# SRAM Eagle design flaw ?



## ElPablo (Sep 9, 2007)

In May I bought a Trek Fuel EX 9.9 and it has never properly shifted since I rode it out of the shop. I've gone to 6 different bike shops and no one can figure it out (hanger alignment perfect and the the derailleur has been properly set up using the red plastic SRAM b-adjustment tool - under sag). Not every time, but maybe on 6 out of 10 shifts up to the 42t or 50t sprockets, the chain rides on TOP of the sprocket teeth instead of meshing with them :

















I posted a thread about this on the Trek forums :

http://forums.mtbr.com/trek/2017-trek-fuel-ex-9-9-terrible-shifting-1051750.html#post13287214

Today the shop received a warranty cassette from SRAM but it still didn't solve the problem. so I bought a new chain and had an AHA moment when I installed it tonight.

The two largest sprockets have narrow wide type tooth profiles and the chain will not wrap around the sprockets on alternating teeth (just like on the chain ring) Narrow wide makes sense for a single chain ring but how can this possibly work on a cassette ? How can you guarantee the chain will be properly synchronized with the correct tooth profile so that narrow wide teeth are properly aligned with the alternating sized gaps of male and female chain links on EVERY shift ? And if this is supposed to work what else in my drive-train could be causing this ?

I'm not the only one experiencing this, the pinkbike Eagle review has the same problem - scroll down and look at the picture of the yeti - the chain is riding on top of the cassette teeth like mine.

https://www.pinkbike.com/news/sram-eagle-drivetrain-review-2016.html

This could also explain some other strange thing that's happening, once in a while, the chain gets out of sync with the lower derailleur pulley (it's also narrow wide) and the chain rides on top of the pulley teeth until I forcefully advance the pulley by one tooth (my mechanic started noticing this on his eagle bike too).

SRAM and all bikeshops so far have no explanation for what's happening.

Any ideas ??


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## funnyjr (Oct 31, 2009)

Perhaps your chain is too short


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## paramount3 (Jul 13, 2014)

Methinks that the Eagle is really Icarus--the gods did not intend for any cassette to span a 500% range, or to cost so many dinar. Sram has fallen to earth.


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## useport80 (Mar 6, 2008)

never had any issues with x01 eagle


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## Steel Calf (Feb 5, 2010)

interesting post but if there was a design flaw rider complaints would be all over the place on the Internets yet it isn't

I'll install GX Eagle next week and will report back should I run into the same issue


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## Loch (Apr 29, 2011)

Check for binding in the shift cable/housing, housing slightly too short etc.


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## ljsmith (Oct 26, 2007)

I have no issues with my X01 Eagle. I think your issue is you let lbs mechanics work on your bike.


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## pipots (May 18, 2017)

ljsmith said:


> I have no issues with my X01 Eagle. I think your issue is you let lbs mechanics work on your bike.


+1 on the above...I've seen a few defective part problem reported, but by reading around I would recommend trying to self tune. Eagle seems to works on a higher precision level and not all mechanics know the system. Learn the details of the tuning by doing a self tune. I'm not a mechanic myself, but I installed and tune an XX1 eagle on a 2015 Stumpy. I had a few issues that I solved by resetting the low and high limit screws, but then no issues at all, other than some retuning with the barrel every 3 or 4 trips.

While reading your post my first thought was chain too as funnyjr suggested. Also take a look at the low limit screw and the make sure yourself that the b is well set.

From what I remember, eagle drivetrain only has a narrow/wide pattern on the chainring and on one of the RD pulleys. On the cassette you have some special cut tooth that help the chain on the up/down shifting process but not an actual narrow/wide on every one.

To help on understanding, take a look at this DIY
Take a look at this thread


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## flipnidaho (Aug 10, 2004)

I've installed Eagle XO1 and XX1 on a few of my bikes without problems. Like others have said, check for binding. Also, check to make sure your shifter is pulling the cable smoothly (I saw a post about a defective Eagle shifter causing shifting problems somewhere on the interwebs).


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## alexbn921 (Mar 31, 2009)

The 42 and 50 on the eagle are narrow wide. your chain is off by 1 tooth. It will sometimes skip on the 42 and 50 if the shift ramps don't line it up right. once it's in the correct place all is good. That skip can suck if you have the power down.


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## Steel Calf (Feb 5, 2010)

alexbn921 said:


> The 42 and 50 on the eagle are narrow wide. your chain is off by 1 tooth.


I just unpacked the GX Eagle groupset and the two biggest cogs are indeed narrow wide! The chain doesn't fit on the cassette if it is "out of sync" and looks the same like the picture above!

I didn't install it yet but how's that supposed to work out? Do I have to make sure the chain is in sync every time I reinstall the rear wheel?


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## pipots (May 18, 2017)

Steel Calf said:


> I just unpacked the GX Eagle groupset and the two biggest cogs are indeed narrow wide! The chain doesn't fit on the cassette if it is "out of sync" and looks the same like the picture above!
> 
> I didn't install it yet but how's that supposed to work out? Do I have to make sure the chain is in sync every time I reinstall the rear wheel?


Really? that's a surprise...can you post a picture? are u sure is on the whole cog? I found this one on google and i don't see a clear wide-narrow pattern as in the chainring...
Cassette








Chainring


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## useport80 (Mar 6, 2008)

i'll double check my x01 eagle cassette in a few hours. i dont remember them being narrow/wide design. 50t might have special teeth, maybe to assist in easier shifting, but not necessarily require special timing or alignment with the chain. 

i haven't looked at the x01 eagle chain in awhile, but i dont remember it ever saying anything about aligning the chain or narrow/wide cassette. i watched a few youtube videos about eagle and none of the installers mention it either.

as far as i've seen/known/read, only the chainring and lower pulley have narrow/wide teeth profiles. the upper pulley is normal. i thought the cassette was normal too.

i thought the eagle cassette was just a standard 42-10t cassette with a 50t added on.


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## acedeuce802 (Jun 30, 2017)

All pictures show the cassette being equal width teeth, but they have different lengths (if length is the right way to describe it). Since chains have equal roller spacing, I wouldn't expect it to matter which tooth is in which gap in the chain, so I'm curious to hear about how this has happened to a few people.


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## useport80 (Mar 6, 2008)

yeah im also curious how this is happening. i've been on x01 eagle for about 8 months so definitely not a pro, but i've swapped chains, removed, and installed chains multiple times on my bike and never had this issue.

would the b-tension screw have anything to do with this?

those with issues, have you checked your b-tension screw?


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## alexbn921 (Mar 31, 2009)

Steel Calf said:


> I just unpacked the GX Eagle groupset and the two biggest cogs are indeed narrow wide! The chain doesn't fit on the cassette if it is "out of sync" and looks the same like the picture above!
> 
> I didn't install it yet but how's that supposed to work out? Do I have to make sure the chain is in sync every time I reinstall the rear wheel?


The shift ramps guide it onto the big cogs in sync. This happens 90% of the time. If it's out of sync it will jump 1 tooth and be in sync again. The N/W is for backpedal performance, so I doesn't jump off the 50/42.


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## mfa81 (Apr 1, 2011)

even with narrow wide profile the chain should jump cogs once aligned, worst case it skips a single tooth, it's really weird that it's jumping on top of the teeth, seems like the RD / shift are not setup correctlymaybe the rd is pushing the chain too much


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## Steel Calf (Feb 5, 2010)

alexbn921 said:


> The shift ramps guide it onto the big cogs in sync. This happens 90% of the time. If it's out of sync it will jump 1 tooth and be in sync again. The N/W is for backpedal performance, so I doesn't jump off the 50/42.


that's some good background info you've got but if it works in 90% of the time does that mean at every 10th shift the chain will be out of sync?

I'll post pictures tomorrow before installation of the whole thing but the chain doesn't fit on the cassette if it's out of sync I wouldn't believe it myself if I hadn't seen it in hand


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## alexbn921 (Mar 31, 2009)

Steel Calf said:


> that's some good background info you've got but if it works in 90% of the time does that mean at every 10th shift the chain will be out of sync?
> 
> I'll post pictures tomorrow before installation of the whole thing but the chain doesn't fit on the cassette if it's out of sync I wouldn't believe it myself if I hadn't seen it in hand


Unfortunately, yes it misses and jumps about every 10-20 shifts. I just soft pedal that shift and wait for a second to put the power down.


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## ElPablo (Sep 9, 2007)

alexbn921 said:


> The shift ramps guide it onto the big cogs in sync. This happens 90% of the time. If it's out of sync it will jump 1 tooth and be in sync again. The N/W is for backpedal performance, so I doesn't jump off the 50/42.


+1

This is exactly what's happening and probably explains why comments elsewhere describe a certain loudness or clunkiness when shifting into the lowest gears. SRAM confirmed to the shop that the chain can on occasion ride on top of the teeth but only on a bike stand. What I've noticed is that this happens also on the trail, the only difference is that when load is applied after shifting the chain skips and snaps/clanks while synching back into place. This is exacerbated when the b-screw isn't properly adjusted and why SRAM has a special tool to align it, but even when it is the problem can never truly be eliminated. Whether or not this is a design flaw can be debated, but it's certainly a compromised solution to prevent the chain from dropping when backpedaling.


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## ElPablo (Sep 9, 2007)

mfa81 said:


> even with narrow wide profile the chain should jump cogs once aligned, worst case it skips a single tooth, it's really weird that it's jumping on top of the teeth, seems like the RD / shift are not setup correctlymaybe the rd is pushing the chain too much


It actually makes sense, because the cassette is N/W the chain can't seat into alternate positions on the cassette because of the tooth profile (just like on a NW chainring) so the chain sits on top. But what's really perverse is that once you apply torque on the crank, the whole chain slips over all the cassette teeth by 1 tooth to re-synchronize itself. This is the klank you often hear when shifting into 42/50. This CANNOT be good on the drivetrain and probably explains how PeteyPhil snapped a tooth off his 50t sprocket :

Sram Eagle 1x12 - Page 5- Mtbr.com









And another :

XX1 eagle 50th broken- Mtbr.com


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## Novaterra (Jan 1, 2014)

i had the same issue, but took a look at the cassette, saw the narrow wide on the 50t and changed the chain 1 tooth, problem solved


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## garcia (Apr 10, 2008)

paramount3 said:


> Methinks that the Eagle is really Icarus--the gods did not intend for any cassette to span a 500% range, or to cost so many dinar. Sram has fallen to earth.


Thank you for this.


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## ElPablo (Sep 9, 2007)

Novaterra said:


> i had the same issue, but took a look at the cassette, saw the narrow wide on the 50t and changed the chain 1 tooth, problem solved


How does that solve the problem ?


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## pipots (May 18, 2017)

Hoping to add some facts to the discussion, I worked today for about an hour with my XX1 eagle and I can now confirm that>

- The 11th and 12th do not have a narrow wide pattern as the chainring. Though every cog has some different shaped teeth that help the chain in the shifting process. In particular the 50T cog also has special shape (link shaped) cuts on the side to help going up from 42T.

- Did about 20 to 30 random, slow and fast, up and down shifting tests and observed the chain does always sits on the same inner outer link pattern relative to a certain tooth on the 50T cog. To test this I made a mark in between two teeth on the cog and observed that the pattern always repeated. This means that on the tooth left to the mark I will always observe an outer/wide link and on the right an inner/narrow link (picture below).

- The above makes sense because by slowly pedaling while shifting from 11th and 12th you can see that the chain always goes up using the cog's side cuts to hook a wide/outer link thus the pattern is always the same.

- Never on these test I had a miss link or a skip jump as reported. Also never had an over the cog chain.

- Son IMHO, I don't think there is a design problem or anything like that. As someone mentioned, there are far more happy users than problems reported. From what I've read around, you need to concentrate first on checking any mechanical problem like a misalignment due to a bend hanger or mechanical problems on the shifter or Rear Derailleur. Some guys have reported changes in shifter under warranty to solve the problem.

- If there are no mechanical problems, you have to make sure the chain length is correct and you correctly set the b screw and high low limit screws and finally is just a matter of tuning the cable tension. To be fair though, I do have to report that whenever the systems gets a bit misadjusted you get a big mess on your pedals, but also it can be solved just with a few turns on the barrell.

