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Sorry to bother you again with another weird question. On my gravelbike with Campagnolo Ekar and tune Prince CL rear hub (3 teeth, N3W freehub body), I removed the rear wheel for a routine task and made a stupid mistake re-installing it: The chain was not seated correctly on a cog but wedged inbetween the cassette and the frame. Only while tightening the thru-axle did I notice this, loosened the axle, put the chain on a cog correctly and re-tightened.

I then noticed that the freewheeling sound was different from before - less "dry", slightly "softer". I removed the wheel again and removed the cassette, but everything looked fine with the freehub body and cassette. When turning the freehub body backwards slowly, I noticed there is now one soft click shortly before the actual "hard" click. The soft click doesn't seem to engage the hub, as I can turn the hub forwards again "over" that soft click until it re-engages with the previous "hard" click. I suspect one pawl might be misaligned from tightening the thru-axle while the jammed chain caused a sideways force on the freehub body.

What should I do now? Is it possible that a pawl is misaligned? Taking the bike to an LBS will take ages (if I find any that services tune hubs at all). Should I buy the tool for removing the freehub body and check the pawls? It's not exactly cheap but I might need it sooner or later anyways for servicing the bearings. I fear that riding the bike now might damage the freehub mechanism further... I could bang my head against the wall for not paying attention while mounting the wheel!

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Generally speaking it would be very strange for a freehub mechanism to be damaged from this. Usually they're designed so that there's no place for the pawls to go and no place for the freehub body to slip to under side load. Freehub bodies receive some amount of side load just from the chain pulling on them at any angle. Pawl freehub designs usually feature stops and clearances such that the pawls themselves will be well clear of being able to interfere with anything or have their motion impeded.

I think the answer lies in what can be inferred from these pages of the manual: enter image description here enter image description here enter image description here

In their design the lateral free movement of the freehub is adjusted using micro shim type washers, and then once it's set properly the endcap is press fit (smacked on with a plastic hammer) over the axle. That's an usual way of doing it but it's a logical way of designing a hub with a minimum of threaded parts.

When your chain dropped between the small cog and the frame, that creates a gap between the right endcap and the dropout. That means that tightening the thru-axle will try to pull the right endcap towards the dropout to close that gap. In this case I believe that means it will (or could) be undoing the press fit between the permanently pressed-on left endcap on the other side of the axle. The left endcap will stop against the left bearing while the axle pulls out of it. This increases the effective length of the axle and so will increase the free play of the freehub body, which could explain your noise and sensation of different/off engagement.

enter image description here

I think the first thing you should do is check with Tune that the above is accurate and ask them what to do. Alternatively, or if they tell you bring it to a dealer and that's not practical, you could try laying the left endcap against a wood surface and smack down gently on the right endcap with a plastic hammer, as in the manual. If that doesn't work then yes you should probably get the tool and dive deeper; my next concern would be that there's some kind of shouldered stop on the axle that got damaged by the same effect of tightening the thru-axle trying to pull the axle through the freehub body. But unless they're weirdly tiny/imperceptible somehow, it doesn't look like their axles use any kind of shoulder.

enter image description here

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    Thanks for the detailed answer. I'm not sure I follow the argument that the hub axle is pulled through the hub and elongated:The left cap rests against the left dropout, so tightening the thru-axle will squeeze the hub axle inbetween the dropouts (minus the wedged chain). The right cap is not pulled to the right, but pushed by the axle, and even it it would, it would simply pull off the axle? I can feel a small bit of lateral movement of the freehub body which I suppose is intended. The clicky noise worsens when I push the freehub body towards the hub, so I think it's not a play/preload issue.
    – Erlkoenig
    Apr 3 at 19:03
  • @ErikKoenig one thing we do know from the manual is tapping down the right endcap with the left one as the contact on the other side should be safe. I think it would be reasonable to try. Apr 3 at 20:49
  • Update: I bit the bullet and bought the tool, disassembled the hub and did not find any obvious damage. After reassembly, I found that the freehub sound was back to normal. Lateral movement is exactly as it was before. So I suppose something was indeed (invisibly) misaligned and re-assembling fixed that, while play was correct. Thanks for the help!
    – Erlkoenig
    Apr 7 at 8:31

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