Dura Ace 9000 11 speed cassette- rubish product design

[Causidicus]

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[F45]

The pictures are real. They represent anecdotal evidence. You know what that means, right?

Considering I have never even HEARD of another model cassette breaking in this fashion from ANY of the Big 3, it means a lot of DA 9000 cassettes are breaking.

[Christo]

That is possible but if ingress of lubricant is a source of any problems in a part that is supposed to be used in a lubricated environment, it's a rubbish product design.

Completely agree - just curious, have also seen people using WD40 as chain lube on top end bikes before

[KLabs]

Very late to the party here, have just seen the pics. Cogs look dirtier than I keep mine, are you using a wet lubricant? If so, could this be getting in around the rivets and causing delamination/weakness?

Hi Christo, if that was the case then I would definitely have to agree with the others that you could call this a rubish product design.

A question, could tensioning the lock ring >40nm cause an issue with CF spider compression and breakage (although the breakage is around the rivets, so probably not).
HST, CF usually does not like compression, so, could that be occurring in this instance... thanks

[mattr]

Considering I have never even HEARD of another model cassette breaking in this fashion from ANY of the Big 3, it means a lot of DA 9000 cassettes are breaking.

Despite me posting about the (fairly widespread) failures due to a poorly designed XT-9 cassette spider on this very thread?
Maybe the DA MK2 cassette should use a 5 point mount, rather than 4. (that was shimanos fix for the XT failures.)

If so, could this be getting in around the rivets and causing delamination/weakness?

It's carbon fibre reinforced plastic, rather than a cut sheet. So nothing to actually delaminate.

Actually looking at the design, could it simply be the difference between riveting a DA/titanium sprocket (quite a springy material) to the carbon reinforced plastic and riveting the Ultegra/steel sprocket (~40% higher youngs modulus) to the same/similar carrier? The springier ti sprocket moves around a lot more, allowing the plastic to fatigue? The steel one, being stiffer, spreads the load across more of the rivets. Once you start looking at tolerances on the riveting process (end load etc) you might start to see those cassettes with the poorest stack up of tolerances/thicknesses/rivet end load failing prematurely. As they move around the most.

[mattr]

And the 10 speed cassettes have failed too........

This has happened on the XT CS-771-10 11-32 as well. I've seen a few other photos of breaks in the same way around the rivet.

[743power]

Don't assume that because there is no CS-9001, that there hasn't been changes to the cassette since it's release.

[743power]

[dgran]

Come on. There are plenty of people on this forum who have good access to manufacturers and pro riders. Let's hear from people who have evidence that these cassettes have broken. I'd be totally ready to believe that Dura Ace cassettes are designed with a lot of fragility and don't last well, but I'd like real evidence, not supposition. And by evidence I mean not just casual riders with breakages that are statistically very infrequent, but pros. Who can show us all the evidence?

I'm not doubting that some of these are breaking (because stuff breaks and life, you know) but for my experience we have two bikes with DA9000 cassettes that have about a combined distance of 15k kilometers ridden with no problems. I'm about to replace one cassette and I'll probably use the Ultegra one primarily for cost saving and keep my DA cassette handy for use on a hill climb TT. I would imagine people who work at bike shops might have a better perspective if there are issues with the DA9000 cassettes.

[mythical]

The new cog carrier actually looks better and seems like it would prevent the issue of failure. I wonder about the weight penalty.

[743power]

It was under 10g difference between my old filthy cassette from my cross bike and the new updated cassette.

[clc2010]

Nice spot 743power.

Anyway, I did a bit of further digging and noticed the part numbers for the Dura Ace 9000 carbon sprocket units have been revised in the Shimano Dealer Manual. Apologies I can't post the URLs as I am a new(ish) user. I wonder if this could be indicative of a voluntary recall of some type due to the reported failures?

Shimano Dealer Manual - Exploded View - Revision Jan 2014

* 11 Y1YC98160 Sprocket Unit (19-21-23T) for 12-28T


Shimano Tech Docs - Exploded View - Revision Jul 2012

11 Y1YC98060 Sprocket Unit (19-21-23T) for 12-28T

[F45]

Considering I have never even HEARD of another model cassette breaking in this fashion from ANY of the Big 3, it means a lot of DA 9000 cassettes are breaking.

Despite me posting about the (fairly widespread) failures due to a poorly designed XT-9 cassette spider on this very thread?

Ok, you are right, but it is the same design from the same maker, so perhaps not very different.

[tomyboy2]

.....
I've got SRAM cassette on now and it works perfectly, gears change precisely... absolutely nothing wrong and all I did was put it on(myself) and adjust the gears. That's it.
I said before there are no issues now with the bike now and there wasn't before hand, bought a SRAM cassette and problem solved...

Reading all this, I am preparing for worst case scenario, when my is going to break...
If I go for SRAM X-Glide 1190 Cassette, is it better to use SRAM RED 22 Chain, rather than Dura Ace CN-9000?
Just asking for better all round fine tuning of the Di2 rear derailleur.

[petal666]

Di2 doesn't need fine tuning. It's not sram.