Quote video> If shifting from a large cog to smaller cog is slow, turn barrel adjuster clockwise. If shifting from a small cog to a larger cog is slow, turn barrel adjuster counter clockwise.

Final Tip> Resting bike on the small cog allows for longer duration of the cable and the RD spring.


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## ElPablo (Sep 9, 2007)

pipots said:


> Hoping to add some facts to the discussion, I worked today for about an hour with my XX1 eagle and I can now confirm that>
> 
> - The 11th and 12th do not have a narrow wide pattern as the chainring. Though every cog has some different shaped teeth that help the chain in the shifting process. In particular the 50T cog also has special shape (link shaped) cuts on the side to help going up from 42T.
> 
> View attachment 1151842


The 2 largest cogs have a narrow wide type profile, it's quite obvious when you look at the tooth profile from the back of the cassette. It's more complicated than basic narrow wide, there are sections of multiple (3?) narrow teeth in a row, but narrow wide enough that the chain can only be engaged on alternate teeth - I think a few other users have shown that. Whatever we want to call it, the chain still has to be properly synchronized to shift properly. You can try it yourself, lock the rear derailleur to release tension and lift the chain up and advance it by one tooth to see what happens.

Thanks for taking the time to test your own setup. Which gears did you try ? I found it's easily reproduced on the stand by shifting between 2nd and 3rd gear repeatedly.

It's possible yours works as designed. But I'm not the only one experiencing this. 3 different mechanics have seen this happen on occasion (but didn't think anything of it at the time). And yesterday at a local bike shop we took another Eagle equipped bike from the floor on the stand and were able to reproduce it easily. After several phone calls with SRAM they told the mechanic that the chain can occasionally ride on top of the sprockets - but that it doesn't happen when riding. My experience is that it actually DOES but only for a brief moment, before the torque on the crank violently drags the chain across the sprocket by 1 tooth to re-synchronize itself (this is the big clunk you occasionally hear when shifting into those 2 gears).

Whether it's a design flaw or not is debatable, and it could be a problem with the shifter or possibly the derailleur clutch. But requiring the chain to be synchronized when shifting to 1st and 2nd gears when so many factors can prevent that from happening is asking for trouble.


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## pipots (May 18, 2017)

ElPablo said:


> The 2 largest cogs have a narrow wide type profile, it's quite obvious when you look at the tooth profile from the back of the cassette. It's more complicated than basic narrow wide, there are sections of multiple (3?) narrow teeth in a row, but narrow wide enough that the chain can only be engaged on alternate teeth - I think a few other users have shown that. Whatever we want to call it, the chain still has to be properly synchronized to shift properly. You can try it yourself, lock the rear derailleur to release tension and lift the chain up and advance it by one tooth to see what happens.


Yes you right there is a pattern, just wanted to clarify that is not the same as a n/w pattern on the chainring. That sections of "about 3" different size teeth are located near the "cuts" on the side of the 50T cog to help upshifting process. Surprisingly in my tests, all the times the chain got up correctly on the 50T cog using the "cuts" and on the the same n/w pattern (synchronized). From what I observed, that is possible because the cuts will always "grab" an outer link, so chain will enter the cog in the same places keeping the n/w pattern.
So the point is that in my case there are no "factors to prevent that" and if this is not a worldwide problem, is the way it's meant to work and there must be something particular going on in some cases.

So, to dig deeper on possible solution. We need to find out why in some cases the chain is going up desynchronized or on a different pattern, thus skipping one teeth.
Can you do do some tests and check these questions>
- How the chain is going up on the 50T cog using the cuts. Always on an outer link?
- Does the problem only happens on shifting up from 10th to 11th or 1th to 12th or also going down?
- Can you reproduce the shifting process slowly trying to check exactly what is happening on chain/cog contact on the 11th and 12 cog and if possible take a picture?

I'm going to do some testing myself and work particularly on the 3rd and 2nd shifting you reported (11th and 10th large cogs). I will also check if the w/n pattern is respected on the 11th cog.

I'm going to try and reproduce the "lift the chain up and advance it by one tooth", but again, this is not meant to happen as the chain, at least in the 50T cog, always goes up in the same n/w pattern.

Just to be sure, I forgot to tell that I did my test on a stand and we are talking about a 100% eagle setup no other vendor chains or chainrings.


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## funnyjr (Oct 31, 2009)

Another possible contributing factor to this is problem is chainstay length. The shorter chainstay length the more drastic of chainline angle. In saying that Q factor obviously plays a role. What is the recommended chain line for eagle? I don't know but perhaps try playing around w decreasing the Q factor if possible to see if makes a difference. 


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## alexbn921 (Mar 31, 2009)

I did a 12 mile loop yesterday and had 2 out of sync shifts out of around 40 total shifts. Re-synced without a problem as I was not hammering threw the shift.


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## jaydoc (Dec 24, 2014)

The quick link is also directional, so make sure it isn't upside down. Not sure if this would result in your problem, but it's a thought.


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## jeffscott (May 10, 2006)

Design Flaw or not SRAM eagle needs some tweaks.....and a second generation.


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## kosmo (Oct 27, 2004)

jeffscott said:


> Design Flaw or not SRAM eagle needs some tweaks.....and a second generation.


That's it in a nutshell.

At this pricepoint, this flaw takes me back to the days of their Avid brakes.


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## Procter (Feb 3, 2012)

I don't have Eagle but I notice OPs pics have the Sram side of the links out, and pipots pics have links that say Eagle facing out. Are the chains directional?


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## watermonkey (Jun 21, 2011)

kosmo said:


> That's it in a nutshell.
> 
> At this pricepoint, this flaw takes me back to the days of their Avid brakes.


That day is still today, just change the name from Avid to Guide.


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## ElPablo (Sep 9, 2007)

pipots said:


> So, to dig deeper on possible solution. We need to find out why in some cases the chain is going up desynchronized or on a different pattern, thus skipping one teeth.
> Can you do do some tests and check these questions>
> - How the chain is going up on the 50T cog using the cuts. Always on an outer link?
> - Does the problem only happens on shifting up from 10th to 11th or 1th to 12th or also going down?
> ...


I'm out of town for a few days but I'll put the bike on the stand over the weekend. Everything is stock, I bought the bike new from Trek.



funnyjr said:


> Another possible contributing factor to this is problem is chainstay length. The shorter chainstay length the more drastic of chainline angle. In saying that Q factor obviously plays a role. What is the recommended chain line for eagle? I don't know but perhaps try playing around w decreasing the Q factor if possible to see if makes a difference.


The chainline is "drastic" but that's just part of Eagle. The bike is stock from Trek and I don't think anything can be done to change the Q-factor.



jaydoc said:


> The quick link is also directional, so make sure it isn't upside down. Not sure if this would result in your problem, but it's a thought.


The link is directional and properly installed, chain if fine too (it's not directional)


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## Steel Calf (Feb 5, 2010)

ElPablo said:


> SRAM they told the mechanic that the chain can occasionally ride on top of the sprockets
> 
> My experience is that it actually DOES but only for a brief moment, before the torque on the crank violently drags the chain across the sprocket by 1 tooth to re-synchronize itself (this is the big clunk you occasionally hear when shifting into those 2 gears).


same here!
I noticed it to happen a few times during my first ride, it feels a bit like as if the chain was falling down onto the smaller 42T when in fact it stays on the 50T the whole time and just "synchronises"

Chain length and upper pulley clearance is set according to SRAM installation guidelines, I find it hard to believe the shifter is at fault, it's clearly the cassette design with that narrow wide profile teeth that requires the chain to be in sync

Theoretically an incorrect set b-screw could be the culprit here as a wrong distance from the upper guidance pulley to the 50T cog would initially force the chain into an unsynchronized state right after the shift. Maybe that's the reason why SRAM introduced that red plastic thing because a correct setup is more important than ever


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## kosmo (Oct 27, 2004)

Chain growth of rear sus bikes seems to be a real fire to this flame.

First, yes, I'm spoiled. OK.

Two weeks ago, I got a new Fuel EX 9.9 with Eagle, and I have what I'll call the "Eagle 1-2 Skip".

Yesterday, I got a new Procaliber 9.9 with Eagle, and took it out for a two hour ride today WITHOUT A SINGLE SKIP.

Huh?!


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## ElPablo (Sep 9, 2007)

A quick update... 

The shop said their 2 other Eagle Treks shifted fine and to bring mine back in. They changed the complete drive train, and Trek sent them a new rear chainstay. Problem still not solved.

So I pushed a little and asked to see the Eagle equipped Farley, they put it on the stand, and on the third shift, chain de-synchronized and rides on top of the cassette.

More calls to Canadian SRAM distributor, change of story "oh yeah, we've seen this a lot, SRAM has been sending customers new cassettes...". Trek hints that SRAM is aware of the problem and working on a new cassette design.

So it sounds like once again SRAM is using customers to beta test their products.


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## ElPablo (Sep 9, 2007)

After a lot of troubleshooting I think I figured out what's really happening.

When you downshift slowly, the cassette profile/ramp properly lifts the chain at the right moment and synchronizes the chain. But on quicker shifts, or direct shifts from 3-1, it's not the ramps lifting the chain but the friction from the pressure of the chain against the sprocket, so synchronization is basically hit or miss.


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## EricTheDood (Sep 22, 2017)

ElPablo said:


> After a lot of troubleshooting I think I figured out what's really happening.
> 
> When you downshift slowly, the cassette profile/ramp properly lifts the chain at the right moment and synchronizes the chain. But on quicker shifts, or direct shifts from 3-1, it's not the ramps lifting the chain but the friction from the pressure of the chain against the sprocket, so synchronization is basically hit or miss.


Well... that's annoying.

Anyone know the reason why they designed Eagle to have variable tooth spacing?

I guess I dodged a bullet when I bought a 2017 SC Hightower rather than a 2018.


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## kosmo (Oct 27, 2004)

ElPablo said:


> A quick update...
> 
> The shop said their 2 other Eagle Treks shifted fine and to bring mine back in. They changed the complete drive train, and Trek sent them a new rear chainstay. Problem still not solved.
> 
> ...


Good news! Funny, though, because SRAM USA replaced both of my RDs, but not the cassette. I was skeptical, but both shift perfectly, now.

There is clearly a bunch of small tweaking going on with the Eagle design, which is good, because I'm sure loving the range it provides!


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## alexbn921 (Mar 31, 2009)

EricTheDood said:


> Well... that's annoying.
> 
> Anyone know the reason why they designed Eagle to have variable tooth spacing?
> 
> I guess I dodged a bullet when I bought a 2017 SC Hightower rather than a 2018.


The narrow wide is so the chain doesn't derail when you backpedal. It solves one problem and causes another. It's the price you pay for having a very wide cassette.
It's not a design flaw as it was intentional and they picked the lesser of two evils.


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## Davide (Jan 29, 2004)

paramount3 said:


> Methinks that the Eagle is really Icarus--the gods did not intend for any cassette to span a 500% range, or to cost so many dinar. Sram has fallen to earth.


Not to mention how silly it is to have a 42 to 50 gap .... or 12 speed for that matter


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## alexbn921 (Mar 31, 2009)

42 to 50 is 19%
the 12 to 10 is 20%. The rest of the jumps are reasonable.


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## noapathy (Jun 24, 2008)

This is what happens when one of their "brake guys" gets transferred to a different department. :lol:


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## EricTheDood (Sep 22, 2017)

noapathy said:


> This is what happens when one of their "brake guys" gets transferred to a different department. :lol:


It's "German Engineered".






It all makes sense now. Create a solution to a problem that doesn't exist, then create a new problem.


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## Steel Calf (Feb 5, 2010)

I just talked with the Sram guys and let them check my Eagle setup, if chain length is correct b-screw adjustment is the culprit here as it determines if the chain is forced in a snyced/unsynced position.


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## Lone Rager (Dec 13, 2013)

EricTheDood said:


> It's "German Engineered"...


As was the Shamwow.


