# SRAM XG-999 durability



## rockyuphill (Nov 28, 2004)

So what's everyone's experience been for durability or reliability? 

I've got maybe 300km or there abouts on the XG-999 and a new XTR chain, and I've just started to have trouble with skipping and crunching in the 32:32 middle chainring and 32:22 granny gear combos in steep high torque climbs. The steel cogs are all fine under any torque conditions, it's just the 32T alloy cog that's a problem. Tonight when it happened I stopped and had a look at the chainline and the RD alignment and everything looks ideal, I can't see what the issue is yet. I'll have to look at it closer tomorrow and see if there's any visible problem with the teeth or alignment of the alloy cog.


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## culturesponge (Aug 15, 2007)

around 350 miles on mine (trailbike was in the shop for 7 1/2 weeks)

was alittle skittly at first and was suprised to discover the KMC x9 had worn-out much sooner than normal - 250 miles later on a new 2010 x10 chain its shifting great (touch wood)

the 190 freehub shows no sign of damage - unlike with an XTR 11-32 which appears to marr cassette register splines somewhere around the 17t or 15t cog

hows your chain?


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## rockyuphill (Nov 28, 2004)

The XTR chain wear is almost unmeasurable after 300km (3.0015" pin to pin over 6 links), I can't see anything wrong with the alloy cog, no sign of vegetation left in the cassette. I'll try it some more this weekend and see if I can track down a cause.


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## nino (Jan 13, 2004)

rockyuphill said:


> The XTR chain wear is almost unmeasurable after 300km (3.0015" pin to pin over 6 links), I can't see anything wrong with the alloy cog, no sign of vegetation left in the cassette. I'll try it some more this weekend and see if I can track down a cause.


could you take a close-up pic of the 36t cog? Maybe it shows some wear? maybe just some individual cogs most probably at the shifting ramps.


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## rockyuphill (Nov 28, 2004)

It's the 11-32T 9 speed cassette. No sign of any duress, the hard ano doesn't even have any noticeable wear. All the steel cogs are OK.

No issues in any other cog, it still doesn't quite shift the same between each of the steel cogs and from the steel to the 32T alloy cog.


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## Hardtailforever (Feb 11, 2004)

Try your low-limit screw and check your hanger alignment. There's no visible wear on the cog, and you don't seem to be wearing out your chain abnormally. Otherwise, perhaps the alloy cog is loose or slightly bent?

I'm using the 10spd version and I've had no issues with a KMC chain in more than 500km (on the chain, maybe 2/3 that on the cassette because I have both the 11-36 and 11-32 versions, mostly use the 11-36 for training and hilly/long races).


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## nino (Jan 13, 2004)

rockyuphill said:


> It's the 11-32T 9 speed cassette. No sign of any duress, the hard ano doesn't even have any noticeable wear. All the steel cogs are OK.
> 
> No issues in any other cog, it still doesn't quite shift the same between each of the steel cogs and from the steel to the 32T alloy cog.


Looking at some dents points i definitely see wear. Just at the very tip. Maybe that's just enough to make for the trouble you have...but anyway- you still might check all you can to make sure all is straight as suggested by Hardtailforever but hearing the problems you have reminds me of some aluminium cassettes which do just that: they start making funny things as soon as the teeth get worn and those first wear at the very tips where they are machined / where the shifting ramps are. That's where the dents are thinner and will wear faster.


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## culturesponge (Aug 15, 2007)

nice clear photo's

your cassette looks to be in comparatively good shape - just might just need removal and clean, then you can check the freehub

i'm with Hardtailforever, perhaps your RD has "self adjusted" or your cable is on the way out (Gore Ride-On perhaps?) or is sticking or RD movement is obstructed with muck

we have a park tool cassette brush i swipe at our cassettes with that or a stiff toothbrush every other ride before cleaning the chain, our drivetrains are seemingly wearing out at a slower rate now i'm using Rock "N" Roll Extreme or Gold (rather than white lightning)

keep us posted


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## Hand/of/Midas (Sep 19, 2007)

what camera are you using?


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## rockyuphill (Nov 28, 2004)

Fuji F30 with macro setting, and then Picasa to export with the fill lighting effect brought up.


