The impossible gear dilemma.

[Steady Spin]

Quick one. 

New build and I just can’t get the gears to index 100%
 

NX 12 speed 11-50 cassette used 

GX derailleur and NX shifter used

GX chain used but at less than 0.25 wear

GX crank new  

New cables and housings  

The parts came off the old and the crank is new. Boost spacing on the old frame and the new frame. No changes made to the chainline and it looks correct. 

Typically everything shifts perfectly on the stand but during a ride the middle of the cassette is finicky and also shifting all the way to the 11t doesn’t happen. 

B-tension was set at static, 30% sag, and full compression to test. Full compression is as close to usable as I can get it. I used the new SRAM white tool to set it. 

H and L screws align 100% with the cassette. 

Bike in question is a Forbidden with the idler wheel and lower chainguide. 

Edited April 3, 2022 by Steady Spin

[Steady Spin]

Checked hanger alignment and hanger bolt as well as rear axle torque. 

[Steady Spin]

Just checked chainline and it is 51.6mm. Forbidden states 52mm so I’m close enough. 

[Steady Spin]

Conversation with myself 😂

Found a tech video from Forbidden. 

Turns out you have to back the b-tension all the wait out until you have a slack chain. Then adjust until there is tension and add one full turn. 

From here you add and remove half a turn until everything is fine. 

99.9% there. I blame an old cassette for the rest. 

[RobertWhitehead]

Glad you got yourself sorted 😁. Sometimes you just need to have a conversation with yourself to discuss the situation 🤣👍

[Knersboy]

Man there is absolutely no way I would have thought to check for gear setting quirks from a frame manufacturer. Your monologue has taught me something so thanks.

[Steady Spin]

17 minutes ago, Knersboy said:

Man there is absolutely no way I would have thought to check for gear setting quirks from a frame manufacturer. Your monologue has taught me something so thanks.

With the pivot and idler I figures there must have been something different with the chain growth. Very interesting one indeed. 

[Steady Spin]

37 minutes ago, RobertWhitehead said:

Glad you got yourself sorted 😁. Sometimes you just need to have a conversation with yourself to discuss the situation 🤣👍

I like being alone. I have the best time with myself 🤔

[Rolf Hansen]

Reminds me of the wooden parrot story.

Glad you got it sorted.

[madmarc]

isn't the white tool for AXS and red for GX/NX - Just asking because with white/AXS you line it up with the 2nd lowest gear and the red/GX/NX you line it up with the lowest gear.

[Steady Spin]

23 minutes ago, madmarc said:

isn't the white tool for AXS and red for GX/NX - Just asking because with white/AXS you line it up with the 2nd lowest gear and the red/GX/NX you line it up with the lowest gear.

White replaced the red one.