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## the mayor (Nov 18, 2004)

noapathy said:


> This is what happens when one of their "brake guys" gets transferred to a different department. :lol:


Hey....lighten up on the SRAM brake guys.
They have only been making brakes for 20+ year.....they will eventually figure it out.
PS....your post made me spit coffee on my keyboard! FTW!


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## brentos (May 19, 2006)

I have two Eagle setups, X01 on a HT, and XX1 on a FS. The X01 on the HT always has had this problem, even breaking a tooth off th 50 t cog.

The FS started great, but has gotten harder and harder to setup to avoid this problem as it has aged. 

My 11 sp X1 setup on my other hardtail has been perfect...


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## Fisty (Sep 19, 2005)

Pretty obvious from the pic. Poor chainwrap. So either the chain is out of tolerance or the cogs are.


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## Fisty (Sep 19, 2005)

The more chain wrap there is, the tighter the tolerance must be


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## ElPablo (Sep 9, 2007)

Fisty said:


> Pretty obvious from the pic. Poor chainwrap. So either the chain is out of tolerance or the cogs are.


No, the chain only meshes/synchronizes on alternating teeth; some of the teeth on the 42 and 50t sprockets are "wide".


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## phalkon30 (Jan 17, 2009)

Thought you guys would appreciate this. My eagle gx on my stache was having issues during a race. Cleaned the mud off when I got home and found this. Notice the missing teeth? Less than 10 hours on the bike..

To be fair the shop that last worked on it didn't tighten the shifter cable so it kept backing out and jumping while riding. I didn't know the root cause and should have stopped riding instead of pushing through. Doesn't speak well to durability though


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## briantortilla (Jun 18, 2009)

phalkon30 said:


> Thought you guys would appreciate this. My eagle gx on my stache was having issues during a race. Cleaned the mud off when I got home and found this. Notice the missing teeth? Less than 10 hours on the bike..
> 
> To be fair the shop that last worked on it didn't tighten the shifter cable so it kept backing out and jumping while riding. I didn't know the root cause and should have stopped riding instead of pushing through. Doesn't speak well to durability though


This can happen to any cassette if the derailleur is poorly adjusted. I have seen multiple shimano and sram cassettes missing teeth because the rider kept going even though they "heard a weird noise". Source: I'm a mechanic.


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## TiGeo (Jul 31, 2008)

First rides on my new XO1 Eagle this weekend at a 24 Hour race. Interesting that I am reading this now but I believe mine did this as well everyone once in a while. Like a small skip while it re-sync'd with the cassette when in the larger cogs.


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## Zowie (Aug 3, 2013)

briantortilla said:


> This can happen to any cassette if the derailleur is poorly adjusted. I have seen multiple shimano and sram cassettes missing teeth because the rider kept going even though they "heard a weird noise". Source: I'm a mechanic.


That's why I find cassette teeth on the trail all the time, right?

You have gone too far enough, congrats. :thumbsup:


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## Steel Calf (Feb 5, 2010)

briantortilla said:


> This can happen to any cassette if the derailleur is poorly adjusted.


Not sure if we mean the same but this happens when the rider applies full chain torque during a gear shift (the short moment the chain is on two cogs), a huge problem on ebikes these days.

Hence Sram went to 1x8 with their EX1 group and disabled the multi gear release in the shifter


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## 006_007 (Jan 12, 2004)

Steel Calf said:


> Not sure if we mean the same but this happens when the rider applies full chain torque during a gear shift (the short moment the chain is on two cogs), a huge problem on ebikes these days.
> 
> Hence Sram went to 1x8 with their EX1 group and disabled the multi gear release in the shifter


I run my e-bike singlespeed. makes it moderately challenging that way.


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## TiGeo (Jul 31, 2008)

Interesting. More testing on this issue on my new ride. In the stand, it happens occasionally in the 42 and 50. You have to give it a hard jerk to get it to slip back into sync. I have ordered the red plastic b guide to check this setting as I didn't get it from the shop when I bought my bike. Everything else seems adjusted properly.


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## Fisty (Sep 19, 2005)

Check to see where The quick link is when it does this. Chances are you will find it entering the cassette cog. Snapped one gx derailleur in two. After that snapped chain right near the quick link due to the link unlocking and causing the chain to bind and break. Running without a quick link and since has resolved all the issues.


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## GRPABT1 (Oct 22, 2015)

So SRAM released an innovative product before making sure it was reliable? You don't say....


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## TiGeo (Jul 31, 2008)

^^^I don't think this constitutes "reliable" or "not reliable", it's just a quirk. The big thing with these issues is to understand the why. Did Sram design this intentionally? Do they know about it? Are they concerned? Is it a problem? Not sure, only Sram can answer and internet speculation doesn't solve it.


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## 92gli (Sep 28, 2006)

Fisty said:


> . Running without a quick link and since has resolved all the issues.


How'd you join the chain?


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## GuitsBoy (Sep 24, 2013)

92gli said:


> How'd you join the chain?


I'm assuming he pressed a pin out, then back in to join the chain. This worked well enough on older chains 8 speed and below, but every time I attempted this on newer 9+ speed chains, the chain always breaks. Once pressed out, the pin will no longer be held with the same strength.


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## alexbn921 (Mar 31, 2009)

TiGeo said:


> Did Sram design this intentionally?
> Do they know about it?
> Is it a problem?


Yes Sram designed it intentionally to prevent backpedal problems
Yes the do.
Can be if you are shifting under high load.
I find that it is an acceptable compromise for the super wide range. I wish it didn't happened, but understand that it's better than the alternative.
Skipping has nothing to do with the quick link and you absolutely can NOT press a pin back into an eagle chain.


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## TiGeo (Jul 31, 2008)

^^^Makes sense. I agree that this has nothing to do with the power link - I have watched mine do this a bunch in the stand and it is never at the same place/at the link.


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## @[email protected] (Aug 25, 2017)

ElPablo said:


> In May I bought a Trek Fuel EX 9.9 and it has never properly shifted since I rode it out of the shop. I've gone to 6 different bike shops and no one can figure it out (hanger alignment perfect and the the derailleur has been properly set up using the red plastic SRAM b-adjustment tool - under sag). Not every time, but maybe on 6 out of 10 shifts up to the 42t or 50t sprockets, the chain rides on TOP of the sprocket teeth instead of meshing with them :
> 
> View attachment 1151559
> 
> ...


It's probably missing the chain hook because of all that crap you have covering the cassette sprockets. Is that grease?


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## TiGeo (Jul 31, 2008)

^^^Mine is brand new/spotless and does this same thing.


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## Steel Calf (Feb 5, 2010)

^^ It's the b-screw adjustment.

That's why Sram is issuing that red template, if you miss the correct setup just by a small margin the above behaviour will occur. How do I know? I can easily provoke it by changing the b-screw in either direction, a full turn already amplifies that "chain hoovering effect"

maybe some guys here should do more trial & error

you won't solve the issue by writing about it!


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## Fisty (Sep 19, 2005)

"just a quirk" - uhm no. Sram had issues from the getgo with chain and what not.


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## Fisty (Sep 19, 2005)

I will check actual chain wrap in the next few days or someone else can. Just take a fresh chain and wrap it all the way around the 2 largest cogs with the wheel off the bike. Check it with the quick link on it as well. I worked manufacturing chain and sprockets for some years. Does it wrap without issue?


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## TiGeo (Jul 31, 2008)

Got the b screw guide. It was clue and I tweaked it a touch. Removed 1 link per Sram's video on installing Eagle. Neither eliminated it.

Sent from my SM-G950U using Tapatalk


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## Fisty (Sep 19, 2005)

Fisty said:


> I will check actual chain wrap in the next few days or someone else can. Just take a fresh chain and wrap it all the way around the 2 largest cogs with the wheel off the bike. Check it with the quick link on it as well. I worked manufacturing chain and sprockets for some years. Does it wrap without issue?


Chain wrap is fine. Still no issues since running without the quick link.


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## ElPablo (Sep 9, 2007)

So, to follow up : 

SRAM replaced cassette derailleur and chain, and new cable and housing. New derailleur hanger and perfectly aligned, b adjustment tool used to set the derailleur... and...

It still shifts like crap in the two lowest gears. 

So for anyone on the fence upgrading to Eagle - DON’T !


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## briantortilla (Jun 18, 2009)

It is amazing that this thread has gotten this long. I wish I could find the SRAM video that explains the so called issue that eagle has. SRAM internationally designed the largest two cogs with a narrow wide profile. They did this in order to remedy the back pedal issue that so many people complained about. If the chain shifts out of sync on these two cogs, the chain is designed to skip forward while under load. Emphasis on under load. This is a design feature, not a design flaw, built in to prevent the back pedal issue of their 11 speed system. 

To be clear, I am not saying that this is the ideal way to design a cassette. I agree that it is not necessarily ideal. However, to all of the people complaining about their shifting, the system is designed to work this way. My eagle drivetrain shifts out of sync in the stand all the time. But in 5 months of riding every other day, it has only skipped once or twice while I was actually on the bike, and it was not a big deal. There was just a large clunk, and I went on my way. 

As a final note, eagle is not the easiest to set up. One of our most experienced shop mechanics has even had trouble with it. Hangar alignment is key, and any bendy (read cable binding) cable routing can also significantly affect shift quality.


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## TiGeo (Jul 31, 2008)

^^^Let me say that my Eagle has shifted perfectly from Day 1. I get the clunk from time to time but it's not a big deal to me. What I was looking for was whether this was ok or not - if Sram has this is the design (like it or not), then I'm good with it. I just wanted to make sure that I had followed their install which it looks like I have. I'm not sure I believe those that got rid of this (this = chain riding on top of cogs and slipping into sync) with the various methods they are saying...I just think it's how it is. I would like to see the Sram video on this as well!


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## ElPablo (Sep 9, 2007)

If this is by design, which seems likely, why is SRAM continuing to replace all my parts under warranty ?? And why is no shop mechanic besides you aware of this ?

I’d really like to see that video as well.


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## TiGeo (Jul 31, 2008)

ElPablo said:


> If this is by design, which seems likely, why is SRAM continuing to replace all my parts under warranty ?? And why is no shop mechanic besides you aware of this ?
> 
> I'd really like to see that video as well.


So Sram is replacing your Eagle bits b/c the chain rides on the cog sometimes?


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## ElPablo (Sep 9, 2007)

TiGeo said:


> So Sram is replacing your Eagle bits b/c the chain rides on the cog sometimes?


Yes...


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## TiGeo (Jul 31, 2008)

Has anyone had their stuff replaced and it sorted the problem 100%?


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## 92gli (Sep 28, 2006)

Fisty said:


> Chain wrap is fine. Still no issues since running without the quick link.


Since you didn't answer, you must have re-used a pin. I'll say a prayer for your testes.

I'm not comfortable with people suggesting this. I made the mistake back in 09 and the chain breakage resulted in me tumbling down a rocky ledge and being off the bike a month. When you press a 9, 10, 11 or 12 spd pin out the flared end is torn off and will be found around the pin on your chain tool.


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## TiGeo (Jul 31, 2008)

I have done this on a 11 speed and yes, it broke. There is a reason they give you a special pin or master link. On 7 and 8 speed stuff in the '90s it was fine to do.


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## briantortilla (Jun 18, 2009)

ElPablo said:


> If this is by design, which seems likely, why is SRAM continuing to replace all my parts under warranty ?? And why is no shop mechanic besides you aware of this ?
> 
> I'd really like to see that video as well.


For the life of me I cannot find the video. I know 100% that it did exist at some point. It may have been a product launch video at eurobike or something of that sort but it seems to be gone now. My knowledge of the design is purely based on that video.

As for why SRAM is replacing parts, I am not sure. It may just be because they have a very good warranty program. They will take basically anything from our shop no questions asked and send a replacement. From what I have read, however, most replacements have made no difference in out of sync shifts, so there is probably no point in sending in your group set. Your guess is as good as mine on this one. I do not claim to be the authority on the subject, just sharing what I know. Ill do my best to find that damn video.


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## TiGeo (Jul 31, 2008)

^^^Good info. Was it a video that actually showed this phenomenonn?


