Sram Transmission issues

My XO Transmission is also in micro adjust position 1 of 14. Anything other than 1 and it will occasionally drop to the next smaller cog, so it is not in the optimal position, but at least it works. I hope someone on here knows how to reset or adjust the micro adjust as I have been putting off emailing Sram about it.

So did a bit of digging, and it seems like micro-adjustement issues are related to initial setup and rear hub tolerancing (mainly XD freehub and end cap). Found this response someone got from SRAM rider support in a Reddit thread:

https://www.reddit.com/r/mountainbiking/comments/13wrki7/comment/jmlxo0f/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

TL:DR:
- Installation should be done with the micro-adjustement setting at 7 of 14.
- With the cassette installed, the distance from the end of the cassette to the end of the end cap should be 3.4mm.
- With the cassette removed, the other measurement to check is the freehub itself. Measure from the "little shelf" of the freehub body, to the end of the end cap. This distance should be 44.1mm, +/- 0.3mm.

There's a 17 pages thread on MTBR regarding people having issues with T-Type drivetrains, might worth a read.

https://www.mtbr.com/threads/got-sram-transmission-got-problems-post-he…

There is a very long thread of folks with similar issues here; one thing that seems common is that it happens more w/ GX than the other versions, especially GX cassettes. Hopefully something in there will give you some pointers.

I’m not a fan of Transmission at all. With no limit screws, B tension adjustment and a very narrow window of micro adjustment it simply can not work on every frame/hub combo that exists. It relies heavily on somewhat exact tolerances, which the bike industry is very, very poor at executing. I’ve had some bikes shift absolutely flawlessly, some barely function, and most shift “ok” for a 4 figure drivechain. Most of the ones I’ve touched, my own bike included, have a huge problem dropping off of the “adjustment cog” down into the smaller cogs, usually requiring a double shift to fully get the chain to move. My only thought in fixing any of this is on Sram. Their method of adjustment is flawed. Each time you micro adjust the derailleur, you effect the position of the derailleur across the entire range of the cassette, fixing maybe that specific issue, but potentially creating another at a different point in the cassette. Sram is giving the sense of adjustment, but is actually just hoping all the tolerances add up to a working drivechain. In my mind, the only fix would be to have a micro adjustment system similar to how Campagnolo does it, where each cog has it’s own range of adjustment, that is adjusted then locked into place. Creating basically a custom map of the cassette which would negate most if not all of any tolerance issues.

"related to initial setup and rear hub tolerancing (mainly XD freehub and end cap)."

Which is hilarious because even srams OWN XD drivers don't actually follow their own drawings of the XD standard which other brands license from them. The standard shows a partially exposed outer bearing but SRAM themselves typically have XD drivers which have a smaller OD bearing which is fully pressed into the driver.  

In a related story, press fit bottom brackets are easy to install and don't creak**

**as long as frame tolerances are up to spec

This. 100%. I was just chatting about the issue with adjusting trim on a single cog and how it impacts the entire range. It's really stupid they did it that way instead of allowing individual trim adjustments to be mapped to those individual cogs. 

I can only hope they offer this as a firmware update at some point in the future… or they will sweep it under the rug like did with the AXS derailleur battery contact wear issues and the large swath of AXS derailleurs that seemingly can only be adjusted to shift either the larger or smaller half of the cassette, but not both, that they quietly warranty for me every time without explanation. I’m on derailleur number 9 with this issue.

This, Press fit is an industrial standard for bearings... If your bike brand cant make a round hole ... well thats just the rubbish we pay thousands for... It really bothers me people slam Pressfit but no sorry its your shitty quality frame

I've had 2 custom frames built for me, both with pressfit and never have i had a noise come from those BB's.

You speak truth Sir. It seems a lot of people don't like truth. Strange. Keep up the good work.