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## Axis II (May 10, 2004)

I would say the cassette looks very good from what I can see. I have at least that many Ks on my cassette and quite a lot of racing Ks this summer with hard shifts under heavy load- I have definetly abused this cassette and it shifts as good as ever for me. The first thing I would check is the RD hanger alignment. The cassette looks clean enough to be shifting just fine. You don't need a very big hit to the RD to knock the hanger out of alignment and this could explain the issues on the32t- in my experience the shifting gets progressively worse on the rear cassette as you shift up the cassette to a larger sprocket when the hanger has been bent inboard . You prolly just need to tweak that hanger out a bit with a big crescent wrench, or such. The other place to look would be the RD. Does your RD have any "slop" in it when you grab the lower jockey pulley and push side-to-side?


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## rockyuphill (Nov 28, 2004)

Everything is straight, aligned and tight, I haven't been able to get it to happen again yet, so it still may have been some trail debris ingested in the cassette. It's odd that it only happened in the alloy cog, the same sort of torque climbing in the biggest steel cog on a paved climb there was no problem on the same rides. I can't get any inward deflection of the alloy cog in any situation on the service stand. 

I'll keep tormenting it and see if I can get it to get crunchy again.


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## Axis II (May 10, 2004)

rockyuphill said:


> Everything is straight, aligned and tight, I haven't been able to get it to happen again yet, so it still may have been some trail debris ingested in the cassette. It's odd that it only happened in the alloy cog, the same sort of torque climbing in the biggest steel cog on a paved climb there was no problem on the same rides. I can't get any inward deflection of the alloy cog in any situation on the service stand.
> 
> I'll keep tormenting it and see if I can get it to get crunchy again.


I don't know if this would make any difference, but I went with a SRAM hollow pin chain for this cassette. My thought was that if SRAM designed the cassette with a particular chain in mind it would be a SRAM. I don't have any experience with the XTR/DuraAce chain on this cassette.


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## Wildeyes (Jun 14, 2007)

Put a different cassette onto your wheel and see if you have the same issues. You need to start changing items out one at a time to see if you can at least narrow down the search as to what is causing the issues. If you go change everything at once, you won't have a clue what was causing the problem in the first place.


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## rockyuphill (Nov 28, 2004)

The problem never happened with the XTR cassette, and spare XG-999 cassettes are not to be found. So far it has not recurred with the XG-999 so whatever it was must have been transient - so likely trail debris.


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## rockyuphill (Nov 28, 2004)

*Caught in the act!*

I was out doing some long steep 32:32 climbs this morning and I caught the cassette in the act during my high torque pedal mashing climb. The chain is being pulled off the top of the big cog under high torque as it tries to straighten the chainline to the back of the cassette (about the 10 o'clock position when viewed from drive side), but only in particular places on the cog, it starts to move down to the 28T steel cog but it must hit a shift ramp and gets popped back up to the 32T cog. This is why it sounds/feels like a noisy shift under load, but the derailleur never moves a bit, it only gets derailled down toward the 28T for maybe 2-3 teeth and then it snaps back over. And it really twangs that aluminium cog when it snaps back.

I had a look at the back side of the 32T cog and there's some very shiny and damaged tips on the teeth in a couple of different spots. Not only is the anodizing gone but there's some burrs starting to form on the bike right side of the teeth. That doesn't happen if you're upshifting under load.

The hanger is straight, the derailleur is straight, and derailleur alignment is spot on, the gear runs quiet under lower load conditions, so it isn't ghost shifting (carbon hardtail).

I don't know if its just the tooth shape and shift aid profile, or if the teeth are actually deflecting under the side load when they hit that 10 o'clock position. It isn't consistent, it seems to only happen if the peak pedal masher torque happens when those teeth are coming up to that 10 o'clock position.

I'm 195 pounds and like pushing that 32:32 on climbs that other people prefer 22:32 on. I did have it happen on a section of very steep trail where I was down in the granny gear.


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## rockyuphill (Nov 28, 2004)

Some more shots of the inside of the teeth that seem to be most involved in the "events". It looks like it's shaving off the inside of one of the teeth when the chain comes back into place under load, there's a burr showing up on the inside one pointy tooth, and there's a very heavily rubbed ramp on the tooth next to it that looks like it's letting the chain pull to the outside as the burr is forming on the outside of that tooth..