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## EricTheDood (Sep 22, 2017)

I recently picked up a Santa Cruz Nomad with X01 Eagle. So far I have two rides on it (this past Sat/Sun). 

I had it up on the stand last night and sure enough, it does the same thing.

The problem seems to fix itself in actual riding conditions. The problem is more apparent in the stand when the rear wheel spins freely.


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## TiGeo (Jul 31, 2008)

^^^Same experience here. I get a little noise or clunk when it does it riding sometimes.


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## briantortilla (Jun 18, 2009)

TiGeo said:


> ^^^Good info. Was it a video that actually showed this phenomenonn?


I cant remember if the video actually showed the phenomenon or if it was simply addressed verbally. I think I saw the video just after the initial release of eagle so it has been a while.


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## TiGeo (Jul 31, 2008)

Was it an official Sram video? Other videos show it.


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## briantortilla (Jun 18, 2009)

It was either an official SRAM video or an interview with a SRAM rep from another youtube channel. Either way, it was from the mouth of SRAM.


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## yeti rider (Dec 11, 2008)

I’ve just looked at mine on both big rings and the chain fits all the way round.


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## EricTheDood (Sep 22, 2017)

yeti rider said:


> I've just looked at mine on both big rings and the chain fits all the way round.


That's because the chain is currently synced to the narrow-wide cog.

Shift back and forth a few times and eventually it'll get out of sync.


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## TiGeo (Jul 31, 2008)

Or, just take the chain and manually advance it one cog, it won't seat anymore.


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## yeti rider (Dec 11, 2008)

EricTheDood said:


> That's because the chain is currently synced to the narrow-wide cog.
> 
> Shift back and forth a few times and eventually it'll get out of sync.


I'm going is disagree.
Put it in the bike stand, single shifts, multiple shifts throughout the whole range and it syncs on every change.


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## EricTheDood (Sep 22, 2017)

yeti rider said:


> I'm going is disagree.
> Put it in the bike stand, single shifts, multiple shifts throughout the whole range and it syncs on every change.


Interesting.

Can you confirm that your big cog is narrow-wide?

If so, the big question is how is it staying in sync? Can you snap some photos?


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## TiGeo (Jul 31, 2008)

The cassette has a profile that only allows the chain to sit in one position (not really "narrow/wide", but profiled for sure). This is not a debatable topic.


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## yeti rider (Dec 11, 2008)

Normal alignment


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## yeti rider (Dec 11, 2008)

Moved forward one tooth, had a slight gap but fully covered the cog as I slowly moved the crank forward


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## alexbn921 (Mar 31, 2009)

Yetirider. The Eagle cassettes have abbreviated narrow wide 42 and 50 sprockets. You can NOT put any power threw them if they are out of sync as they are designed to jump into the correct orientation. This is well documented. The NW is most prevalent around the shift points and can sit mostly flush on a small portion of the top 2 gears.


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## yeti rider (Dec 11, 2008)

Sorry I’m not a gearing expert, I’m just indicating I can’t see that on my bike, living in the Peak District most rides have steep climbs and the setup works perfectly for me.


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## alexbn921 (Mar 31, 2009)

Works great for me too. It will occasionally jump as others have noted and I tend to feel for the correct engagement before I hammer it. Overall it's the best drivetrain I've ridden in the last 30 years.


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## ElPablo (Sep 9, 2007)

yeti rider said:


> I'm going is disagree.
> Put it in the bike stand, single shifts, multiple shifts throughout the whole range and it syncs on every change.


I'm surprised. But looking at your pictures if you really did move the chain by 1 single tooth and there's no gap then is it possible SRAM changed the tooth profile ?

Do you have a yeti ? Here's a picture of the yeti used when pinkbike tested Eagle (with the chain un-synched) :


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## ElPablo (Sep 9, 2007)

yeti rider said:


> I'm going is disagree.
> Put it in the bike stand, single shifts, multiple shifts throughout the whole range and it syncs on every change.


It only happens in the two lowest gears - all the higher gears have normal tooth profiles and don't need to be synchronized. It's most easily reproduced with a rapid shift from 3rd (36t) to 1st (50t). When you shift slowly the ramps on the cassette properly synchronize the chain. But a rapid shift puts enough pressure and friction on the chain that it shifts before getting lifted by the ramps - and gets unsynchronized.


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## TiGeo (Jul 31, 2008)

^^^Exactly.

Sent from my SM-G950U using Tapatalk


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## yeti rider (Dec 11, 2008)

No i have a 2018 Whyte T130


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## HSracer (Jun 30, 2013)

yeti rider said:


> No i have a 2018 Whyte T130


GX cassette?


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## yeti rider (Dec 11, 2008)

yep SRAM PG-1275 Eagle, 10-50, 12 Speed
Full GX setup https://www.whyte.bike/t130s

I've just done a 15 mile ride where i climbed nearly 2000 feet with zero issues, some smooth, some bumpy, some extreme down hill, nothing but a flawless shifting performance.
Sure i heard it drop from the biggest to next cog but its a big drop.

On the first climbs i performed a multiple shift up, yanked on the brakes got off , checked the chain alignment and every time it was on all the teeth, i checked the tightness of the top length of chain and it was always as expected. If the chain was jumping forward a tooth i would expect some slackness as it not also going to jump on the crankset.

Real world i'm not seeing anything that suggests I have an issue. Sorry but thats my feedback.

So is this?
Non real world testing?
Badly set up installation?
Poor bike design?
Poor frame build and alignment?

Has this actually been raised directly with SRAM support and what was the feedback?
I can't believe after thousands of hours of testing and multiple manufactures using the system that such an easily replicated design flaw as you suggest has not been identified and called out.

I've read and watched bike review while choosing the Whyte and no one called this out?


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## alexbn921 (Mar 31, 2009)

Thread closed. It's all in our heads.


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## ElPablo (Sep 9, 2007)

That's the frustrating question I'm trying to answer, and one that SRAM is skirting around. One SRAM tech says oh yeah it can happen, while another is warrantying the entire drivetrain, and yet another alluded to a future redesign of the cassette. Apparently there was a video about it, but now no one can find it. Every bike shop that has Eagle has noticed it but most don't know why it happens. And many bike shops don't even have the plastic SRAM tool to properly align the b-tension. Out of 15 or so eagle bikes I've now tested I haven't seen one NOT do it.

When it happens on the trail the chain slides/snaps forward into place with a clang you surely must have experienced (again only shifting from 3 to 2/1 - the rest of the range is perfect). Briantortilla says it is by design, which is plausible, but it would be nice for SRAM to officially confirm this so that we can stop trying to fix a non-existent problem.

Are you 100% certain that the chain meshes correctly on the two largest sprockets in all positions ? Unless SRAM recently redesigned the tooth profile it's impossible for the chain to mesh on alternate teeth.



yeti rider said:


> yep SRAM PG-1275 Eagle, 10-50, 12 Speed
> Full GX setup https://www.whyte.bike/t130s
> 
> I've just done a 15 mile ride where i climbed nearly 2000 feet with zero issues, some smooth, some bumpy, some extreme down hill, nothing but a flawless shifting performance.
> ...


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## yeti rider (Dec 11, 2008)

I’ve done about 100 miles on the Whyte and I’ve not had any issues at all, maybe I’m just lucky but it’s working perfectly for me.

Maybe after it’s got a few more hill miles on it and lots of my riding is up hill.

I’ve also started leaving the bike in the smallest cog which I saw on the SRAM site as it indicated it puts less strain on the cable and mech.

I’ll advise if anything changes.


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## Rick Draper (Dec 1, 2009)

Got Eagle on 2 bikes and have 4 cassettes on different wheels. I can make them both go out of sync on the stand but on the trail I cannot make it happen.


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## TiGeo (Jul 31, 2008)

Update. Mech at the LBS that I bought my bike from called and talked to Sram. Like others are saying, they acknowledge that this happens from time to time in the stand/not under power but shouldn't happen on the trail. The clunk I get from time to time is just the chain finding it's place on the narrow/wide profile of the 42 and the 50. They want to hear if it causes issues etc. as this is a somewhat new system. No conspiracy's. I am happy with my setup and can handle a noise once in a while.


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## yeti rider (Dec 11, 2008)

I wonder how it would feel if the higher cogs were actually closer?
By how much would it affect the climbing ability?


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## JKDjEdi (Nov 22, 2015)

Installed my Eagle GX groupset and on the first ride the 50 cog breaks a tooth mid ride. WTF. I did the B check under sag as suggested and made sure the high low settings were spot on the day before. New chain, everything new and at mile 8 the tooth breaks. Took it to the shop and one guy says might not be warrantied because I installed it... Yeah right. The head mechanic took a look and said that these guys were built to take some damage and was puzzled by the broken tooth. He's gonna call SRAM Monday for a replacement. If it breaks again I will freak and go back to 11 speed.









Sent from my VS995 using Tapatalk


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## WHALENARD (Feb 21, 2010)

New to eagle and have experienced the exact phenomena the OP describes. Under power the chain will ride up on top of the 42t cog and pop/slam down in when it seats. My immediate thought was that the jockey wheel was not perfectly lining up with the 42t cog and the chain was ever so slightly getting caught on the shift ramps of the 50t and thus riding up on top of the cog. The interesting part here is that it shifted perfectly suggesting cable tension was good. Went ahead and backed the barrel adjuster off more than I would have thought and it stopped doing it solving my problem. Seems eagle shifts well over quite a wide range of cable tension which is new to me.


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## GuitsBoy (Sep 24, 2013)

I wouldnt sweat it too much. Ive had plenty of SRAM stuff warrantied through online shops. They may go back and forth with your a couple of times via email, but once they get the feel that you know what youre doing, they warranty without much trouble. At least thats been my experience with them.


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## WHALENARD (Feb 21, 2010)

JKDjEdi said:


> Installed my Eagle GX groupset and on the first ride the 50 cog breaks a tooth mid ride. WTF. I did the B check under sag as suggested and made sure the high low settings were spot on the day before. New chain, everything new and at mile 8 the tooth breaks. Took it to the shop and one guy says might not be warrantied because I installed it... Yeah right. The head mechanic took a look and said that these guys were built to take some damage and was puzzled by the broken tooth. He's gonna call SRAM Monday for a replacement. If it breaks again I will freak and go back to 11 speed.
> 
> 
> 
> ...


I've done that with 11 speed. If you notice the broken tooth is right at the top of a shift ramp. Try not to shift under a lot of load. Also it's good technique to hold the shifter lever firm when shifting into the top cog until the chain is all the way on and wrapped the cog before releasing it. Chain line could be a factor as well. Sucks but I'd bet the farm Sram will warranty that lickity split. I've had good luck and fast service simply calling them directly as well.


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## JKDjEdi (Nov 22, 2015)

WHALENARD said:


> I've done that with 11 speed. If you notice the broken tooth is right at the top of a shift ramp. Try not to shift under a lot of load. Also it's good technique to hold the shifter lever firm when shifting into the top cog until the chain is all the way on and wrapped the cog before releasing it. Chain line could be a factor as well. Sucks but I'd bet the farm Sram will warranty that lickity split. I've had good luck and fast service simply calling them directly as well.


 Thanks, the lbs guy who questioned my installment started to creep in my head a little, I mean how hard is it to screw in a Cogset, right? And I have descent tools (from Jensonusa.com)! I was going up a killer climb today 1mile up a 13.5% grade. but with the prior 11 sram cogset I had, never even winced on that climb and it's 2 years old! I'll try that hold lever till the chain seats technique, and maybe just a fluke thing?


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## JKDjEdi (Nov 22, 2015)

WHALENARD said:


> New to eagle and have experienced the exact phenomena the OP describes. Under power the chain will ride up on top of the 42t cog and pop/slam down in when it seats. My immediate thought was that the jockey wheel was not perfectly lining up with the 42t cog and the chain was ever so slightly getting caught on the shift ramps of the 50t and thus riding up on top of the cog. The interesting part here is that it shifted perfectly suggesting cable tension was good. Went ahead and backed the barrel adjuster off more than I would have thought and it stopped doing it solving my problem. Seems eagle shifts well over quite a wide range of cable tension which is new to me.


