is finger tight (ie the torque spanner hasn’t even registered yet), the steering feels tight.

I lifted the headset cover up and the compression ring doesn’t look to me like it’s being pushed into the top bearing as much as I’d like - it seems to sit flush with the bearing before it’s started compressing into the bearing.

I wondered if there was another washer missing under the headset cover to push down on the compression ring but the drawing on Specialized dot com says what we have is correct.

I guess I’m curious if anyone (@Jase?) has had this issue before, or if anyone has suggestions.

I’ve set it up so it’s as loose as I’m comfortable, so the wheel feels tight but not terrible and the headset isn’t moving when pushing against a wall/brake.

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It seems to me that the specialized top bearing cover is just poorly designed so it doesn’t load the inner compression ring enough before the rubber seal starts dragging on the outer race or the frame. Not impressed, but at least it’s relatively easy to fix.

28-12-23:

Another member had the same problem and solved it with a Chris King Dropset 2 Headset

“I can recommend it. The steering feels so good now, super smooth”

30-12-23:

Success!

Bought 3 shims and needed 2 to get the headset to stop dragging. Stripping the hex socket in the stem cap bolt while tightening the last time was annoying but the universe had to maintain chaos.

14-5-24:

In case someone finds this thread in future, Raoul Luescher warns that the use of stainless steel shims on headset bearings can potentially damage the steerer tube! Apparently there are plastic shims available for this purpose, which I am now going to try and source…

I failed to find any plastic shims but I have made sure the metal ones in Hels crux are not touching the steerer AND I have a reminder to check regularly that it is still tight and smooth.

25-5-24:
Jase had the same problem fixed by his local bike shop who happened to have a spare split ring (of unknown origins) that was just the right size to fit his headset and provide the required clearance for the top cap.

CONCLUSION

The ultimate solution, in the absence of Specialized fixing their design, is to replace the upper headset with the WolfTooth IS42 headset, which is what Specialized Australia told our LBS to do for us. This is the link to that Wolftooth headset. Note that the Crux and Aethos ARE compatible with IS42 headsets, contrary to the note about Specialized bikes on the Wolftooth website.

Apparently the Cane Creek 40 headset is also suitable, as shown in this video by Nolan and Bike Sauce (link provided by another discord member).

Another user also provided more detail on the Wolftooth Headset choice….
Speaking from own experience (but I can ofc be wrong): The Wolftooth 7mm top cover (I think that’s also called dust cover) won’t work with the Specialized stock upper bearing. The stock bearing is just too high for the Wolftooth dust cap. The bearing that comes with the Wolftooth headset is 6,3mm high while the stock bearing is 8mm high. I tried squeezing the Wolftooth top cover over the stock bearing and that didn’t end well.

While we are already at it: The Wolftooth Performance headset (Wolf Tooth Performance IS Headsets - Integrated Standard – Wolf Tooth Components) won’t work because it comes with an IS41 bearing → Fail.

Only the Wolftooth Premium headset (Wolf Tooth Premium IS Headsets - Integrated Standard – Wolf Tooth Components) is available with an IS42 bearing which is the one you need. However, both are available with 7mm stack which makes them a pretty good replacement for the Specialized stock cap.

Long story short: This (Wolf Tooth Premium IS Headsets - Integrated Standard – Wolf Tooth Components) is the way.

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For the record, I never had any issues with my Aethos headset after nearly 20 000kms of riding it. In my view a shim or higher split-ring is sufficient of a fix without replacing the entire headset.

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Thank you ever so much for posting this it is an important thread. I recently bought my second Crux (what a brilliant bike) and the first thing I did was, taken from the original Discord thread, replace with a Wolfrace.

I do find it so odd that a company like Specialized perseveres with a design with known issues that you would think could have been changed at such a minimal cost. I do wonder what the story is there. It is such a well-known issue on a popular bike, that must generate so many warranty claims, and in the worst case with a ‘ring of death’ failure, the risk of significant damages, why have they not changed the design? Odd

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@jasedepuit‘s experience, with 2 bikes that apparently have the same headset design and one works faultlessly while the other had problems, suggests to me that this is a manufacturing tolerance issue (arguably because of a design that can’t be reliably manufactured) so maybe they still reckon the failure rate is too low to fix?? Maybe they haven’t seen it as a potential ring-of-death issue?
Having said that, the fact that Spec Aus offered us a Wolftooth headset without asking any questions is disturbing to me.

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Yeah this definitely seems like a manufacturing or design problem. In Specialized’s defence, at least they’re happy to fix the issue if there is a problem. I’ve been putting shims in any Cruz/Aethos headset that we build or service, regardless of if the issue has presented or not, and it seems to be working fine.

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Ive just clocked 15000km on my Aethos with no headset problems

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Aethos and Crux owner here. Aethos has had no issue. Spec replaced my Crux fork after a ring developed and would never be quite tight after any rough road. It just looked like the headset cap started to deteriorate after years of use.

The new fork has a shim and so far so good. I may still swap to the wolf tooth system in the future but it’s not a priority right now.

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Mine worked better after I took it apart and removed two QC stickers from the mating surface of the compression ring and headset spacers. I was quite surprised to see lightweight spacers which suggested that the headset isn’t just a minimum price product. However it still doesn’t work properly.

I experimented by replacing the stock lightweight spacers with solid ones and adding a Wolf tooth headset cap, which improved it into the acceptable category. But longer term I’d like a full wolf tooth headset when the bearings get replaced as it is simply better than the stock price point headset.

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Can anyone confirm if the 2026 models finally have a fix?

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Not me, but I’d be stoked (& pleasantly surprised) if they have.

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I’m surprised that the guy in the video seems to excuse Specialized for this problem by raising the idea that raw individual human curiosity is the best approach to fixing this headset issue rather than a company policy that stands behind its products and takes responsibility for shoddy designs and engineering. In other words, figure it out on your own and pay for the fix rather than ask the company to resolve their own problems. Never mind you spent thousands of dollars on the bike. It’s yours now so suck it up. Get over it, muster your powers of deduction, and get to it.

Specialized first told me to put spacers in my Crux. Then when that didn’t work they shipped me a 20 mm conical dust cover with a Tarmac SL6 part number on it to fix the play. And when the problem returned and I contacted the company again, I learned they had a new part in the works and they’d ship it out to me as soon as it was available. I was priority (even though they’d forgotten about me in the meanwhile, and I had to contact them). I really wish I was one of the lucky ones here who can’t report a single thing wrong with their ride. I guess the generation of us who bought these bikes were simply rolling the dice and hoping to get a good one.

As for my latest attempt at contacting the company about the issue (which has since returned), I get crickets. I’m left to assume they’re just done talking to me. Specialized keeps kicking this issue down the road and hoping it goes away. Eventually it will because a new standard will come along (like 32” wheels), people will get rid of the bike, and buy a new one. Aha! Kicking-it-down-the-road-ism works! It’s a good policy, Specialized.

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