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## culturesponge (Aug 15, 2007)

aha! ...perhaps SRAM should know about this 

will try a 32 + 26 cross chainy mash myself later & see if its not just your cassette that's err misbehaving


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## rockyuphill (Nov 28, 2004)

Had an interesting chat with the mechanic at the LBS and he raised an interesting point, he wondered if the cassette was intended to be used with one of the 2011 2x10 cranks like X0 or X9 with a narrower chainline than 50mm as a way of blending old and new drivetrain components. A 44-46mm chainline would greatly reduce the chain angle and the tendency to try to lift the chain off the big cog. It could be that I'm not using it for the intended application. :skep:


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## culturesponge (Aug 15, 2007)

could be. mines on a 2x9 & having no problems mashing mountains (well except for my weakling sparrow legs) 

...if your an avid grinder - i can see a great excuse to purchase a new XTR Race crankset in the near(ish) future


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## rockyuphill (Nov 28, 2004)

culturesponge said:


> could be. mines on a 2x9 & having no problems mashing mountains (well except for my weakling sparrow legs)
> 
> ...if your an avid grinder - i can see a great excuse to purchase a new XTR Race crankset in the near(ish) future


Possibly for the new carbon Element Team, the initial build will be 9 speed XTR. There's still some hills here that need a granny, some for traction control and some to prevent a brain aneurysm.


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## nino (Jan 13, 2004)

rockyuphill said:


> Had an interesting chat with the mechanic at the LBS and he raised an interesting point, he wondered if the cassette was intended to be used with one of the 2011 2x10 cranks like X0 or X9 with a narrower chainline than 50mm as a way of blending old and new drivetrain components. A 44-46mm chainline would greatly reduce the chain angle and the tendency to try to lift the chain off the big cog. It could be that I'm not using it for the intended application. :skep:


If you would have that problem on the big ring this might have been an explanation since the chain would be all crossed...but not on your 32 middle ring !

Anyway - those teeth look scary. That's won't hold up for long ... To me it looks more like the shape of the chains sideplates don't match the cassette at a certain angle. Interesting though that it's an XTR. I would have thought that it might be the DA chain which is said to have a somewhat specific profile. Anyway - not good looking.At first i would try it with a SRAM chain.


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## rockyuphill (Nov 28, 2004)

I put the XTR cassette back on this morning, 1/4 turn H/L adjust to line up the derailleur with this cassette, and off to ride the same climbs. No crunchy mis-shift noises in 32:32 combos and back to slick, quiet and fast shifts. I'm going back to the XTR. :skep: 

Maybe Mattias needs to produce a Ti 32T cog for the XG-999 cassette. That seems to be the weakest link.


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## Mattias_Hellöre (Oct 2, 2005)

Give me a used cog so I can produce one in titanium.
They should last a little longer I think.


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## rockyuphill (Nov 28, 2004)

In looking at how the press fit works, it appears that the centre sleeve is loose, so the press fit is on the pins around the circumference. There's one missing hole so that's how they're indexing the big cog. 

I'll need to see how tight an interference fit those pins are and how hard it is to remove this cog. Hopefully it isn't too difficult as I can see it would be necessary to change the alloy cog quite often.


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## rockyuphill (Nov 28, 2004)

Well that was pretty easy, a pin punch and a single tap on each one and off it came. I can also say that the alloy cog weighs 44gms. That cog is the piece that all the drive force is transferred through, and those splines on the freehub. The outer 11T cog is free to spin in it's groove.


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## rockyuphill (Nov 28, 2004)

There's definitely no where near as much tooth shaping or height variation on the back side of XTR big cog as there is on the XG-999.


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## az1jeff (Feb 5, 2007)

I know SRAM advertises that the aluminum cogs are replaceable for the XG-999 and XX cassette. Anyone price a spare aluminum 32T or XX aluminum 36T?

Jeff


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## rockyuphill (Nov 28, 2004)

I've done a search of the online for the XG-999 cog but haven't seen anything yet. The big XX cog is about $45 I believe.


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## LMN (Sep 8, 2007)

Aluminum is the wrong material for drive trains IMHO. I know guys who are running XX who block out the 36 cog for training and only use it when racing.


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## peabody (Apr 15, 2005)

LMN said:


> Aluminum is the wrong material for drive trains IMHO. I know guys who are running XX who block out the 36 cog for training and only use it when racing.


your chainrings are aluminum. i had xtr 950/960 and then switched to sram x0, and have noticed no difference in longevity. shimano is probably a little quieter and smoother
but it's not like all of a sudden i am replacing drivetrain parts every month. i ride about 7000
miles a year and have gotten good life out of all the parts i've used.


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## Circlip (Mar 29, 2004)

LMN said:


> Aluminum is the wrong material for drive trains IMHO.


No Aluminum chainrings then?


