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Discussion Starter #1 (Edited)
Hi all, new to posting on the forum but have been reading product reviews on here for a while. I have had 2 of the new 12spd xt freehub mechanisms fail on me, and wanted to see if others have had the same experience. I built the hubs up to dt swiss xm481 rims with dt spokes as a solid set of trail/training wheels. I have had great success with shimano hubs in the past, so I saw no reason to spend more for a 350...

I'll start by saying the new design is completely different to the old system that has been around forever. Its similar to a dt, with 2 springs and separate freehub body that runs on cartidge bearings. The ratchet mechanism is self contained in the freehub body and is not user serviceable. the hub shell has cup and cone on either side. side note, the front hub is identical to the previous model.

The first failure happened within a couple weeks. I had the wheel off the bike, and it toppled over on the cassette side(hurts my soul to think about) and the cassette pulled the freehub out. At first I wasn't too concerned, thinking that they had finally copied dt swiss and made a tool free freehub. Then I realized that was not the case, as 2 small c-clips had popped out of place(one labeled DO NOT DISASSEMBLE) allowing the freehub mechanism to fall apart! I called shimano and explained what had happened. They were confused at how it fell apart, but walked me through how to reassemble it. After a few rides it started to creak like crazy(took me a couple weeks to figure out it was the hub), so I called shimano and they sent a whole new hub to my LBS under warranty.

I rebuilt the wheel with the new hub, and it worked flawlessly for 2 months. fast engagement, smooth bearings at a great price! really the goldilocks hub for 12spd IMO. Then it tried to lock on and turn into a fixie. I had just pedalled to the end of the driveway and started to coast up to a stop sign, when it made a god awful grinding sound that scared the sh*t out of me. I proceeded to lock the rear brake and slide to a stop. Upon taking it apart back at home, I found the toothed plastic spacer(think it is a tolerance thing) was completely chewed up. I think part of it must have gotten jammed in the ratchet mechanism. The two cartidge bearings in the freebody were also totally shot. I put every back together without the spacer, and while the freehub didn't lock on anymore, the horrible creaking was back.

Currently waiting on another warranty replacement, shimano maybe sending out an xtr hub. hopefully it doesn't break too.
 

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Hmmmm... subscribed

my guess with the first one is that the freehub was disassembled and reassembled incorrectly. Not saying it was you, but I don't see any other way the freehub could come off the new hub

the second one... I have no idea

The plastic spacer that got chewed up, are you referring to part #10 on this diagram?
https://si.shimano.com/pdfs/ev/EV-FH-M8110-4511.pdf

There are metal shims behind the freehub body as well
 

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What kind of disassembly did you do for the photos? I'm curious if you put the outer dust cover/c-clip thing (part 7 in the parts list) back into the hub shell? If you didn't and the photos are from after it fell apart I'd also lean to incorrect reassembly. To get the freehub off you need to remove the end cap and that c-clip to pull it apart.
 

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Discussion Starter #5
Hmmmm... subscribed

my guess with the first one is that the freehub was disassembled and reassembled incorrectly. Not saying it was you, but I don't see any other way the freehub could come off the new hub

the second one... I have no idea

The plastic spacer that got chewed up, are you referring to part #10 on this diagram?
https://si.shimano.com/pdfs/ev/EV-FH-M8110-4511.pdf

There are metal shims behind the freehub body as well
yes, item 10 on the list. It's essentially a cheap bit of plastic to take up the slop between the splines in the hubshell and the freehub body. very similar to a centerlock disc rotor interface.
 

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Discussion Starter #6
What kind of disassembly did you do for the photos? I'm curious if you put the outer dust cover/c-clip thing (part 7 in the parts list) back into the hub shell? If you didn't and the photos are from after it fell apart I'd also lean to incorrect reassembly. To get the freehub off you need to remove the end cap and that c-clip to pull it apart.
meschenbruch, I took those pictures to send to the shimano rep to show how it fell apart. It is definitely not the way to disassemble it! c clips things(pic 1 and 2 in drive gallery) came unclipped/weren't assembled correctly at the factory(I hadn't touched it), allowing the cassette to pull apart the freehub unit. In the last picture, you can see the unit reassembled as per shimano's instructions. If you look closely you can see scrapes near the c clip interface, indicating where they popped out of place under the impact of the wheel falling over.
 

