SRAM GX/NX 12sp install and adjustment tips

[NotSoBigBen]

Since I have noticed that this topic comes up quite often and there are certainly very knowledgeable guys on the hub ... how about giving some guidelines regarding initial install and setup tips in just one thread?

Step by step with pics for us in the back por favor 😉

For example things I wonder about ... b-screw at installation,  chain length, correct use of the 'red tool'

General thoughts about chain line and how to check it

[Steady Spin]

I initially worked from this SRAM tech video

Seems like not all bikes are equal and this will mostly likely work for 90% of them. 

More wizardry advice will be great. 

[thebob]

When using the red tool for the b-screw gap on a full sus bike you must have the rear  of the bike sitting at the sag point to get the correct gap

[NotSoBigBen]

28 minutes ago, thebob said:

When using the red tool for the b-screw gap on a full sus bike you must have the rear  of the bike sitting at the sag point to get the correct gap

What would be the easiest way to do that? Does it mean sitting on the bike while someone else checks that or is there an easier way ...

[PeterF]

59 minutes ago, NotSoBigBen said:

What would be the easiest way to do that? Does it mean sitting on the bike while someone else checks that or is there an easier way ...

Probably letting the air out of the shock would be the easiest.  You will obviously need a shock pump though.

[Steady Spin]

I put weight on the saddle and hung over using the camera on my phone to see the derailleur pulley. 

Not 100% accurate of graceful. Best to let air out of the shock and set it then. 

I chose not to do that since getting my shock back to 280psi is a massive pain. 

[droo]

2 hours ago, Steady Spin said:

I initially worked from this SRAM tech video

Seems like not all bikes are equal and this will mostly likely work for 90% of them. 

More wizardry advice will be great. 

^ this and a bit of experience with derailleurs and you're good.

 

The only things different from older RDs are the B gap and the fact that chain length is critical. Most people leave the chain a link too long and the shifting sucks as a result. It needs to be as short as it can be while still leaving enough to cycle through travel in the 50 / 52T.

[NotSoBigBen]

36 minutes ago, PeterF said:

Probably letting the air out of the shock would be the easiest.  You will obviously need a shock pump though.

'At the sag point' so not all the air?

[Steady Spin]

1 minute ago, NotSoBigBen said:

'At the sag point' so not all the air?

I was also confused about this one. Tried it at both fully deflated and again at 30% sag.

Neither worked on the Forbidden but 30% seemed to be the sweet spot for my Evil.

[W@nted]

I am struggling with my gx axs setup. Instructions from sram says to do micro adjustment with chain on second cog from the top. If i get it to run silent on the second cog from the top, I get lousy shifting between the 9,10 and 11th cogs from the top. Also a very annoying ticking sound on the 4th smallest cog (possibly the gx cassette).

 

If I di the micro adjustment to sort the noise out on the smaller gears, the shifting is terrible on the largest 2 cogs.

 

derailleur hangar is brand new, but is it possibly misaligned to cause this issue?

[droo]

A new hanger may not be perfectly straight once installed. Get a hanger alignment tool on it and see.

[Steady Spin]

54 minutes ago, W@nted said:

I am struggling with my gx axs setup. Instructions from sram says to do micro adjustment with chain on second cog from the top. If i get it to run silent on the second cog from the top, I get lousy shifting between the 9,10 and 11th cogs from the top. Also a very annoying ticking sound on the 4th smallest cog (possibly the gx cassette).

 

If I di the micro adjustment to sort the noise out on the smaller gears, the shifting is terrible on the largest 2 cogs.

 

derailleur hangar is brand new, but is it possibly misaligned to cause this issue?

Is your quicklink the right way round? Sometimes this can be overlooked. 

[W@nted]

22 minutes ago, Steady Spin said:

Is your quicklink the right way round? Sometimes this can be overlooked. 

Will double check, but almost sure it is correct, thanks

[DieselnDust]

22 hours ago, W@nted said:

I am struggling with my gx axs setup. Instructions from sram says to do micro adjustment with chain on second cog from the top. If i get it to run silent on the second cog from the top, I get lousy shifting between the 9,10 and 11th cogs from the top. Also a very annoying ticking sound on the 4th smallest cog (possibly the gx cassette).

 

If I di the micro adjustment to sort the noise out on the smaller gears, the shifting is terrible on the largest 2 cogs.

 

derailleur hangar is brand new, but is it possibly misaligned to cause this issue?

initial adjustment should be done with the chain on the 5th, 6th or 7th sprocket.

Micro adjustment should be conducted on the 2nd sprocket and 11th sprocket. 

Once the derailleur is set up in the middle of the cassette do the microadjustments on the 2nd and or 11th

 

if the chain is ticking check the quiklink that both links are fully engaged. 

Ensure that the chain is running correctly on the NW tension pulley wheel (that's the bottom one)

 

To check chain line get a 1m long steel rule and hold it thin edge against the inner side of the chainring. It now cross over the 7th  sprocket on the cassette (counting from the drop out) or thereabouts - there is bit of tolerance involved since this is the bike industry that uses civil engineering tolerances and not mechanical Eng tolerances

 

[NotSoBigBen]

10 minutes ago, DieselnDust said:

initial adjustment should be done with the chain on the 5th, 6th or 7th sprocket.

Micro adjustment should be conducted on the 2nd sprocket and 11th sprocket. 

Once the derailleur is set up in the middle of the cassette do the microadjustments on the 2nd and or 11th

 

if the chain is ticking check the quiklink that both links are fully engaged. 

Ensure that the chain is running correctly on the NW tension pulley wheel (that's the bottom one)

 

To check chain line get a 1m long steel rule and hold it thin edge against the inner side of the chainring. It now cross over the 7th  sprocket on the cassette (counting from the drop out) or thereabouts - there is bit of tolerance involved since this is the bike industry that uses civil engineering tolerances and not mechanical Eng tolerances

 

Much appreciated DnD!

[Chadvdw67]

The ticking could be burrs on the cassette at those sprockets, my GX cassette did it as well on the same sprocket as yours, I think it is a fairly common problem