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## rockyuphill (Nov 28, 2004)

I must say that I have yet to wear out any XTR Ti cogs or XTR Ti chainring.


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## elasto (May 28, 2009)

LMN said:


> Aluminum is the wrong material for drive trains IMHO. I know guys who are running XX who block out the 36 cog for training and only use it when racing.


I think 32t is a little bit too small to be made of aluminum in the sprocket. With 36t it's starting to last longer because pedaling causes less stress for the bigger cog.


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## Mattias_Hellöre (Oct 2, 2005)

elasto said:


> I think 32t is a little bit too small to be made of aluminum in the sprocket. With 36t it's starting to last longer because pedaling causes less stress for the bigger cog.


Then the leverage from the big 36t cog down to the small splines on the cassette body is a problem too.


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## durk onion (Jun 12, 2007)

Mattias_Hellöre said:


> Then the leverage from the big 36t cog down to the small splines on the cassette body is a problem too.


That is more a function of your gearing than anything else. It doesn't matter how big the cog is as long as your gear ratio is the same.

The SRAM CNC'd cassetes, (XX and Red) are actually easier on aluminum freehub bodies in my experience. They transmit all their torque through the part of the freehub closest to the hub which has taller splines. Also the spline on the cassette is much wider compared to a single cog.


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## culturesponge (Aug 15, 2007)

+1 

damage from XTR cassettes on our precious DT 190 freehubs - but no damage at all (touch wood) from our power dome tech SRAM XG-999's (or those FRM 36t's)


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## morrisgarages (Jan 25, 2009)

Anyone else having durability problems with these cogs?


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## rockyuphill (Nov 28, 2004)

The splines on the 32T cog on the XG-999 are only 3.5mm wide x 1mm tall, so a lot less than an alloy SS cog which are typically twice that width. They're wider than a steel cog, but that's still not very much area compared to a spider type cassette.


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## rockyuphill (Nov 28, 2004)

I had a chance to talk to the SRAM tech support guys at Mont Sainte Anne during the World Champs, the interesting thing was they weren't familiar with the XG-999 cassette, they've already moved along to the 10 speed stuff and haven't had actually seen the XG-999. I explained that it was essentially a 9 speed XX cassette and proceeded to explain the issues I had. This was the first time they'd heard of any problem like the one I described.


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## DeeEight (Jan 13, 2004)

Yeah sounds like the usual crap you hear from company reps at races. Even if presented with overwhelming evidence of problems... deny, deny, and deny some more.


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## fastback67 (Apr 6, 2010)

rockyuphill said:


> This was the first time they'd heard of any problem like the one I described.


of course ;-)

at weekend i heard from another racer, that his 36t cog gets microbreaks at the area near the freehubbody. i didn't saw it, but i believe it. for race he had to use a xt :madman:


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## morrisgarages (Jan 25, 2009)

Oh no. I'm about to order a one for myself. Anyone else have issues with theirs?


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## XgreygOOse (Sep 8, 2007)

morrisgarages said:


> Oh no. I'm about to order a one for myself. Anyone else have issues with theirs?


The only issue I had was the chain skipping mostly on the larger cog. My first thought was to change my chain (was using a KMC X9SL) I had a new Wipperman chain lying around so I gave that a try. Have done over 800km of riding with no issues at all.:thumbsup: My drive train setup is DT Swiss 190 rear hub with Extralite chainrings.


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## rockyuphill (Nov 28, 2004)

XgreygOOse, was your chain fully skipping on the teeth of the large alloy cog or was it doing the same sort of one gear mis-shifting where it tries to shift off the top of the alloy cog under load, and then pops back on the big cog? 

I think I might have a new SRAM PC-99 chain laying around somewhere, maybe I'll re-assemble the cassette and try it with the SRAM chain instead of a new XTR chain.


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## facelessfools (Aug 30, 2008)

i was talking to a rep and he said that they will warranty the larger alu cogs but not offering a replacement.


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## XgreygOOse (Sep 8, 2007)

rockyuphill said:


> XgreygOOse, was your chain fully skipping on the teeth of the large alloy cog or was it doing the same sort of one gear mis-shifting where it tries to shift off the top of the alloy cog under load, and then pops back on the big cog?
> 
> I think I might have a new SRAM PC-99 chain laying around somewhere, maybe I'll re-assemble the cassette and try it with the SRAM chain instead of a new XTR chain.