I was just messing with my cable tension just now to try and create this phenomenon and yup, the chain will ride on top of the gears if not aligned right. when the reviews said these Eagles were finicky they were not kidding! Hopefully after the cable breaks in (stretching) this goes away. Not a fan right now. Is this happening with just the GX cogset or all the way up the line to the pricey ones too?


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## scooterman (Aug 10, 2004)

I didn't read every post here, but there is no way to fix what is being described. The 50T is a narrow wide cog. Under load when actually riding the bike, it should shift just fine. I have eagle on my bike and it seems to work, I had one issue when i was going up a hill (not even sure you can call it a hill more like rock walls) i could barely turn the pedals at like 20 rpm, I shifted to the 50T and the chain popped off. So for some of you low RPM "oh crap i need to shift" shifting may be causing some issues. 

In a repair stand with no load you have a 50/50 chance of the chain riding up like that. Also if you loose your chain riding, do not try to put it back on the 50T shift and put it back on another gear. 

To an above post it's all the eagle not just GX. One thing I've noticed about GX eagle is it's very sensitive to hanger alignment. XX XO far less so.


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## JKDjEdi (Nov 22, 2015)

scooterman said:


> I didn't read every post here, but there is no way to fix what is being described. The 50T is a narrow wide cog. Under load when actually riding the bike, it should shift just fine. I have eagle on my bike and it seems to work, I had one issue when i was going up a hill (not even sure you can call it a hill more like rock walls) i could barely turn the pedals at like 20 rpm, I shifted to the 50T and the chain popped off. So for some of you low RPM "oh crap i need to shift" shifting may be causing some issues.
> 
> In a repair stand with no load you have a 50/50 chance of the chain riding up like that. Also if you loose your chain riding, do not try to put it back on the 50T shift and put it back on another gear.
> 
> To an above post it's all the eagle not just GX. One thing I've noticed about GX eagle is it's very sensitive to hanger alignment. XX XO far less so.


The derailer adjustment is super finicky, your gonna have to really spend some time adjusting this thing to almost precise specs, especially the B adjustment. Good luck!!

Sent from my VS995 using Tapatalk


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## JKDjEdi (Nov 22, 2015)

Add to my comment above... My brother n law got the GX Eagle and he had the lbs install it, turns out they didn't fine tune it and he was having all kinds of shifting issues, riding the 50 and it would want to jump down one under pressure, and we're talking any little pressure, so we adjusted the tension on the cable from the shifter. We tightened the tension. We found out that the high limit screw needed a little adjustment as well and then checked the B tension with the little red plastic tool SRAM ships with all their derailers, and yup... That was way off too! You need to adjust the B screw limit under your normal sag from rear suspension. After all those settings dialed In we could not get that to shift bad or skip drop whatever no matter how hard we tried. 

Sent from my VS995 using Tapatalk


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## Mad.Mtb (Aug 4, 2014)

Thought I'd bump this thread with my experience. I just built up a SC 5010 for the Mrs. using the GX eagle. I had this issue with the 2nd cog failing to sync. I tried a number of adjustments to solve the issue and a few things helped lessen it, but nothing made it disappear completely. I also found it more pronounced when shifting up the block 2-3 gears and into the 2nd cog. In this scenario, the chain would ride on the top teeth of the 2nd cog for half a crank or so, then fall into place. If I came down from the largest cog, it would miss syncing about every 10-15 links.

I decided to trouble shoot the issue by putting my rear wheel and its own cassette on her bike. Same thing occurred. This helped determine it had to be the derailleur, so I returned it to the online dealer and got the XO1 model, mostly because it had go on sale. When I installed it there was zero syncing issues and it has run flawlessly since. 

I had installed the GX eagle on my own bike about six months prior. It was not an easy DT to install for someone of my skill level, but I followed Sram's online video for installation and tweaked it until I got it working perfectly. I have had zero issue with it in 700+ miles of riding.


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## TiGeo (Jul 31, 2008)

Mad Reptilian said:


> Thought I'd bump this thread with my experience. I just built up a SC 5010 for the Mrs. using the GX eagle. I had this issue with the 2nd cog failing to sync. I tried a number of adjustments to solve the issue and a few things helped lessen it, but nothing made it disappear completely. I also found it more pronounced when shifting up the block 2-3 gears and into the 2nd cog. In this scenario, the chain would ride on the top teeth of the 2nd cog for half a crank or so, then fall into place. If I came down from the largest cog, it would miss syncing about every 10-15 links.
> 
> I decided to trouble shoot the issue by putting my rear wheel and its own cassette on her bike. Same thing occurred. This helped determine it had to be the derailleur, so I returned it to the online dealer and got the XO1 model, mostly because it had go on sale. When I installed it there was zero syncing issues and it has run flawlessly since.
> 
> I had installed the GX eagle on my own bike about six months prior. It was not an easy DT to install for someone of my skill level, but I followed Sram's online video for installation and tweaked it until I got it working perfectly. I have had zero issue with it in 700+ miles of riding.


I honestly believe all Eagle drivetrains do this - there is no way around it. The 42/50 are narrow-wide and at some point the chain won't climb into those gears sync'd corretly. I have XO1 and it does it. My buddies have GX and they both do it. Sram will tell you they know about it. It's more pronounced when not under load in a stand as when you are riding it if it climbs up out of sync it will quickly re-sync sometimes seemlessly sometimes with a small noise.


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## supergadfly (Sep 11, 2018)

The same flaw exists on the "new" SRAM ex1 8 speed drivetrain. New since 2016.

I was able to get the skip to happen less frequently by using a caliper to set the derailluer gap.

The plastic detailluer gage is unique to the 8 speed ex1 and difficult to find.


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## TiGeo (Jul 31, 2008)

supergadfly said:


> The same flaw exists on the "new" SRAM ex1 8 speed drivetrain. New since 2016.
> 
> I was able to get the skip to happen less frequently by using a caliper to set the derailluer gap.
> 
> The plastic detailluer gage is unique to the 8 speed ex1 and difficult to find.


Yes, the b-screw adj seems to be the key here and I have the red plastic gauge to set mine. It only happens once in a while and I just don't notice it really.


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## phalkon30 (Jan 17, 2009)

I actually caught my eagle on a hard tail doing this yesterday in the stand. Never noticed it riding, and it synced up fine after a shift out of the big 2 and back


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## Ole (Feb 22, 2004)

I have Eagle on several bikes, and experience this on and off. But on my XC race bike, I have a 12s cassette from Ingrid Components, with Eagle derailleur. It shifts much more smoothly in the lighter gears compared to Eagle. It doesn't have narrow wide.

Who back pedals enough in the lightest gears to prioritize it over good shifting? Maybe it's time to bring out the Dremel and sand those teeth flat...


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## mezastel (Jun 15, 2018)

I got Eagle on my fatbike and sadly am experiencing all these troubles too. Sometimes the chain just goes over the larger chain and just falls off


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## mtnbkrmike (Mar 26, 2015)

Just stumbled across this thread. I have had issues with my X01 Eagle from day 1 and thought I was imagining things. I don’t even go near the bottom 2 gears anymore. After years of riding a SRAM 11 speed with nothing but silky smoothness, all of a sudden my shifts down there are loud and clunky and a bit of a buzzkill. So I just avoid it altogether. 

I’m building a hard tail. Think I may stick with the original plan of trying Shimano this time around, after not having had anything Shimano for well over 5 years. Either that, or go back to the tried and true SRAM 11 speed.


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## TiGeo (Jul 31, 2008)

It's an adjustment issue...it's finicky...my XO1 is smooth as silk..took some time with the b screw to get it sorted.

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## TiGeo (Jul 31, 2008)

mezastel said:


> I got Eagle on my fatbike and sadly am experiencing all these troubles too. Sometimes the chain just goes over the larger chain and just falls off


2 words...limit screw.

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## JKDjEdi (Nov 22, 2015)

Same here, after playing, learning, and fine tuning the b screw, lower and upper limit screws, and just aligning the upper cog to the 50 cog, kinda feel like an expert now...everything works smoothly. And if its a new setup expect it to need some more fine tuning after 50 miles...this set up is super sensitive to cable stretch. 

Sent from my VS995 using Tapatalk


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## mtnbkrmike (Mar 26, 2015)

Unrelated, but I bent the **** out of my derailleur hanger too. I haven't done that for maybe a decade. And now I find out this is a common occurrence with all the Eagle rear d's. 

My 11 speed SRAM was flawless. I seem to be having nothing but trouble with my 12 speed X01 Eagle, and it's still early stages with it. 

Anyway, I will fiddle around with it along the lines you suggested and see if I can fine tune it. Love the range, but not in love with it overall. Not yet anyway.

I think it must be karma for all the times I was all over my daughter for horrible shifts under load. Now she just stares at me when we are riding along and all of a sudden you can hear my drivetrain go clUnK-gRind-clUnK-CluNk, echoing through the trees. All I need are some of my old Avid brakes and I would have a SRAM symphony of horrible noises going on.


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## fedfox (Aug 22, 2017)

Hi everyone,

I have a GX eagle on my Nomad 2018 and it worth gloriously the first 100 miles or so, but recently the chain is sliding inside the cage on the top pulley wheel. I had the chain replace with an XX1 and a new cage replace problem persist, taken the bike to different bike shops and none seem to solve the issue. This is happening in high gears mostly the last three, I have read that the GX derailleur is super sensitive and not as good as the XO1 OR XX1 that that is a reason why a lot of bikes with the GX have the XO1 derailleur. It is worth getting an XO1 or XX1 derailleur? I am starting to get really frustrated any help will be appreciated. Thank you in advance


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## Steel Calf (Feb 5, 2010)

fedfox said:


> the chain is sliding inside the cage on the top pulley wheel


I read it trice but still not sure what you mean


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## Fisty (Sep 19, 2005)

He means it comes of the upper pulley wheel and lodges in between the wheel pulley and the cage. Happened twice to my bud. Ripped off and destroyed derailleur the first time and the second time the same happened and destroyed the rear wheel when it went into the spokes. I bet the engineer behind this clusterf$#! is lOK king for a job.


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## fedfox (Aug 22, 2017)

Like fisty said "He means it comes of the upper pulley wheel and lodges in between the wheel pulley and the cage. Happened twice to my bud. Ripped off and destroyed derailleur the first time and the second time the same happened and destroyed the rear wheel when it went into the spokes. I bet the engineer behind this clusterf$#! is lOK king for a job."

It gets loose upper pulley and wheel cage is now happening in the two to three highest gears, and once this week i dropped the chain shifting under power two the highest gears. Any help will be appreciated. Thank you


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## fedfox (Aug 22, 2017)

UPDATE:

I crashed and bended the GX derailleur, i replaced it with an XO1 and boy what a difference. It is crispier, smoother, and it does not have all that side to side movement the GX as, and it shifts great under power. Over all a better built, now i wonder it the GX derailler was damaged and my LBS did not catch it; any how after more the 40 miles and over 5000 ft of climbing i only notice one issue once when the chain was going into the 50t, over all so much better.


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## TiGeo (Jul 31, 2008)

^^^there's a reason why it costs more

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## jarango (Apr 2, 2009)

alexbn921 said:


> The narrow wide is so the chain doesn't derail when you backpedal. It solves one problem and causes another. It's the price you pay for having a very wide cassette.
> It's not a design flaw as it was intentional and they picked the lesser of two evils.


Shifting bad is lesser of two evils compared to back-pedaling drop? Give me a break !!


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## jarango (Apr 2, 2009)

TiGeo said:


> ^^^I don't think this constitutes "reliable" or "not reliable", it's just a quirk. The big thing with these issues is to understand the why. Did Sram design this intentionally? Do they know about it? Are they concerned? Is it a problem? Not sure, only Sram can answer and internet speculation doesn't solve it.


A quirk is an understatement. At this price point one would expect excellent shifting. This makes for a very unpleasant ride.


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## jarango (Apr 2, 2009)

Steel Calf said:


> ^^ It's the b-screw adjustment.
> 
> That's why Sram is issuing that red template, if you miss the correct setup just by a small margin the above behaviour will occur. How do I know? I can easily provoke it by changing the b-screw in either direction, a full turn already amplifies that "chain hoovering effect"
> 
> ...