I have two bikes with Transmission, X0 level. Both are in micro-adjustment setting 1 and while the system works, both bikes could really use another 1-2 clicks to better line up the guide pulley. I did some research, found the reddit post linked above and re-installed with micro-adjust in setting 7. I still ended up needing to set micro-adjust to 1 after all that. I'm running DT 350 hubs on both bikes so not exactly an exotic setup. 

Has anyone with these Transmission micro-adjust issues tried using washers or shims to space out their hub end caps or freehub? I know that's super janky, but it sounds like it's a simple alignment/tolerance problem, so maybe it could be solved with a simple (but janky) solution.

It's not the cassette or hub spacing that is the problem, it's the "between gear" spacing/tolerance issue.

Sram says the distance between the outside of the mounted cassette and the end of the hub end cap should be 3.4mm, mine is 3.53mm (I9 1/1 hub) so less than 1 micro shift (0.2mm) off. All of the rest of tolerance buildup is in the cassette and derailleur, so my cassette and derailleur are about 1.5mm off from nominal alignment. That's big. And I blame it on the short links of the parallelogram with tiny holes riding on tiny pins that need to be very precisely aligned. However, it is curious that the majority of people who are having issues with a single gear, it is the third (38 tooth) gear which is where the three pinned cogs connect to the nine smaller cogs that are machined as a unit. At this price, I expected better quality, but a simple software update that allowed for individual gear adjustment and a wider total range of adjustment seems like would be the preferred fix over a bunch of warranty replacements.

This is interesting.  I have a lot of bikes (my problem, no need to shame me) and I have XX SLs on 4 of them, XX on 2 of them, XO on 3 of them and GX on 2 of them.  The only one that I had to mess with a bit to make work was one of the XOs and it is still a little flaky if I don't reset it occasionally.  Microadjust on that one has to be 2 or I get clicking in 9th gear, have to shift to 8 and then back to 9 to clear it quickly.  To this point, given that the rest of them have never had an issue, I assumed I was doing something wrong and it was annoying the heck out of me that I couldn't figure out what it was.  There's cursing every time I hear the clicking start again.  

From memory, the cassette felt a little off when I installed it so I'm betting that "- With the cassette removed, the other measurement to check is the freehub itself. Measure from the "little shelf" of the freehub body, to the end of the end cap. This distance should be 44.1mm, +/- 0.3mm." is going to be out of tolerance.  I'll measure that as soon as I can.

I still don't understand why microadjust isn't mapped to individual cogs.  Seems like such an easy solution to this problem for everyone that has it.

I'm experiencing peak satisfaction this year with no longer making a living as a bike mechanic; sram should be on my holiday card list. 10 years ago I got ribbed by the more senior mechanics for the amount of time I spent pulling up technical documents. They arguably were right, then. Instead of a 6-pack maybe y'all can bring your guy or gal fresh batteries for their calipers :D

I've had similar issues on a brand new YT Capra Uncaged 12 and I was able to finally get everything working by factory reseting all AXS components and reinstalling the lates firmware. I am still operating in a MicroAdjust position of 1/14. I've put instructions for reinstalling firmware in a blog post linked below. From other forums and talking to SRAM/YT/Crankbrothers there are a myriad of causes for poor shifting performance. This is the list I was able to compile:

1. Not following setup instructions precisely

2. Entering incorrect information into the SRAM AXS app when getting setup instructions

3. Improper pairing of AXS components

4. Incorrect chain length

5. Powerlink is not shut completely

6. Using the wrong setup key position

7. Incorrect installation of the bushing frame insert

8. Improperly torqued components

9. Using the wrong setup cog

10. Slack in the chain after setup

11. Misalignment of the knurled ring mark with the mark on the full mount of the derailleur

12. Failing to use micro adjustment for alignment

13. Testing the drivetrain in the bike stand only instead of testing under load

14. Firmware issues

15. Wearing in the components to reduce noise

16. Missing spacers or bushings

17. Bad manufacturing tolerances in the bike hub, driver, end-caps, cassette, or derailleur

18. Bad manufacturing tolerances in the UDH compatible frame

Blog post here.