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Discussion Starter #7
While I appreciate the interest in trying to solve the problem meschenbruch and millennial guy, what I am really looking for is other owners experience with this new generation of shimano hubs. Believe me, me and the head mechanic at the LBS have both spent time trying to troubleshoot these issues with guidance from shimano. I can confidently say that I know how these hubs work and go together at this point. I took the hubs apart only after they developed the issues I laid out, meaning any potential issues with assembly causing the problems were done by shimano at the factory. My main objective of this thread is to get a bigger sample size of owners of these hubs(slx, xt and xtr), to see if I somehow got two defective ones, or if is a common thing.
 

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Fair enough, not trying to imply you've done something to the hub just trying to figure out the situation. I have one of those hubs ready to lace up, just waiting on spokes, so seeing other peoples experience is also in my interest :) (and i have a fresh hub at the moment!)
 

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Discussion Starter #9
Fair enough, not trying to imply you've done something to the hub just trying to figure out the situation. I have one of those hubs ready to lace up, just waiting on spokes, so seeing other peoples experience is also in my interest :) (and i have a fresh hub at the moment!)
No worries! Based on my experience I wouldn't use the xt rear hub. Love the price and feel of them, shame they keep breaking on me. Front one is fine, same proven design as past models. Not sure if you can get a hold of the new deore hubs yet, but they looks promising. Tried and true standard pawl design by the looks of it.
 

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I read the thread. The normal operation is for it to be silent only intermittently, that's why I'm asking.
 

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I read the thread. The normal operation is for it to be silent only intermittently, that's why I'm asking.
With the plates lubed the hub is silent.

Mine was missing the spacer that keeps the plates connected. The only other not-psyclence hub i've seen doesn't go silent intermittently, didn't start making a racket at 300 miles, and had that spacer.

That's all i know, unfortunately.
 

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With the plates lubed the hub is silent.

Mine was missing the spacer that keeps the plates connected. The only other not-psyclence hub i've seen doesn't go silent intermittently, didn't start making a racket at 300 miles, and had that spacer.

That's all i know, unfortunately.
thanks! It's an interesting freehub design. Haven't been able to inspect one myself
 

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Discussion Starter #16
With the plates lubed the hub is silent.

Mine was missing the spacer that keeps the plates connected. The only other not-psyclence hub i've seen doesn't go silent intermittently, didn't start making a racket at 300 miles, and had that spacer.

That's all i know, unfortunately.
thanks for the info scott, I really appreciate it! Be good to start generating some info on these hubs for others to find. Both on the hubs I have had were silent intermittently, the faster I went, the quieter they got. I also tried lubing the internals of the first hub that fell apart, on shimano's recommendation funnily enough! It temporarily stopped the creaking, and made it go silent at lower speeds, but still loud below 10mph(ish). after a few weeks the creak came back. What model of hub was the "other" not-syclence hub you were refering to?

Was the spacer you were missing the slider(highlighted in red on your forum) on the back of the freehub unit or the toothed one that slots in between the splines? Both of mine had the slider spacer on the back in place, it gets pushed up into the slot by the spring and stays there for me. Any issues with the toothed spacer getting chewed up? Happened on both of my hubs.
 

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Following with interest. I just built a wheel with the SLX hub and put in a good month's MTB trip on it with zero issues so far. Don't know an exact number in miles.

Mine also cuts in and out of ratchet/silent. Did this right out of the box.

Hoping these don't end up being Shimano's Guide brakes because it's a fantastic hub and I really don't want to have to rebuild my wheel.
 

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Discussion Starter #18
Following with interest. I just built a wheel with the SLX hub and put in a good month's MTB trip on it with zero issues so far. Don't know an exact number in miles.

Mine also cuts in and out of ratchet/silent. Did this right out of the box.

Hoping these don't end up being Shimano's Guide brakes because it's a fantastic hub and I really don't want to have to rebuild my wheel.
good to hear!
 

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Discussion Starter #19
I wanted to give an update of what I've found on these hubs so far.

1) Me, 2 xt hub's failed- one fell apart+creaking, second creaking+ tried to lock on. see first forum post.

2)Scottzg, xt. Creaking+missing slider. see https://forums.mtbr.com/wheels-tires...n-1126885.html

3) Eicca, SLX. No issues.

4) NSMB magazine, XTR. Hub freewheeled in both directions in the cold/wet. 2 cases, the author and a commenter reported the same issue. (has great pics of internals)
https://nsmb.com/articles/teardown-shimano-xtr-m9100-hubs/
 

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subscribed & good luck fellas.
I have a new XTR and SLX f/r set that I am planning on building up but will sit tight and see how this thread plays out. They were backups for when & if my stock wheelsets failed
 
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