If I remember it was skipping under load from second big cog to the alloy cog then back again. Also this only happened when I was on the middle ring (32t). Never skipped on the small ring (22t) and even on the large ring(44t)


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## rockyuphill (Nov 28, 2004)

That's similar to what I had happen, while running in the 32T front ring it would almost shift down to the biggest steel cog for a couple of teeth then pop back onto the big alloy cog. After the damage was happening to the cassette cog it would do it in the 22T granny as well.


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## fastback67 (Apr 6, 2010)

facelessfools said:


> i was talking to a rep and he said that they will warranty the larger alu cogs but not offering a replacement.


does that mean, that every failure, damage, wear etc. at the alu cogs is covered by warranty?
also after 3 years of using 

if the alu cogs are really an issue (future will tell us), it should be possible to get a replacement cog for private stock. 
please ask your rep: what this warranty worth is when i noticed at the evening before race, that my 36t cog doesn't work correctly?


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## mariosimas (Nov 30, 2009)

Does any of you guys uses this cassete with XTR Shadow RD + SRAM Attack ?


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## doccoraje (Jan 12, 2004)

Mattias_Hellöre said:


> Give me a used cog so I can produce one in titanium.
> They should last a little longer I think.


So, did you get a used cog to produce the Ti?
I'm asking this cause I had the same problem with the Al cog, lasted about three months, maybe 500 k.


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## Lelandjt (Feb 22, 2008)

I've always felt that middle ring/big cog is too much cross chaining, resulting in increased wear and a propensity to skip. Your story and photos prove this. Don't be lazy. Shift to the small ring and appropriate cog to get the right ratio with a straighter chain.


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## rockyuphill (Nov 28, 2004)

Not an option in a 1x9 setup.


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## doccoraje (Jan 12, 2004)

I thought the whole idea of 2x9 was to be able to use all the cogs with both chainrings.
I am using 40-26.


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## Lelandjt (Feb 22, 2008)

*Quote: "Not an option in a 1x9 setup."*

That's why I removed the largest and smallest cogs from my 1x9. I didn't trust the largest cog to not skip under hard power and the 11T would occasionally skip since any time I was using it I was flying over rough terrain and the chain was bouncing a lot (DH bike with 40T ring).


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## Lelandjt (Feb 22, 2008)

doccoraje said:


> I thought the whole idea of 2x9 was to be able to use all the cogs with both chainrings.


That was never the case with road bikes that used 2x9 for years. We'd advise customers to use the top 6 cogs with the big ring and the bottom 6 with the small. This is advice and you can feel free to ignore it but the reason for the advice is to minimize wear and skipping. The manufacturers used to say the same thing but in recent years I've heard much less talk about cross chaining. Do whatchalike but accept the consequences.


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## Mattias_Hellöre (Oct 2, 2005)

Let me know if I can help you guys with a ti cog for this cassette.


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## briscoelab (Oct 27, 2006)

My wife had an XX cassette do something similar this past summer. She was running it with a DA7900 chain, a 1x10 setup, and would get some weird skipping in a couple cogs and some premature wear on the 36T cog. 

The cassette was warranted and we switched to a sram 1091R chain.... issue solved.


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## rockyuphill (Nov 28, 2004)

Well there's a mystery solved for me. I had the cassette replaced on warranty and mounted it up with a brand new SRAM PC991 hollowpin chain and went out and climbed the nasty ugly steep standing 32:32 climbs and nary a hiccup. So it is a Shimano chain compatibility issue in my case, the XTR chain is not a good match to this cassette, but the SRAM chain works fine.

I still find that with an XTR RD/shifter it doesn't quite handle the chain the same way all the way across the cassette, the shifting between all the steel cogs doesn't feel as consistent across the whole cassette, maybe with a SRAM RD and shifter where it really slams the chain off one on to the next it would be less noticeable.


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## XgreygOOse (Sep 8, 2007)

So it was the chain then? Glad you got it sorted:thumbsup: 

I still am using mine on my Scalpel with XTR RD and Wippermann 9S1 Hollow Pin 9sp chain. IMHO, great setup and chain with zero issues for now.


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## elasto (May 28, 2009)

Anyone had any issues with this cassette and KMC X10SL chain?


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## XgreygOOse (Sep 8, 2007)

elasto said:


> Anyone had any issues with this cassette and KMC X10SL chain?


I was using this chain and found that it was skipping (while peddling uphill) on the big rings.
I switched to a Wippermann chain and no problem to date. My friend is using a SRAM PC1090R also with zero issues.


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## culturesponge (Aug 15, 2007)

only partially worn KMC x10 chains


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