It happens to me even when the b-screw is right on spot according to the tool.


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## jarango (Apr 2, 2009)

What a great relief to know that the crappy shifting is "designed to work that way".


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## sturge (Feb 22, 2009)

Seems GX12 is a love/hate setup for many. I've had good results setting it up per SRAM videos and it always shifts great. BUT...my issue is RELIABILITY and HIGH COST OF REPLACEMENT. The unusually long cage for the Eagle 12spd sits very low and it's a debris magnet compared to any other bike I've had in 25 years of riding. Got this bike in January and I've pulled in sticks multiple times which has caused the following in separate incidents:
-twisted and trashed one derailleur ($110 a whack on-line)
-sheared a hanger
-pulled cage into spokes 3-4 different times but I caught it and averted carnage
-current derailleur cage is somewhat out of alignment but I've been able to keep it working so far
-have Park derailleur hanger alignment tool which helps

The last thing I'm going to do is go for a similarly designed but more expensive 12 spd SRAM X01 or XX1 setup. A derailleur is $275 and cassette is $375!

I've already scoped out my 'plan' to ditch the 12 speed for 11 spd:
-Switch to 11spd Shimano XT RD-8008 der ($65), and XT M8000 shifter ($38)
-11spd SRAM XG-1150 Eagle cassette ($100...Shimano won't work due to XD drive)
-Swap out Eagle 34T chainring for 30T ($15...SRAM Eagle steel Direct Mount)

I can do all the above for about $250 and be back to having a 'normal' derailleur setup and stop the debris sucking madness.


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## D Bone (Jul 20, 2014)

I've had an X1 11 speed shifter & RD along with a GX all steel 10-42 cassette for years without issue...... not one.

Now I'm on a brand new Eagle GX setup on my 2019 Chameleon and I can't believe that the 1st and/or 2nd (50/42) gear out of sync CLUNK every 2 out of 10 shifts is acceptable to anyone.

Yes the B-Gap is exactly on the money, as is the limit screws and indexing as well.... It shifts great up and down, except for when it goes out of sync on the 42 and/or 50, which is 20% of the time.

Super disappointed with Eagle, and what's the over/under when SRAM comes out with a "new and improved" version 2.0 cassette with the narrow/wide teeth removed...... I'll set it at 10 months. 

Looking at a GX or XT 11 speed setup to replace this overrated 'high tech' drive train.


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## TwoTone (Jul 5, 2011)

D Bone said:


> I've had an X1 11 speed shifter & RD along with a GX all steel 10-42 cassette for years without issue...... not one.
> 
> Now I'm on a brand new Eagle GX setup on my 2019 Chameleon and I can't believe that the 1st and/or 2nd (50/42) gear out of sync CLUNK every 2 out of 10 shifts is acceptable to anyone.
> 
> ...


Hey they beat Shimano - that's all that matters.


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## mtnbkrmike (Mar 26, 2015)

My 12 speed XO drivetrain is significantly worse than my old XX1 11 speed drivetrain. SIGNIFICANTLY worse. For all the reasons cited above. Shitty shifting in the lowest gears (I have to do a half pedal stroke to make sure things are good to go before I start torquing), and derailleur hanger bent to ****. I feel as though I have to be so careful with that drivetrain. It feels incredibly delicate to me. I check after every ride to see if I have broken any teeth in my cassette.

In hindsight, my 11 speed was flawless. This current SRAM drivetrain is a buzz kill. 

I haven't had one single piece of Shimano gear on a bike since about 2012. Going back to Shimano with my new hardtail. It will be interesting to compare them once I have the hardtail up and rolling (c'mon Fox...WTF???).


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## glader60 (May 4, 2006)

I built up a new full suspension 29er with all X01 drivetrain. Aligned the derailleur hanger to the wheel, which was off in both directions. Followed the Sram provided instructions, paying close attention to chain length with suspension where rear axle is farthest from the bottom bracket, b-screw set at proper sag with red gauge and L/H stop screws set exactly per instructions.

Checked my work on the stand, shifts were fast and crisp, but I notice the chain riding up on 1st and 2nd teeth every now and then. Checked and Rechecked all my setup per the instructions and everything was set perfectly. Was thinking I had something off on my setup so I searched for the issue, found this post, read it and decided to just ride the bike. I road on some mild trails on my property and shifted up and down 1-2-3-4, 4-3-2-1 over and over and could never repeat the chain riding on top of 1st or 2nd. So, on the stand it sucked, on the trail it's perfect. I've since put many 100 trail miles on the bike and maybe had it ride up on 1st/2nd once or twice, I think.

Bottom line, as least for me, set it up exactly like the instructions and it works great. Super crisp fast shifts. Really happy with this set up and I'm coming from a 9 speed XT 3X drivetrain which was super reliable.


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## GrandRoyal369 (Aug 18, 2008)

So, this is all a huge relief knowing it’s not just myself having issues with 1st and 2nd gear on my GX while on a work stand. For the most part, the bike shifts well on the trail. I will say 1st gear is ridiculously huge, to the point where I rarely use it because it’s almost hard to keep balance while riding uphill at such a slow speed. 

Somebody mentioned the RD being a stick magnet. Very true... several occasions where sticks are wedged between lower cage tensioner pulley. 

But the main point I wanted to mention: I ride a Kona Honzo... it has REALLY short chain stays (2” shorter compared to my Framed Carbon Alaskan fat bike). 
On the stand while in 1st gear, my chain will sometimes drop to 2nd gear. The RD and cable tension are spot on because if I adjust, I lose my range of shifting on 12th gear. When standing at the rear of the bike and observing the chainline while in 1st gear, it becomes super obvious the angle at which the chain has to function.

So my point?

While Eagle is super trick and overall a great concept, I feel as though it’s not well suited for bikes with a SHORT CHAINSTAY due to the extreme chain line angle. But, I rarely use 1st gear, so in all honesty, I’m pleased with the shifting, for the most part. 

On a side note, with my upper and lower limit adjustments and cable set correctly, while riding in 6th gear, I get a faint rubbing/clicking sound... the chain is slightly rubbing 5th gear. When I ever so slightly adjust cable tension to remove this condition, I then loose my ability to reach 1st gear. When I readjust cable tension to obtain 1st gear, I have chain rub between 5th and 6th. My only guess is my RD is slightly tweaked. Any thoughts?


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## jamuel (Dec 16, 2018)

Not to beat a dead horse but Sick Biker has a SRAM RD tuning video 



 and at 11:02 where he's testing multiple gear down shifting to the 50T cog you can easily see the chain out of sync. He then shifts up and then shifts back down and this time it's in sync. At which point he exclaims, "This is great!"


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## JKDjEdi (Nov 22, 2015)

Hey guys I have theory on the whole rear derailer problems...is it really the derailed? What if this whole time it was just the cheap shifter not locking in its position. It doesnt have sharp teeth to hold its position. So as it loosens up...well, poor shifting ensues.


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## D Bone (Jul 20, 2014)

jamuel said:


> Not to beat a dead horse but Sick Bike has a SRAM RD tuning video
> 
> 
> 
> and at 11:02 where he's testing multiple gear down shifting to the 50T cog you can easily see the chain out of something sync. He then shifts up and then shifts back down and this time it's in sync.


SRAM tried to 'fix' the problem of the chain dropping off of the two largest rear cogs when back pedaling by making them a narrow wide design...... Kind of like having a mice problem, and letting snakes loose in your house to 'fix' the problem.

SRAM wanted to sell lots of their shiny new tech, so they catered to the lowest common denominator by adding a 12th gear..... after all, more is better.

But doing so made the rear cassette so wide and the chainline so bad, that they had to try and put a band aid on the problem rather than take a good hard look at their overall design.

Had they have made Eagle a 10-48 tooth 11-speed cassette with 12 speed cog spacing, then they wouldn't have had to purposely design a flaw into their drivetrain to address the main inherent flaw of the cassette being just too damn wide.

The rider would still have more than enough range, without having to triple and quadruple tap all of their shifting like we have to do now on Eagle, and the chainline wouldn't be a complete disaster like it is now.

...... Hey SRAM, Shimano and Box - Build a better drivetrain, not one with the most gears.


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## TwoTone (Jul 5, 2011)

D Bone said:


> SRAM tried to 'fix' the problem of the chain dropping off of the two largest rear cogs when back pedaling by making them a narrow wide design...... Kind of like having a mice problem, and letting snakes loose in your house to 'fix' the problem.
> 
> SRAM wanted to sell lots of their shiny new tech, so they catered to the lowest common denominator by adding a 12th gear..... after all, more is better.
> 
> ...


But isn't more important that they beat Shimano instead of doing some engineering like Shimano did?


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## D Bone (Jul 20, 2014)

TwoTone said:


> But isn't more important that they beat Shimano instead of doing some engineering like Shimano did?


If OneUp would devote 1 solid year to building a drivetrain, they would rule the MTB world.


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## Velodonata (May 12, 2018)

D Bone said:


> If OneUp would devote 1 solid year to building a drivetrain, they would rule the MTB world.


LOL. They would be so out of business.


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## MagicShite (Oct 20, 2015)

D Bone said:


> SRAM tried to 'fix' the problem of the chain dropping off of the two largest rear cogs when back pedaling by making them a narrow wide design...... Kind of like having a mice problem, and letting snakes loose in your house to 'fix' the problem.
> 
> SRAM wanted to sell lots of their shiny new tech, so they catered to the lowest common denominator by adding a 12th gear..... after all, more is better.
> 
> ...


working in a niche industry,

Hype and "features" are what sells...not actual useful, practical, solid, robust devices.

I have developed a contempt for my "other" hobby since working in that industry.


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## clintj (Nov 17, 2018)

I just ran across this thread, and I want to say thank you to everyone. Now I know I'm not imagining things when it looks like my chain is surfing the top of the 42 and 50t cogs in the repair stand. I've spent a fair bit of time looking mine over trying to see if something is bent and trying different adjustments.

Faith in my sanity restored!

Sent from my Pixel 2 using Tapatalk


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## goldsbar (Dec 2, 2004)

For the record, this is still happening. My brand new (well, now 150 miles) 2020 Top Fuel does exactly what's described. I'm going to check the alignment and B screw to see if that helps.


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## mtnbkrmike (Mar 26, 2015)

goldsbar said:


> For the record, this is still happening. My brand new (well, now 150 miles) 2020 Top Fuel does exactly what's described. I'm going to check the alignment and B screw to see if that helps.


My XO Eagle drivetrain is an utter piece of ****. Complete buzz kill. I would say at least 50% of the time, any downshifts into 3rd, 2nd, but especially 1st, I have to literally do at least a a full crank rotation before I can lay any power to the pedals, waiting for the chain to finally engage.

It blows my mind more people do not have this problem or if they do, that it does not seem to bother them.

My 11 speed XT drivetrain on my Honzo DESTROYS my 12 speed XO Eagle on my Druid. I am in the process of yet another build (my winter commuter Unit - SLX 11 speed), and I just had the drivetrain replaced on my C-Dale CX, and am about to get it replaced on my fixed gear (thank God that one will be inexpensive). As soon as I have all that done, I am replacing my Eagle XO with a 12 speed XT or XTR drivetrain on my Druid. Bye Bye SRAM.


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## TwoTone (Jul 5, 2011)

goldsbar said:


> For the record, this is still happening. My brand new (well, now 150 miles) 2020 Top Fuel does exactly what's described. I'm going to check the alignment and B screw to see if that helps.


Of course it's still happening, what did you expect? The 50t and 42t are still wide narrow cogs. There are no fairies in the RD watching to time the shifts.


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## mtnbkrmike (Mar 26, 2015)

TwoTone said:


> Of course it's still happening, what did you expect? The 50t and 42t are still wide narrow cogs. There are no fairies in the RD watching to time the shifts.


Assuming for the moment that this is a widespread issue, then why in God's name does nobody else care? It drives me insane to have such absolute **** hanging off my otherwise nice bike. It truly is a buzz kill for me to have to wait for my chain to engage whenever I go near my easiest gears (which I have to do, given my local terrain).


