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Discussion Starter · #1 ·
Sorry if this is discussed somewhere else. I couldn't find it.

I have the new Revved Smash. I'm new to GG and new to Eagle (GX 11sp previously).

I hop the chain on back-pedal when in the 50t gear. The chainline looks pretty angular in this configuration. I heard that shorter chainstay bikes tend to have this issue. The bike came with a chain pre-shortened, which I installed.

Any advice? Any words of wisdom? If this is the wrong place to post, let me know.
 

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Eagle drivetrains are notoriously finicky. Use the little red tool to adjust the B-screw tension so the upper pulley lines up exactly where it needs to in relationship to the 50T chainring. See the top video on this Google Search: https://www.google.com/search?q=sra...e.1.69i57j0.5515j0j7&sourceid=chrome&ie=UTF-8

That should do it :)

FYI - I've found even 1mm difference (too much or too little tension) can cause issues. Dial that **** in! Sometimes you gotta play with it a bit.
 

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I have experienced this over multiple drivetrains with different configurations of speeds, cassettes, derailluers, etc. Think it has just become a common problem with anything that is 10spd and up. For my NX Eagle drive train it happens after a couple of backpedals so not a huge worry for me as long as it does not happen while I am attempting to ratchet on a technical climb/rocky section.
 

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The NX 12 speed on my Chamelon will do it from time to time. Either back pedal, or something if I roll backwards on a hill it will attempt to drop -depending on how far I roll back.

Pretty common, unfortunately.
 

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It's Eagle, it's 12sp, it's life.

Don't backpedal too much or get 11sp.

I sold my Eagle stuff for this reason, too finicky, needed lots of lubing, backpedaling sucked, and it didn't always shift well.

GX 11sp is better, but the e13 cassettes suck!

I'm looking at an upgrade, either a Garbaruk cassette or Shimano 12sp

All that aside, chain drop is a bit different than a chain going down to the next cog. So you dropped the chain between the cassette and the hub? If so, then the derailleur is out of adjustment. If you just dropped down to the next cog, then that's par for the course...
 

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Sorry if this is discussed somewhere else. I couldn't find it.

I have the new Revved Smash. I'm new to GG and new to Eagle (GX 11sp previously).

I hop the chain on back-pedal when in the 50t gear. The chainline looks pretty angular in this configuration. I heard that shorter chainstay bikes tend to have this issue. The bike came with a chain pre-shortened, which I installed.

Any advice? Any words of wisdom? If this is the wrong place to post, let me know.
Did you align the hanger? I have zero issues with my Eagle set up when I'm diligent with B tension and making sure the hanger is aligned. I've used the same drivetrain across multiple bikes now.

Sent from my iPhone using Tapatalk
 

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My GX Eagle has been bulletproof and zero hassles. Lots of love taps on the derailleur and no problems shifting or backpedaling. It's not an Eagle issue it's a setup problem.

OP - do what you can to improve that chainline if you have the ability to flip the chainring or move spacers around that will help. Maybe post a few photos so we can see what the situation is?
 

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You can't get away from it with your current setup, it's plain physics of absolutely horrible chainline when in that combo on a 1x setup. Want to solve this problem? Check what cranks and/or ring you have, if it's boost and you're not running a 2.5"> tyre, then either get yourself a regular 51mm chainline crank or reverse your ring to give that chainline. 148x12 boost is not enough to require spacing your rings out further, it now in fact puts the cassette in the right place relative to the rings on a 51mm chainline crank/ring setup, boost cranks/rings are only needed if you're running plus tyres.
 

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On other bikes with 1x and short CS where we have had the chain backpedalling issue flipping the ring or swapping in another ring with less offset has solved the issue. You may also be able to move spacers from the DS to the NDS depending on how your bike is setup. Lynx is correct it's a geometry problem so do what you can to make the chain angle less acute in the biggest cog.
 

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It's Eagle, it's 12sp, it's life.
Strongly disagree. I have zero backpedal issues with Eagle. If your B screw and chain-line are correct and you still have issues, confirm proper limit screw settings (if your high limit is not set far enough inboard there may not be enough tension inboard to keep the chain on the sprocket) and proper hanger alignment. I used to think Eagle was the worst drive trains I'd ever owned until I spent 50$ on a hanger alignment tool. It's one of the best bike purchases you can make IMO.
 

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I used to think Eagle was the worst drive trains I'd ever owned until I spent 50$ on a hanger alignment tool. It's one of the best bike purchases you can make IMO.
Agreed on both counts. It's amazing when you check a brand new derailleur hanger with the alignment tool and have to get it straight before you even bother adjusting the shifting, but I've seen it time and time again.
 

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Discussion Starter · #14 ·
Thanks for all the feedback. I didn't really make any progress over the weekend but I rode a bunch. Honestly, I'm not using the big Eagle ring on any of my local trails. I was never left wanting when I had 1x11 GX previously. I'll sort it out. The B pillar adjustment does alleviate a little bit of tension from the chain, so it could be the ticket (when I backpedal it, I can see the chain straining to line up on the big ring).
 

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Talking with my local shop last week they told me that Eagle is one of the most finicky setups they have ever dealt with. Something as simple as a 1/8 - 1/4 turn of one of the limit screws an seriously screw with your shifting. So it is one of those things that they told me if I start messing with myself that I need to be very patient and calculated with my adjustments. Once you get the hang of it and realize the pitfalls you get used to it and automatically adjust. But yes, the derailleur hanger being out of whack has become pretty common.
 

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I have an e13 cassette combined with SRAM stuff on my 2018 MT and have the same problems back-pedaling in the bigger rings. It's interesting that I have no issues with my double chain ring setup on my Ibis on which I am using a 1x11 GX 10-42 (I think) with shimano chain rings and shimano derailleurs. I was even getting away with 26 - 38 with the chain rings for a while but had a very slack chain when in 10 on the cassette and 26 on the rings. I am able to use all the gears regardless of the chain ring and only occasionally lost the chain off the chain rings on a bumpy descent (hence went back to 26 - 36). It's tempting to re-awaken the multi-chain ring debate but no one wants that!
 

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Discussion Starter · #18 ·
Update: not much of an update really. I have over one hundred miles on the bike. It does still drop on backpedal in the big ring but not right away, so it's been completely a non-issue (usually about two and half to three rotations will cause it to drop). I checked everything. Even bought the SRAM chain adjustment tool (red doohickey).
 

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Update: not much of an update really. I have over one hundred miles on the bike. It does still drop on backpedal in the big ring but not right away, so it's been completely a non-issue (usually about two and half to three rotations will cause it to drop). I checked everything. Even bought the SRAM chain adjustment tool (red doohickey).
Does this mean you don't recommend the Eagle setup then? I'm looking to convert to 12 speed, and I was thinking SRAM.
 

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Does this mean you don't recommend the Eagle setup then? I'm looking to convert to 12 speed, and I was thinking SRAM.
I have 12+ bikes all with GX Eagle and other than a little adjustment when they were brand new, they've worked flawlessly. Don't hesitate to buy SRAM or Shimano, they both function great.
 
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