Eagle Shifting confusion

[Butterbean]

So I have a dual sus, running a bit of a Frankenstein 1x12. GX shifter and derailer, SLX 1x crankset, and sunrace 11-50 cassette.

 

Now, I had, what I thought, was great shifting when this set was on another bike. It's moved across to the Silverback and I'm having a funny issue... Setting up according to Srams instructions, it is sensitive to tension, and I do set the B-Gap using the tool. My bigger cog shifting is fine. Well, it's not perfect, but it's good enough and only rarely misses.

 

The small cogs are the major PITA. To get shifting right throughout the cassette, the tension seems so high it struggles to shift back into the 11t, it just struggles to drop down, I normally need to back off the power and then it drops. Stays there just fine once it has shifted down. But then, after some rides without adjustment, it starts to shift too far over from the 3rd chainring, skipping the second one, and over the smallest. and I've had a couple of rear triangle gouges when it goes too far. Reset the limit, all good. And then it happens again. The lower three cogs are the biggest issue and a total stuff up in shifting performance.

 

Chain length is right, as according to Sram. Chainline looks fine.

 

Any suggestions? Is the B-Gap setting supposed to be done with Sag on the rear shock? Does this sound like bent hanger? Eyeballing it, it looks okay. Would the B Gap even affect the smaller cogs?

 

I'll probably take it to a shop soon, but I had it set by another when the brake hose and gear outers were correctly lengthened. Same issue and actually the first time I graunched the frame with the chain...

[fanievb]

derailleur hanger alignment

[Me rida my bicycle]

Have you fitted new cable and housing?

[Butterbean]

Have you fitted new cable and housing?

Yeah housing and cable were replaced, and still have the issue.

[PeterF]

"Full suspension bikes have chain growth. As the rear wheel moves up it also moves back.  The up and rear movement increases the distance from the front chain ring. If this isn’t accounted for you could destroy chains, derailleurs, wheels or more depending on what let’s go first."

 

I borrowed the above from an online article.  Might be your problem.

 

https://bikeco.com/size-mtb-chain-video/

[DieselnDust]

So I have a dual sus, running a bit of a Frankenstein 1x12. GX shifter and derailer, SLX 1x crankset, and sunrace 11-50 cassette.

 

Now, I had, what I thought, was great shifting when this set was on another bike. It's moved across to the Silverback and I'm having a funny issue... Setting up according to Srams instructions, it is sensitive to tension, and I do set the B-Gap using the tool. My bigger cog shifting is fine. Well, it's not perfect, but it's good enough and only rarely misses.

 

The small cogs are the major PITA. To get shifting right throughout the cassette, the tension seems so high it struggles to shift back into the 11t, it just struggles to drop down, I normally need to back off the power and then it drops. Stays there just fine once it has shifted down. But then, after some rides without adjustment, it starts to shift too far over from the 3rd chainring, skipping the second one, and over the smallest. and I've had a couple of rear triangle gouges when it goes too far. Reset the limit, all good. And then it happens again. The lower three cogs are the biggest issue and a total stuff up in shifting performance.

 

Chain length is right, as according to Sram. Chainline looks fine.

 

Any suggestions? Is the B-Gap setting supposed to be done with Sag on the rear shock? Does this sound like bent hanger? Eyeballing it, it looks okay. Would the B Gap even affect the smaller cogs?

 

I'll probably take it to a shop soon, but I had it set by another when the brake hose and gear outers were correctly lengthened. Same issue and actually the first time I graunched the frame with the chain...

 

 

B-gap needs to be set with the bike sagged.

Did you fit a new chain? If not have you checked the chain wear? What type of chain is fitted?

How old is the cassette.? Sometimes an old cassette doesn't like the new chain. 

Could be derailleur hanger alignment but this would create a consistent issue that can be tuned out. If not then usually the bent hanger is clearly visible.

[Butterbean]

B-gap needs to be set with the bike sagged.

Did you fit a new chain? If not have you checked the chain wear? What type of chain is fitted?

How old is the cassette.? Sometimes an old cassette doesn't like the new chain.

Could be derailleur hanger alignment but this would create a consistent issue that can be tuned out. If not then usually the bent hanger is clearly visible.

So, I've checked the chain, it's all good, no wear on the guage. I do cycle between a KMC and a sunrace chain, I'm fairly meticulous about cleaning and swapping chains. I've replaced the hanger tonight, but also inspected the cassette and just noticed the 11th has chewed through the almost brand new freehub, along with the other separate cogs. But the 11t is really bad... Like 2/3mm... So might be that.

 

Will also try sort the B gap adjustment with sag accounted for... Hopefully those two sort things out.