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Discussion Starter · #1 ·
Recently built up a Salsa Vaya Travel for touring with a Sram 2x10 build and the rear mech shifting is absolutely abysmal. Looking for some help to see what my other options might be. Goal was to have a large gear inch range for being able to tour road and CA dirt, road shifters for drops, and reliability. The first two worked out great, the third not so much.

Current drivetrain:
  • Sram XX 42/28 Crankset
  • Sram XX front derailleur
  • Sram GX 2.1 rear derailleur
  • SunRace 11/40 rear cassette
  • Sram Rival Shifters

On a previous Vaya built I had XT 785 with bar ends. It was stolen so with this build I was looking to do the same sort of build but with brifters and a narrower q-factor. The problem I'm having though is this GX rear is total garbage and I'm not sure where to go next. There is so much play in the mounting bolt that getting consistent performance seems nearly impossible. I have it indexed properly but any little bump throws it out and for bike packing that doesn't really make much sense as I spend as much time trying to get it back in (often by physically moving the mech due to the play) as I do riding it. I figured with a 10 speed rear I wouldn't have this sort of trouble.

All this to say what might my other options be at this point? I can't seem to find a sram 1:1 pull rear alternative that can take this chain wrap and large tooth combo. From research this bolt play seems to be a common problem with GX 2.1's as well as X9 so I'm not sure what to do. Have thought about Rohloff but really don't want to spend that kind of money while no longer be able to swap between 700c and 650b. Thanks for your help!

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Discussion Starter · #6 ·
Always check the derailleur hanger with a proper alignment gauge, if it's a little off that can make a big difference.
Right but the issue seems to be with the bolt design of this rear mech it allows for lateral play which can then translate to vertical play in the derailleur. I've never had this experience with a rear mech before. It doesn't mount tight to the dropout. Can wiggle it all over the place.
 

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Discussion Starter · #8 ·
Lower end 12-speed derailleurs do the same thing and they still shift fine. Always worth checking the hanger, it's usually the first thing I do when adjusting derailleurs.
I've read mixed things about this play being common, and this play introducing shifting issues. In my case I can get it all setup and shifting properly. A day or two later while on the road it will begin mis-shifting. I'll try to re-index it and it wont seem to index properly. But then if I physically nudge the rear mech (usually away from the wheel) I can find alignment again and thus indexing and then this process repeats. So seemingly the mech is coming out of alignment and the only thing I can think of is that play in the bolt. 🤷‍♂️
 

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SO the first thing I notice is that you are using a Sunrace cassette 11-40. The GX type 2.1 has a max capacity of 36T i.e. its designed to work with the SRAM 11-36 cassette. SO I wonder if you have not over extended the rear derailleur pulley cage and damaged the clutch mechanism so that its not articulating smoothly causing your shifting issues
 

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I've read mixed things about this play being common, and this play introducing shifting issues. In my case I can get it all setup and shifting properly. A day or two later while on the road it will begin mis-shifting. I'll try to re-index it and it wont seem to index properly. But then if I physically nudge the rear mech (usually away from the wheel) I can find alignment again and thus indexing and then this process repeats. So seemingly the mech is coming out of alignment and the only thing I can think of is that play in the bolt. ?‍♂
Well if you don't check all the boxes then you just don't know. Gotta eliminate all possible issues before settling in one thing to blame.
 

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Discussion Starter · #11 ·
SO the first thing I notice is that you are using a Sunrace cassette 11-40. The GX type 2.1 has a max capacity of 36T i.e. its designed to work with the SRAM 11-36 cassette. SO I wonder if you have not over extended the rear derailleur pulley cage and damaged the clutch mechanism so that its not articulating smoothly causing your shifting issues
Copy, that could make sense. I've seen people who have successfully run this setup and and the stock b-screw works fine with the 40t but totally get that it's not within spec. I guess if I dropped to a 11-36 in the rear I could re-chain the front 40/26 and keep the gear inches pretty close.

Well if you don't check all the boxes then you just don't know. Gotta eliminate all possible issues before settling in one thing to blame.
I can take it up to a shop and have them measure it. I just don't understand if this were the case how I'd be able to get it indexed properly and then over the course of a day it comes out.
 

