Modern 1x12 eagle drivetrain slow gear changes ???

[kyle888]

So I’ve recently built a modern 650b hardtail with an NX eagle 1x12 drivetrain. I’m confident I’ve set everything up properly as I’ve built many bikes over the years.

My concern is that I click the shifter either way and have to wait a good couple of seconds for it to actually shift which I assume is the cassette turning until a shift ramp. Once shifted it works perfectly in every gear and moves up and down smoothly just the delay is annoying.

Is this normal for eagle 1x12? My old 1x9 Shimano would shift straight after pushing the shifter so you could manage that slight reduction of load through the cranks when it shifted but with the 1x12 it’s like your going easy and just waiting for the shift.

Anyone else find this?

Tempted to swap it out for 1x10 Shimano to be honest.

Cheers Kyle

 

[ishaw]

Not sure, but that doesn't sound right at all. No experience of 12s sram, but just built an 11sp slx build for my youngest and have had trouble getting the shifting just right. It's a new gear hanger so they'd straight, new cassette and chain too. I just can't quite get it in the sweet spot. Seem to have to set it up so that on the upshift, it needs to be pushed just past the click to shift properly. Comes down fine on the downshift. No 2 seconds delay, all pretty instant.

Never had this before, have one other 11sp build, various 10s and 9s.

 

[7Speed]

I have sram 12sp on my road bike and there are no delays - can’t imagine the MTB stuff is any different?

 

[Frankenorange]

So I’ve recently built a modern 650b hardtail with an NX eagle 1x12 drivetrain. I’m confident I’ve set everything up properly as I’ve built many bikes over the years.

My concern is that I click the shifter either way and have to wait a good couple of seconds for it to actually shift which I assume is the cassette turning until a shift ramp. Once shifted it works perfectly in every gear and moves up and down smoothly just the delay is annoying.

Is this normal for eagle 1x12? My old 1x9 Shimano would shift straight after pushing the shifter so you could manage that slight reduction of load through the cranks when it shifted but with the 1x12 it’s like your going easy and just waiting for the shift.

Anyone else find this?

Tempted to swap it out for 1x10 Shimano to be honest.

Cheers Kyle

Apologies if you know all of what comes next.

If all the bits are brand new then it could just be that the upper pulley needs to be closer to the cassette. There are little jigs you can use for this or there are dimensions kicking about on t'internet.

Another thing, and i don't know if this is the case with your NX rear mech, is that some models of Sram mechs had alot of play in the mounting bolt, from new. I have no idea if this was machining/casting errors but it never seemed right to me. In other models there is no play in the mounting bolt!?!. If the non-floppy examples are just because the mounting bolts are a bit fatter then it might be possible to fit a bolt from a model known to be a better fit?. I am familiar with Force, X9 and X0 10 speed and XX1 11 speed. Don't know zip about 12 speeds.

Chains can cause all manner of probs. It seems alot of people say a Shimano XT or XTR 12 speed chain (m8100 and m9100) shift better than a Sram chain. Might just be nonsense, but there does seem to be alot of positive forum chat, over many years, regarding this. The chain plates of XT and XTR have the same profiles and it is just hollow pins and one different finish that the XTR chain has on the XT.

If the parts are used then it could be anything and it will come down to a process of elimination. Bent hanger, sticky cables, sticky mech pivots, worn chain, worn cog teeth etc

@benjabbi is your man for this stuff. He knows his onions.

 

[kyle888]

Not sure, but that doesn't sound right at all. No experience of 12s sram, but just built an 11sp slx build for my youngest and have had trouble getting the shifting just right. It's a new gear hanger so they'd straight, new cassette and chain too. I just can't quite get it in the sweet spot. Seem to have to set it up so that on the upshift, it needs to be pushed just past the click to shift properly. Comes down fine on the downshift. No 2 seconds delay, all pretty instant.

Never had this before, have one other 11sp build, various 10s and 9s.

I experienced what you are describing on a setup once before and the issue was a cheap non Shimano gear cable. Swapped to Shimano and shifting was perfect I assumed the cheap cable stretched a bit on the upshift so wouldn’t move up a gear without the extra little push on the shifter.
Unless it’s a Shimano cable then maybe not this.

Kyle

 

[kyle888]

Apologies if you know all of what comes next.

If all the bits are brand new then it could just be that the upper pulley needs to be closer to the cassette. There are little jigs you can use for this or there are dimensions kicking about on t'internet.

Another thing, and i don't know if this is the case with your NX rear mech, is that some models of Sram mechs had alot of play in the mounting bolt, from new. I have no idea if this was machining/casting errors but it never seemed right to me. In other models there is no play in the mounting bolt!?!. If the non-floppy examples are just because the mounting bolts are a bit fatter then it might be possible to fit a bolt from a model known to be a better fit?. I am familiar with Force, X9 and X0 10 speed and XX1 11 speed. Don't know zip about 12 speeds.

Chains can cause all manner of probs. It seems alot of people say a Shimano XT or XTR 12 speed chain (m8100 and m9100) shift better than a Sram chain. Might just be nonsense, but there does seem to be alot of positive forum chat, over many years, regarding this. The chain plates of XT and XTR have the same profiles and it is just hollow pins and one different finish that the XTR chain has on the XT.

If the parts are used then it could be anything and it will come down to a process of elimination. Bent hanger, sticky cables, sticky mech pivots, worn chain, worn cog teeth etc

@benjabbi is your man for this stuff. He knows his onions.

Thanks for the reply it’s a used Groupset but not had much use. I’ll check the jockey wheel distance from the cogs and see if that helps.
It shifts up and down fine no rubbing when in a gear just the delay.
I’ve read some people say that’s just how it is with eagle cause of the big jumps on the cassette

Kyle

 

[bikeworkshop]

Drag in the cable causes shift delay.

Long cable outers make it worse.

Check your outer is good quality (beware fakes, and I use 5mm)
use top quality cutters, and check the holes at the cut ends are fully open.
Routing and curves all need to be super smooth.

 

[benjabbi]

I think @Frankenorange and @bikeworkshop have covered what I'd say.
Make sure the cable runs freely through the outer and takes the path of least resistance. As @bikeworkshop suggests don't skimp on either inner or outer. Make sure the hanger is bang on straight. Due to the massive pivot to jockey offset Eagle is pretty sensitive to the chain being the correct length, this differs between hardtails and full suss. Google it for a proper explanation. As @Frankenorange says the B-tension adjustment is critical. There is a tool for the correct set up, it's cheap and removes the guesswork. The further away the jockey is from the sprocket, the further sideways it has to move to make the chain move to th next sprocket. We're talking small distances but does make a difference.
You don't say if it's across the whole cassette? The bigger two sprockets on an NX cassette have a slight narrow/wide profile and the chain doesn't always hit it right first time. As @Frankenorange alludes to, NX is not very good quality. It could just be worn out, it'll never be fast and accurate if there's too much play in the mech.