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## RS VR6 (Mar 29, 2007)

I've had a GX Eagle bike since May of this year...and just installed a X01 Eagle. The GX bike shifts just fine. I had no idea that the chain gets out of sync until I put it on the bike stand months later. It's not something that can be felt on the bike. The bike was pre built and derailleur already adjusted...I didn't have to do anything. Still no issues shifting.

The X01 I installed myself and it was super finicky to set up. The chain kept riding on top of the 42 and 50 cogs. On the bike...it would slip in both gears. I had to re adjust the b tension a couple times. It took a while to adjust. I think I have it so that it no longer skips in the 42 and 50.

I let out the air in the shock...then used two long zip ties and tied them to the wheel and seat tube. I kept tightening the zip ties till the shock was at 30% sag. Then used the B tool to adjust the B gap.


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## TwoTone (Jul 5, 2011)

RS VR6 said:


> I've had a GX Eagle bike since May of this year...and just installed a X01 Eagle. The GX bike shifts just fine. I had no idea that the chain gets out of sync until I put it on the bike stand months later. It's not something that can be felt on the bike. The bike was pre built and derailleur already adjusted...I didn't have to do anything. Still no issues shifting.
> 
> The X01 I installed myself and it was super finicky to set up. The chain kept riding on top of the 42 and 50 cogs. On the bike...it would slip in both gears. I had to re adjust the b tension a couple times. It took a while to adjust. I think I have it so that it no longer skips in the 42 and 50.
> 
> I let out the air in the shock...then used two long zip ties and tied them to the wheel and seat tube. I kept tightening the zip ties till the shock was at 30% sag. Then used the B tool to adjust the B gap.


Everyone knows there is nothing syncing the chain and teeth on the cogs, so while you may have it so that you don't feel the skips, it is happening.

No different than flipping a coin. Yea it's possible you get heads 1000 times in a row but highly unlikely.


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## fmendes (Jun 25, 2016)

goldsbar said:


> For the record, this is still happening. My brand new (well, now 150 miles) 2020 Top Fuel does exactly what's described. I'm going to check the alignment and B screw to see if that helps.


As the second post above said, try adding another pair of links to the chain.


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## PlanB (Nov 22, 2007)

I’ve had six months on an XX1 setup and I can’t say I’ve noticed this issue. I ride quite a bit and did two gnarly stage races in rough conditions with no issues at all. If this unsynching is happening, I’m not noticing it. I can occasionally get it to happen in the work stand, but can’t feel it while riding. 

I find the shifting to be much more precise than the XTR9000 it replaced. And of course the range is great. I’ll be on XT 12s soon. It’ll be interesting to make that comparison.


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## minimusprime (May 26, 2009)

My x01 and gx eagle drive trains have both done this with improper btension, chain length, incorrect limit adjustment and incorrect index adjustment. In fact, my x01 drivetrain was doing this the other day after changing wheelsets that require a different limit adjsutment and after I spent some time adjusting out b-tension and high limit, it was completely gone. For reference, I have personally run 4 different (brand new) eagle drivetrains and have around 3500 miles on eagle. 

I've setup eagle on just shy of 20 bikes at this point... I haven't seen a single one where I couldn't get this adjusted out of the drivetrain with proper setup. I find it's best to tune an eagle drivetrain like I true a wheel. Ie, do everything in cycles re-checking adjustments after I have made corrections to others.


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## RS VR6 (Mar 29, 2007)

TwoTone said:


> Everyone knows there is nothing syncing the chain and teeth on the cogs, so while you may have it so that you don't feel the skips, it is happening.
> 
> No different than flipping a coin. Yea it's possible you get heads 1000 times in a row but highly unlikely.


I never denied it happening. It's just that I've never noticed it when riding the bike. I had no idea the chain was not syncing until I put the bike on the stand. This is on the V3 LS.

I came across this thread trying to figure out how to adjust my X01 Eagle I recently installed on my Following.


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## Outhouse (Jul 26, 2019)

Just installed my GX eagle 12s, took 20 minutes and works as it is supposed to. Perfect.


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## TwoTone (Jul 5, 2011)

minimusprime said:


> I've setup eagle on just shy of 20 bikes at this point... I haven't seen a single one where I couldn't get this adjusted out of the drivetrain with proper setup. I find it's best to tune an eagle drivetrain like I true a wheel. Ie, do everything in cycles re-checking adjustments after I have made corrections to others.


I call bullshit. It's a mechanical device and there is nothing to sync the chain and teeth. There is no way to 'tune' it out.


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## alexbn921 (Mar 31, 2009)

TwoTone said:


> I call bullshit. It's a mechanical device and there is nothing to sync the chain and teeth. There is no way to 'tune' it out.


There is a mechanical device to assist the shifting only on the correct link. The shift ramps are designed to keep everything synced during the shifting action. Slight variations in setup and wear on the cassette can affect these shift ramps.

My bike has this problem dropping from the 50 to the 42. It sucks and I wish it wasn't an issue. It's still a good drivetrain, but now that shimano has 12 speeds, I would pick them 100% of the time.


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## TwoTone (Jul 5, 2011)

alexbn921 said:


> There is a mechanical device to assist the shifting only on the correct link. The shift ramps are designed to keep everything synced during the shifting action. Slight variations in setup and wear on the cassette can affect these shift ramps.
> 
> My bike has this problem dropping from the 50 to the 42. It sucks and I wish it wasn't an issue. It's still a good drivetrain, but now that shimano has 12 speeds, I would pick them 100% of the time.


I know there are ramps, but we've all been around this long enough to know ramps aren't 100% even on a perfectly tuned set up.


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## Andrew8404 (Nov 20, 2011)

I call BS on everything. Have had multiple 12 speed GX and X01 with no issues compared to Shimano. There are very slight differences between the two. All shift and perform like there supposed to unless you have something installed correctly.


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## mtnbkrmike (Mar 26, 2015)

You guys have given me hope. I will give it one last shot to try to cure my XO drivetrain of all that ails it. If it's not cured, then it's XTR for me. This is a case where I definitely hope to be wrong. The Eagle drivetrains are not inexpensive. It bothers me to have to replace it.


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## Velodonata (May 12, 2018)

TwoTone said:


> I know there are ramps, but we've all been around this long enough to know ramps aren't 100% even on a perfectly tuned set up.


Yeah, it just seems that Eagle is more sensitive to proper setup than previous systems, and if you don't get it dialed the chain is less likely to ride the ramps up to the next bigger cog. If it isn't following the ramp path, there's a 50/50 chance it goes out of sync. One of the things that makes AXS seem to shift smoother than mechanical Eagle is the controlled rate that the derailleur moves the chain allows it to be picked up more reliably than by a random thumb mash.


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## RS VR6 (Mar 29, 2007)

So far I'm having issues with the 42T. When under load...the chain will skip into the 42T. On the stand and just pedaling around...it shifts with no issues. Introduce some load...and it'll skip and clunk into the 42T. I went to the bike shop and they checked that my hager is straight. Checked the chain length too..and that is good. They also tried adjusting it to no avail. Soon as I pedal up that hill behind my house...it'll clunk into the 42T. Am I not adjusting something right? The GX shifts just fine...but the X01...not so much.


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## TwoTone (Jul 5, 2011)

Andrew8404 said:


> I call BS on everything. Have had multiple 12 speed GX and X01 with no issues compared to Shimano. There are very slight differences between the two. All shift and perform like there supposed to unless you have something installed correctly.
> 
> Sent from my iPhone using Tapatalk


Go ahead and call BS all you want. We'll make this simple: Fact- the two largest cogs are wide narrow. Fact- there is nothing other than ramps to sync the shift. Fact- ramps aren't 100%.
So what can you present as fact that an Eagle system can be tuned so that the chain 100% of the time never rides up on the cassette out of sync?
I hope you have something better than I never felt on my rides.


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## Andrew8404 (Nov 20, 2011)

TwoTone said:


> Go ahead and call BS all you want. We'll make this simple: Fact- the two largest cogs are wide narrow. Fact- there is nothing other than ramps to sync the shift. Fact- ramps aren't 100%.
> So what can you present as fact that an Eagle system can be tuned so that the chain 100% of the time never rides up on the cassette out of sync?
> I hope you have something better than I never felt on my rides.


Ha ha what a clown. Fact is all systems need to be tuned properly or they won't shift properly.

Sent from my iPhone using Tapatalk


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## TwoTone (Jul 5, 2011)

Andrew8404 said:


> Ha ha what a clown. Fact is all systems need to be tuned properly or they won't shift properly.
> 
> Sent from my iPhone using Tapatalk


Eagle is the only one with wide narrow cogs and we're specifically talking about the chain riding up on those, so basically you got nothing.


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## Andrew8404 (Nov 20, 2011)

TwoTone said:


> Eagle is the only one with wide narrow cogs and we're specifically talking about the chain riding up on those, so basically you got nothing.


Let's see two years on eagle no chain riding up. It's called not installed correctly.

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## RS VR6 (Mar 29, 2007)

TwoTone said:


> Eagle is the only one with wide narrow cogs and we're specifically talking about the chain riding up on those, so basically you got nothing.


That's what seems to be the problem. It's almost like the teeth are too thick and the chain can't settle on to the teeth. I was looking at how the teeth picks up the chain and the teeth will pick up the inner edge of the inner link...then instead of meshing with the chain...it makes the chain ride up on the teeth.

I think if you had a longer chain stay and less of an extreme angle with the chain...it might not happen as much.


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## TwoTone (Jul 5, 2011)

Andrew8404 said:


> Let's see two years on eagle no chain riding up. It's called not installed correctly.
> 
> Sent from my iPhone using Tapatalk


You think the chain isn't riding up, willing to bet your bike it isn't?


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## Andrew8404 (Nov 20, 2011)

Sure I’ll take a picture when I get home. I’ll be expecting your bike. 


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## Velodonata (May 12, 2018)

Andrew8404 said:


> Sure I'll take a picture when I get home. I'll be expecting your bike.


You should start packing yours up, it's basically impossible that it's never ridden up on those cogs. It may not happen very often, and it may not be noticeable to you, but expecting the chain to follow the shift gates perfectly every shift is wishful thinking, and when it doesn't there's a decent chance it rides up before settling even if it's only for a brief moment.


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## TwoTone (Jul 5, 2011)

What is a picture going to prove?

Video 20- 30 minutes of shifting in and out of the top two cogs.


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## Andrew8404 (Nov 20, 2011)

TwoTone said:


> What is a picture going to prove?
> 
> Video 20- 30 minutes of shifting in and out of the top two cogs.


Ha ha oh no it may occasionally ride up on the cog in a 20-30 minute video. It's not like I've ever noticed it in two years. I was going to send a picture showing it's not riding on the cog which is what you say it's going to do. You put no parameters on it. Who cares once in 30mins?? Really?? Get over being a fanboy of a certain manufacture for no reason. There all good these days.

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## mtnbkrmike (Mar 26, 2015)

Andrew8404 said:


> Ha ha oh no it may occasionally ride up on the cog in a 20-30 minute video. It's not like I've ever noticed it in two years. I was going to send a picture showing it's not riding on the cog which is what you say it's going to do. You put no parameters on it. Who cares once in 30mins?? Really?? Get over being a fanboy of a certain manufacture for no reason. There all good these days.
> 
> Sent from my iPhone using Tapatalk


Clown? Fanboy? Agreed that those are words that come to mind when reading through this thread, but not for TwoTone.


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## Andrew8404 (Nov 20, 2011)

mtnbkrmike said:


> Clown? Fanboy? Agreed that those are words that come to mind when reading through this thread, but not for TwoTone.


Ya I suppose I'm a clown/fanboy for liking Shimano and SRAM stuff equally.

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## Velodonata (May 12, 2018)

Andrew8404 said:


> Ya I suppose I'm a clown/fanboy for liking Shimano and SRAM stuff equally.


No, not at all. It's for the crap quality of your posts.


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## Andrew8404 (Nov 20, 2011)

Velodonata said:


> No, not at all. It's for the crap quality of your posts.