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I've got my GX 2.1 long cage working fine with a 11-42, so I'm not sure that it's the max gear that's the problem. It really depends since the derailleur comes in three cage lengths for different gear capacities.

If you really think the derailleur is moving side to side on the derailleur hanger bolt too much, try adding a shim/washer between the derailleur hanger and the derailleur. A really cheap thing to do would be to cut up an aluminum can in the form of a washer (using gloves and scissors), then place that around the mounting bolt and see what kind of play you have. Add more shims as necessary.

You'll know you've added too many shims when the derailleur binds and you can't rotate it out of the way, like when removing the wheel. Though really, that would be a fine test- bind the derailleur in place (maybe use a thicker shim, cut from something like a plastic bottle) and see if you still have the shifting problem.

edit: note that this is assuming that the play translational (side to side), and isn't due to the hole in the derailleur being too large for the bolt and wobbling (roll/yaw). But using many shims to get the derailleur to completely bind will fix the wobbling issue too.
 

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Copy, that could make sense. I've seen people who have successfully run this setup and and the stock b-screw works fine with the 40t but totally get that it's not within spec. I guess if I dropped to a 11-36 in the rear I could re-chain the front 40/26 and keep the gear inches pretty close.

I can take it up to a shop and have them measure it. I just don't understand if this were the case how I'd be able to get it indexed properly and then over the course of a day it comes out.
Its entirely possible to run it without issues but then that may be with a longer than spec chain.This then introduces some chaining sprocket combinations limitations. It's not possible for me to give you any definitive solutions without the bike on a stand in front of me. If you get it into works stand and film the shifting through the gears we may be able to point to where the issues are. For its just a bit of shooting in the dark.
I doubt its the derailleur mounting bolt but check that the circlip on the back is still in place. I've got one of the XO1 2.1 2x10 rer derailleurs on my old 2008 Scalpel which I keep maintained and usable for my wife (she gets along better with the smaller wheels) and there is absolutely no play in the mounting bolt. The derailleur is rock solid on the bolt. does not jiggle or move sideways on the shaft. Only the pulley cage moves and it does so very smoothly as does the articulation at mounting bolt
 

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Discussion Starter · #14 ·
I've got my GX 2.1 long cage working fine with a 11-42, so I'm not sure that it's the max gear that's the problem. It really depends since the derailleur comes in three cage lengths for different gear capacities.
This is the long cage as well. You're running it with 2x 11-42?

Thank you for the shim advice! I'll either grab some very thin washers or cut up the coke can and see if that does the trick.

Its entirely possible to run it without issues but then that may be with a longer than spec chain.This then introduces some chaining sprocket combinations limitations. It's not possible for me to give you any definitive solutions without the bike on a stand in front of me.
Totally makes sense. I did spec the chain to the correct length for this combo. Planning on making sure the hanger is straight and eliminating the play in the rear mech bolt and then will go from there. Thank you!
 

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Thank you for the shim advice! I'll either grab some very thin washers or cut up the coke can and see if that does the trick.
Putting a shim between the derailleur mounting bolt and the hanger will do nothing to eliminate the play, you'd have to disassemble the pivot bolt and put it in between the bolt and derailleur.

Is the derailleur new? Or new-ish? As mentioned 12- speed NX and SX derailleurs have a ton of play in the pivot bolt even when brand new and they shift fine. I don't know, maybe a coke can shim hack could help but I've been working on bikes for a living for over 30 years and have never resorted to trying something like that to make a bike shift well.
 

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Discussion Starter · #16 · (Edited)
Putting a shim between the derailleur mounting bolt and the hanger will do nothing to eliminate the play, you'd have to disassemble the pivot bolt and put it in between the bolt and derailleur.
On closer inspection you're totally right. It looks like I'd have to get behind the cir-clip to take the slack out (if this is in fact the issue). Derailleur says it was manufactured in '19. I bought it new within the last year and have less than 300 miles on it. Vid of the play is here:
 
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