Does anybody have experiencing setting up sram 90 transmission at home? I picked up a full group and something seems off. Specifically the chain length.
In my haste, I cut my chain to match my old chain that was used on a non-transmission GX eagle setup. After seeing that it looked way too short after setup, I found out about the sram chain length calculator and ran my #’s. It recommended I run a 116 link chain. The chain I broke/cut whatever ended up at 114, so only 2 links shorter. But in the picture attached, in the smallest gear, it seems like the rear mech is still stretched crazy far out. And I’m running into the issue of it wanting to act funny and shift/not shift well between either the top 2 or bottom 2 gears depending on how I set the barrel adjuster.
Any thoughts on chain length or otherwise any advice would be appreciated. Thanks guys and gals. 
did you follow the instructions exactly?
My guess is that you didn’t pull on the lower cage to release the button from setup mode, so it’s still “locked” in the setup mode. I’ve done that plenty of times, should be fine if you pull the cage forward to release the button from the cage.
If that were the case, the chain would be very loose on the smallest cog, and it looks pretty tight in the picture.
I have no experience with Transmission but that chain looks wicked short to me.
Doesnt Sram have an app etc that tells you exactly what length for each bike?
Have you double checked the set up key position on the app?
Maybe the issue is somewhere between the 2 links (1/2 inch) short and if that key position is incorrect.
Did you set the knurled ring up against the stop prior to installing the derailleur?
I thought i did, after careful review, I missed one step. Big dummy hours
It does, as covered in the original post, I took a swing before checking that app. I ended up cutting it 2 links short of where the app recommended! Silly me, but I worked through it, and it ended up working fine lol
The knurled ring position was basically the exact problem. Along with going between “cage mode” and “setup mode”
Alright everybody, not trying to be some self righteous guy but I figured this advice could help. Here’s my lessons, after getting it pretty much dialed after thinking I completely fucked the dog.
-make sure you follow the video step for step (as other smart people mentioned above) I basically skimmed it and thought it would be fine, it was not. Follow the video exactly.
-definitely check the chain length on the app. I’m running 2 links short, and it was just dumb luck, u coulda cut it shorter on accident I just got lucky. I’m too used to winging shit and it working out.
-sequence in which you push the rear mech forward, tighten stuff, pull it back, tighten other stuff, and in the mix going from cage to setup to normal setup requires attention. The knurled ring is all in the mix too.
-I have too much ADHD brain to leave a video open while I’m going the setup. Having to keep rewinding and stuff is way too annoying to me. I watched the video and made a list on a notepad. Then went and did it start to finish, and it more or less worked perfectly. Hopefully this post can help some others 🤷🏻♀️
Could you share the video you all speak about ? :-)
As someone who does all his own servicing, I appreciate that SRAM/RS have PDF instructions with photos of all the install/service. That way I can print them out at work, and refer to them while doing the install/service. It's way more convenient than trying to constantly rewind a video with greasy fingers, as you refer to. Plus you can jot notes on the page like damper settings when working on suspension.
I would have really liked to have a PDF print out of the steps wtf! But I didn’t spend a ton of time looking for it. Still would have been sweet.
For future reference:
https://docs.sram.com/en-US/publications/5jblJ4SRpeHwjcuWG1vPy4/eagle-transmission#hashItem=eagle-transmission
(covers both mechanical and wireless Transmission). If you want to print a hard copy, there's an icon in upper right. Otherwise the web page viewer has nice links on the left to jump to relevant sections.
🤙🏻 here ya go!
https://youtu.be/2tHcG5W4Uuc
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