For saying Shimano and SRAM drivetrains are great?? Ya, crappy posts.

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## TwoTone (Jul 5, 2011)

Andrew8404 said:


> Ha ha oh no it may occasionally ride up on the cog in a 20-30 minute video. It's not like I've ever noticed it in two years. I was going to send a picture showing it's not riding on the cog which is what you say it's going to do. You put no parameters on it. Who cares once in 30mins?? Really?? Get over being a fanboy of a certain manufacture for no reason. There all good these days.
> 
> Sent from my iPhone using Tapatalk


So wait, you went from never happens to it might some times- hmmm

Funny you call me the fanboy yet it's you that can't seem to separate fact from feelings. I admit I don't care for the Sram products I've had, but I'm simply pointing out an issue with the Eagle drive train keeps throwing people like you into hysterics.

I responded to a post saying it's still happening as though there is a way to fix- there isn't. You come on and call me a clown for pointing out why it happens and that it impossible for it to never happen.

We all see who the clown/fanboy is.


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## Andrew8404 (Nov 20, 2011)

TwoTone said:


> So wait, you went from never happens to it might some times- hmmm
> 
> Funny you call me the fanboy yet it's you that can't seem to separate fact from feelings. I admit I don't care for the Sram products I've had, but I'm simply pointing out an issue with the Eagle drive train keeps throwing people like you into hysterics.
> 
> ...


I didn't understand your hysterics because you made it seem like it always rides on top of the cogs. That's why I couldn't believe you wanted a thirty minute video because that means it may only happen occasionally. I'm not denying there's issues because everyone has issues with any product. There's no perfect product! But after two years on two GX systems and one X01 I haven't had any issues that your speaking of. My point is simply that both Shimano and SRAM make great drivetrain and you can't go wrong with either one. You obviously couldn't handle that comment and got all pissed off. I hate SRAM brakes in general and love Shimano even though I've ridden some SRAM brakes that were great. So either A) you have a defective product or B) something isn't set up right. But to state that it's happens to every eagle system is hilarious and ignorant.


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## Idawho (May 8, 2020)

I had this same issue on my GX Eagle. Top two rings skip shifting periodically with a clunk. Had 2 mechanics look at it with no luck. Thought for sure that it was something I'd just have to live with. It was time for a new chain. I contacted Sram who gave me some advice. Make sure your chain is not too long and get your B-screw dialed.

Turns out my old chain was 2 links too long according to the Eagle manual. Upgraded to x01 chain at the proper length, perfect b screw adjustment and I believe my issue is solved. Two long rides without it happening when it would normally happen around 6 times per ride. It is at least significantly reduced. 

I don't understand how shortening a chain would solve this, but it worked for me. Excellent customer service from SRAM as well.


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## EPR (Jun 7, 2020)

*Check the tooth alingment on the cog too*

I had this problem of the chain clicking in the 42T cog on my Eagle X01 drivetrain and found this thread. After checking everything listed throughout this thread for an hour+ (chain length, b-tension, etc., etc., etc.) I decided to shift into the 42 and slowly pedal backward, watching every chain link engage the teeth.

I noticed that the chain was clicking by getting hung up and then falling into place on one tooth on the cog. I took a small flathead screwdriver to that tooth and gently but firmly bent it out just a bit. Problem solved.

The chain still occasionally "rides" on top of the teeth on the 42T and 50T cogs, but this happens on both of my Eagle bikes (X01 and XX1). This isn't noticeable when riding though (but the clicking in the 42T cog was very noticeable).

I hope this helps someone by saving time and trouble!


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## PiroChu (Apr 8, 2004)

*Sharing my scenarios & observations*

With this very issue at hand, I found this helpful thread on the topic (& finally finished reading all comments, too). I've also noted the premise that people on this particular thread are discussing this topic after meticulously adjusted all that can be mechanically tinkered with (H/L, B-, links, etc) already.

Here're my scenarios & observations to share...

Setup (12spd):

Cassette: SRAM XG-1275 Eagle (10T-50T)
Crankset/Chainring: SRAM/Truvativ Descendent Carbon (30T)
Derailleur/Shifter: SRAM X01 Eagle
Chain: SRAM GX Eagle (116 links)
Chainstay Length: 435mm
(I listed my chainstay length above, because some folks also talked about the extreme chain angle with shorter chainstays.)

Symptoms:

With Eagle/12spd setup above, I have the same dreaded 'ka-clunk!' slip issue when shifting down from 42T to 50T while riding on trails. It happens pretty consistently throughout a ride. It doesn't happen on any other cogs, to/from up or down. It doesn't happen when on bike stand or flat parking lot (ie. not under load/torque).

#1 - My first observation seems to align with the general consensus that this system is "very sensitive" (ie. requiring more meticulous installation/adjustments). 
My chain consistently requires replacing at 500 miles of usage (at "0.5" on Park Tool CC-3.2). When I slap on a brand-new chain, this symptom seems to go away initially, until the symptom starts to creep up again after about 300 miles of usage.
So, perhaps the system is "very sensitive" not only to derailleur installation/adjustments but also to chain wear. As such, I was starting to contemplate whether to routinely replace my chain at a rather wasteful interval, until...

#2 - My second observation sounds like "snake oil" (because I can't explain it), but I'll list it anyway, in case anyone is desperate as I am to try anything after all the meticulous adjustments.
I generally keep my drivetrain pretty clean & lubed for every ride, using Tri-Flow in (mostly-)dry NorCal for decades. However, for the very last ride on my last chain (last ride of the chain at 480 miles, before hitting 500 miles at "0.5" on CC-3.2 to be replaced), I lubed my chain with WPL Dry Chain Lube, which I had just purchased (for a different reason, not related to this issue). I rode my usual route (same route, condition, pace) with WPL lube, and the dreaded 'ka-clunk' slip didn't even happen once! That's quite a significant difference (zero vs numerous slips per ride), and I'm completely puzzled on this. So, perhaps something is helping with the sensitivity.
When my brand-new chain that I just slapped on hits 300 miles or so (which is when I expect the 'ka-clunk' slip symptom to resurface), I'll observe with WPL lube again, and report back...

Thanks for reading. Stay safe out there, everyone!
- PiroChu


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## Asmodeus2112 (Jan 4, 2008)

I occasionally get the chain on my older eagle 50T cassette riding out of sync and riding up. Anyone know if the new Eagle cassettes are the same? NW on the biggest two cogs?


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## phalkon30 (Jan 17, 2009)

Asmodeus2112 said:


> I occasionally get the chain on my older eagle 50T cassette riding out of sync and riding up. Anyone know if the new Eagle cassettes are the same? NW on the biggest two cogs?


Probably not the cassettes fault if it's riding up in the 2 big gears. Check your chain length (at correct sag), b screw adjustment using the sram tool, and hanger alignment. If it's just the top gear have you adjusted your limit screw? Chain stretch within standard?

My point is a properly set up eagle should never have this issue regardless of hardware version. Annoying clicks, yes, but skipping gears no

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## Asmodeus2112 (Jan 4, 2008)

phalkon30 said:


> Probably not the cassettes fault if it's riding up in the 2 big gears. Check your chain length (at correct sag), b screw adjustment using the sram tool, and hanger alignment. If it's just the top gear have you adjusted your limit screw? Chain stretch within standard?
> 
> My point is a properly set up eagle should never have this issue regardless of hardware version. Annoying clicks, yes, but skipping gears no
> 
> Sent from my Pixel 5 using Tapatalk


Thanks for the reply, but I have it set up correctly. I completely understand how this is supposed to work, but the reality is that this design is not flawless.

My question is, have there been any changes to the newer eagle cassettes?


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## yourrealdad (May 17, 2012)

Glad I found this thread. I have been having this issue of the chain popping or cracking while riding in the lowest 2 gears. I figured maybe it was a bent hanger or something, etc, etc.

I have messed with everything and today finally noticed that the chain is riding high on the 42/50. I can physically move the chain one link up and it then rides fine, but all it takes is a hard shift and a little skip of the chain over the correct tooth and we are back again to riding high.

I also assume that this is causing increased wear on the drivetrain?

So since it doesn't sound like there is a fix to this from SRAM (they make it really hard to like their stuff), will a Garburuk cassette solve this problem?


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## SleepeRst (Nov 30, 2011)

yourrealdad said:


> Glad I found this thread. I have been having this issue of the chain popping or cracking while riding in the lowest 2 gears. I figured maybe it was a bent hanger or something, etc, etc.
> 
> I have messed with everything and today finally noticed that the chain is riding high on the 42/50. I can physically move the chain one link up and it then rides fine, but all it takes is a hard shift and a little skip of the chain over the correct tooth and we are back again to riding high.
> 
> ...


I found the 12spd Garburuk cassette to shift worse than the stock eagle cassette (gx), could just never get it quite right, although it is light!


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## LewisQC (Jul 3, 2013)

Just thought I'd share my experience if it can help someone... I've been having this problem on my Salsa Blackborow fatbike. It began last season while shifting to the 50T of my eagle drivetrain (NX cassette/ derailler, XO chain, GX shifter). I don't remember having this problem the season before. I just stripped my bike to the frame to change BB and headset so I thought everything would be fine with new cable, etc. But no matter what I tried (fiddling with limit screws, B screw, checking chain lenght again) I couldn't set the derailler properly. Chain rollers were on cassette tooth for maybe 1 on 2 shift.

Then I remembered that last season I went from riding the bike in shortest chainstay (440mm) to the longest position (457mm) to gain traction while climbing in soft condition and reduce drifting of the back wheel on fast/twisty descents. So I tried to move the axle toward the shortest position (now sits at 448mm) and without touching anything else, it now shift perfectly... So to me it probably explain why some people will have this trouble and others won't. Just a matter of few mm depending on frame/setup. I have Eagle on my Ripmo (GX derailler/cassette, XO chain/shifter) and never experience this...

Honestly I was about to give up and get a SLX/XT combo but now I'll run this setup a bit more and save some $$$


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## Jayem (Jul 16, 2005)

Also, my worn pulley manifested itself as an out-of-sync situation in the easiest gear yesterday. I got a stick through the derailleur which forced the derailleur into a spoke and after a bunch of messing around and resetting limits I was able to get it working decently for the rest of the ride, but the pulley would go out of sync in the easiest gear if I pushed hard. It was just worn and this event was enough to push it over the edge. I had a new pulley set at home and everything is great again, but this could be one of the issues on a worn setup too.


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## LewisQC (Jul 3, 2013)

Jayem said:


> but this could be one of the issues on a worn setup too.


I'm sure it's a possibility. But I ride my fat only in winter, so not a lot of mileage (probably between 5 to 700km) and since I don't ride dirt, component tend to last for a while... Here's a picture of my derailler/cassette before I changed my chainstay lenght... They look almost like new


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## FJSnoozer (Mar 3, 2015)

LewisQC said:


> I'm sure it's a possibility. But I ride my fat only in winter, so not a lot of mileage (probably between 5 to 700km) and since I don't ride dirt, component tend to last for a while... Here's a picture of my derailler/cassette before I changed my chainstay lenght... They look almost like new
> View attachment 1956036


I am not a professional mechanic, but I set up bikes for many racers and handle their maintenance. 

When it does that, it is almost always fixed by small b limit adjustments. Occasionally the L limit screw.


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## LewisQC (Jul 3, 2013)

FJSnoozer said:


> I am not a professional mechanic, but I set up bikes for many racers and handle their maintenance.
> 
> When it does that, it is almost always fixed by small b limit adjustments.
> 
> ...


That's what I thought as well. But I can guaranty that I tried multiple b-srew position (with sram tool and higher and lower because it was not shifting well) and low limit screw as well. Last winter and then this week again, starting from scratch. So I'm just happy that it's working now whatever the reason...


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## FJSnoozer (Mar 3, 2015)

LewisQC said:


> That's what I thought as well. But I can guaranty that I tried multiple b-srew position (with sram tool and higher and lower because it was not shifting well) and low limit screw as well. Last winter and then this week again, starting from scratch. So I'm just happy that it's working now watcher the reason...


I edited. One I set up last week needed expanded L limit. 


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