pharmaboy
Eats Squid
Lock ring snapped off by lbs - likely cause, not removing the spacer for a 142mm hub and the tool doesn't engage enough - anyways, unrelated to failure.
Ctguru - something over 5000km according to strava
Anyone broken an XX1, X01 cassette?
- Thread starter pharmaboy
- Start date
Ctguru - something over 5000km according to strava
link1896
Mr Greenfield
And heres me thinking it's an interference fit. Just watched ari cogs replacement how to. So is pharmaboys failure the splined fingers failing?
bikeyoulongtime
Likes Dirt
Hmm. Are you certain that snapping the lockring teeth off is unrelated? from the pic I posted, it looks like snapping the lockring teeth off is pretty much fatal. The Alu cog is press fit to the steel unit. Buut if the lockring teeth are munted like the pic you posted, there is nothing left to physically stop the steel unit from separating. Enough vibration, a little sideways shear from shifting gears, and hey presto - auto disassembly.
:/
(pic was from this blog post: http://hamfistedcyclist.blogspot.com.au/2013/12/sram-xx1-certain-amount-of-fail.html. informative!)
I hope I get 5000km from mine!
SummitFever
Eats Squid
I reckon bikeyoulongtime has nailed it. This probably means your LBS owes you a new cassette.
beejay
Likes Dirt
I've got to agree with bikeyoulongtime. I would say it's related and the LBS owes you a new cassette.
On a side note if my LBS damaged a $400+ part I'd be fuming!!!
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pharmaboy
Eats Squid
Those lock ring teeth broke off around 2000km ago ( quite possibly a lot more), and the cassette has been on and off the hub a few times since, without drama - getting torque onto the cassette to tighten has been fine. All the lock ring tabs are for, is to allow you to loosen and tighten the cassette, and that still works ( as long as you remove the 142mm spacer before attempting - or have a deep lock ring tool)
Without the lockring tabs, what stops the cassette just sliding off the hub??
Almost half of them are gone. I think there is now enough play that the steel cassette part can move enough to allow the pins to come out of the alu ring.
What sort of life do most get from their cassette? I have 6000km according to Strava; on my third chain.
Almost half of them are gone. I think there is now enough play that the steel cassette part can move enough to allow the pins to come out of the alu ring.
What sort of life do most get from their cassette? I have 6000km according to Strava; on my third chain.
hifiandmtb
Sphincter beanie
I agree with Ming. Those tabs would surely snug down the machined part against the largest cog. Thus preventing any rocking action & the disassembly of the two components.
ctguru
Likes Bikes and Dirt
nice, I'll check mine tonight
pharmaboy
Eats Squid
EDIT - NO, tightening holds the cassette on, but it doesn't pull the steel part onto the alloy part - the only solid connection is at the tabs on the 42. The cylinder sits inside the cassette and tightening it actually loads the alloy 42 with tightening
Given the creaking, I think it's a wear issue, and that the creaking was a sign the interference fit was becoming less strong over time - I'm actually surprised it's not riveted on. The actual break happened on a circa 20% grade on very grippy rock standing and pushing hard - the sort of place where if you are going to break a chain, you do.
It's lasted longer than any other previous cassette I've run, but I have been looking after it with plenty of chain renewals. I'll contact SRAM directly I think and see how I go ( it wasn't purchased locally)
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Ackland
chats d'élevage
Hey Pharma.
The cassette design is such that the alloy 42t interface with the steel one piece cogs is just to keep it aligned with the shifting pins/ramps.
Those tabs are wayyyy too flimsy to take torque.
I am in agreement that the cassette was doomed to fail the day that your ham fisted LBS ruined it and honestly I'm surprised they didn't offer replacement then and there.
The cassette design is such that the alloy 42t interface with the steel one piece cogs is just to keep it aligned with the shifting pins/ramps.
Those tabs are wayyyy too flimsy to take torque.
I am in agreement that the cassette was doomed to fail the day that your ham fisted LBS ruined it and honestly I'm surprised they didn't offer replacement then and there.
Warp
Likes Dirt
That is a rather odd design. The splines/sleeve should be one unit with the last cog or at least be more substantial, add something that does not keep the splines separated so they can transfer the torque load better. Not very friendly for maintenance in my opinion.
pharmaboy
Eats Squid
Ok, I have it in front of me, so I'll try and explain how it works ( given I'm nit sure how many people would take it apart just to check it out.
The black cylinder with the tabs that are broken, mounts inside the steel cassette - it spins freely within that cassette - ie it's just sitting there. The tabs on the steel cassette are on the outer 36t ring and mate with the 42 alloy ring. The 42 has the engagement like a normal cassette that mounts on the very inside of the XD driver. You slide the cassette onto the driver, then you tighten the free spinning cylinder which holds the 42t on the driver - it only stabilises the rest of the cassette but is not attached .
This is as surprising to me as it is to you, but having the cassette in 3 pieces in front of me, it's absolutely clear that all the torque is transferred into the 42 which then applies it to the freehub.
beejay
Likes Dirt
I agree that the load goes through the teeth of the alloy ring and it's locked on by the engagement of threads on the lock ring.
They are looking worn to me but hard to see from the photo (engagement teeth on the 42t ring).
But the lock ring tabs do engage on the 10t end of the cassette with a lip on each to engage in a channel which would help to transfer load through the cassette onto the free hub and keep everything aligned and "pulling" the steel cassette against the alloy cog. On yours it looks like the "lips of the lock ring tabs that are left have worn down?
You're probably lucky it lasted that long. Any damage on a performance part has a higher potential for failure. It sucks that the damage was caused by the LBS!!!
Hope sram can give you some better answers, and the LBS will do the right thing and sort you out
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pharmaboy
Eats Squid
I think it's a necessary design - they can't use a traditional lock ring because of the 10t - the lock ring on a normal cassette pushes the whole cassette on and tightens it, whereas because of lack of space the sleeve goes through the main part of the cassette and only tightens the rear of the cassette - in our case , an aluminium fat cog.
its a good article however that everyone with this system should read
pharmaboy
Eats Squid
42t engagement looks unworn as it sits in my hand - also no damage at all to the xd driver - looks better than any other freehub I've ever had.
As to those lips on the lockring tabs. There is some remains of those lips, and they seem to sit about 0.5 to 1 mm outside of the steel cassette, so I can't figure out if they have any function apart from making assembly easier and or making it mate with the tool properly . I don't know whether they came off in the install or whether they came off the other night when the cassette became free of all support - suspect latter, because it's a little shiny where those tabs were which is consistant with cassette spinning over freehub while trying to limp home
Edit - I see what you mean, those little tabs on the lock ring would provide some push pull support as well. Not much, they are tiny little ridges, but definitely some.
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Warp
Likes Dirt
I understand that and I'm not saying they should use a lockring. The system just doesn't work that way.
Yes, the splines could be flimsy because they do not actually see any more forces but the ones trying to separate the cassette from the fat aluminum cog, which shouldn't be that big.
The torque load I referring to was the necessary to install/remove the cassette and it is all on those small tabs and as seen, easy to damage by improper tooling/technique.
A bit more robust would be good or just simply a stronger material.
Tell you what, if I knew the proper answer I would be working for SRAM and not pounding keys from a computer, but the system is proving to be less user friendly.
They can still correct it in the next iterations.
Haakon
has an accommodating arse
Not that I'd ever let any LBS anywhere near any of my bikes, but I wonder though if my 1180 cassette is more prone to issues - its the cheaper version made of a bunch of cogs pinned together rather than machined out of one piece. Just need a couple of those pins to come loose and its all over...