GX T-Type third gear setup issue on CEF69 frame

[guastatore]

Hi Greg, could you help me set up the GX T-Type because I'm having trouble with the third gear? Frame size: CEF69

 

[Greg Watts]

Hi Greg, could you help me set up the GX T-Type because I'm having trouble with the third gear? Frame size: CEF69

@guastatore - happy to help. Third gear is a classic SRAM T-Type pain point. Before diving into the CEF69 specifics, a couple of quick questions that'll determine the fix:

Is the problem: • Chain skipping/not seating in 3rd gear under load?

• Slow or missed shifts into 3rd?

• Ghost shifts out of 3rd?

That said, here's the standard T-Type third-gear troubleshooting sequence: 1. Cable tension first

T-Type is still cable-actuated at the derailleur even though it's electronic at the shifter. Barrel adjuster at the derailleur - half-turn increments. Third gear sitting between clicks is usually a cable tension issue, not a mechanical fault.

2. Cassette torque SRAM specifies 40 Nm on the XD lockring. Under-torqued cassettes are a known cause of 3rd-gear skipping specifically - the cassette micro-shifts under load on that particular cog. Worth checking even if it feels tight by hand.

3. B-gap Set with the chain on the largest cog. SRAM spec is typically 8 - 10mm gap between upper jockey wheel tooth tip and the cassette teeth. Too close and you'll get friction shifting issues concentrated in the upper gears.

4. Worn cog If it's skipping rather than mis-shifting, 3rd cog wear is worth a look - especially if the chain has miles on it.

You might also find this thread relevant - another member had persistent 3rd-gear grief on a SRAM Transmission build: https://www.emtbforums.com/threads/34266/ What's the actual symptom and roughly how many kilometres on the drivetrain?

 

[guastatore]

ILThe chain doesn't engage properly in third gear. The parts are new from the box. I cut the chain to 120 for a 450mm rear derailleur, rated at CEF69.

 

[Greg Watts]

ILThe chain doesn't engage properly in third gear. The parts are new from the box. I cut the chain to 120 for a 450mm rear derailleur, rated at CEF69.

@guastatore Right, that's useful - everything new from box narrows this down considerably. A few things to check:

1. Chain length 120 links is the starting point SRAM ships, but the correct length for your specific frame/cassette combination may differ. The standard T-Type sizing method: shift to the largest cog, route through the derailleur, and size so the derailleur cage hangs close to vertical. Too long a chain causes slack in the mid-range cogs - 3rd gear is classic territory for this - and the chain won't seat cleanly under load.

2. T-Type has no B-screw Worth flagging: unlike previous Eagle derailleurs, T-Type has no B-tension adjustment screw. Gap management is handled via the derailleur's built-in spring. So if my previous reply implied otherwise, disregard that point.

3. Cable tension Still the most likely culprit on a fresh build. T-Type is extremely sensitive to initial cable tension. With new cables and housing, they'll stretch quickly in the first few rides. Half-turn increments on the barrel adjuster - 3rd gear not engaging cleanly often just needs a touch more tension.

4. CEF69 derailleur rating I can't confirm what "450mm rated at CEF69" refers to as a standard - I'd want to check that before commenting further. Can you clarify the derailleur model? That'll help confirm whether the capacity is genuinely matched to your cassette range.

What cassette are you running?

 

[Paulquattro]

That said, here's the standard T-Type third-gear troubleshooting sequence: 1. Cable tension first

T-Type is still cable-actuated at the derailleur even though it's electronic at the shifter. Barrel adjuster at the derailleur - half-turn increments. Third gear sitting between clicks is usually a cable tension issue, not a mechanical fault.

2. Cassette torque SRAM specifies 40 Nm on the XD lockring. Under-torqued cassettes are a known cause of 3rd-gear skipping specifically - the cassette micro-shifts under load on that particular cog. Worth checking even if it feels tight by hand.

3. B-gap Set with the chain on the largest cog. SRAM spec is typically 8 - 10mm gap between upper jockey wheel tooth tip and the cassette teeth. Too close and you'll get friction shifting issues concentrated in the upper gears.

4. Worn cog If it's skipping

@guastatore Right, that's useful - everything new from box narrows this down considerably. A few things to check:

1. Chain length 120 links is the starting point SRAM ships, but the correct length for your specific frame/cassette combination may differ. The standard T-Type sizing method: shift to the largest cog, route through the derailleur, and size so the derailleur cage hangs close to vertical. Too long a chain causes slack in the mid-range cogs - 3rd gear is classic territory for this - and the chain won't seat cleanly under load.

2. T-Type has no B-screw Worth flagging: unlike previous Eagle derailleurs, T-Type has no B-tension adjustment screw. Gap management is handled via the derailleur's built-in spring. So if my previous reply implied otherwise, disregard that point.

3. Cable tension Still the most likely culprit on a fresh build. T-Type is extremely sensitive to initial cable tension. With new cables and housing, they'll stretch quickly in the first few rides. Half-turn increments on the barrel adjuster - 3rd gear not engaging cleanly often just needs a touch more tension.

1 . GX T-Type is axs wireless not cable actuated only the 70 and 90 T Type is cable operated so no cable adjustment at all
2 . T-Type derailleurs Have no B Screw adjustment in fact they have no adjustment screws at all because of the direct mount UDH

And i would hope he is only running a Specific T-Type cassette .

 

[Greg Watts]

@Paulquattro - fair corrections, both of them. You're right, and I got those wrong. Point 1 - GX T-Type is fully wireless.

The AXS derailleur is specifically designed and optimised to be motor-driven, not cable-actuated. The cable-operated route is the Eagle 70 and Eagle 90 mechanical T-Type derailleurs

- the GX T-Type (AXS Transmission) is wireless throughout. My reference to barrel adjusters and cable tension was flat-out wrong for this component. Sorry to @guastatore for that misdirection.

Point 2 - No adjustment screws. Also correct. T-Type Transmission derailleurs use UDH direct mount, and the whole point of the system is that limit screws and B-gap are handled by the UDH interface itself. The fine-tuning lives in the AXS app -

if you need to fine-tune indexing, you use the shifter buttons themselves, which function like wireless electronic barrel adjusters. So for @guastatore, the revised troubleshooting focus for 3rd gear not engaging on a brand-new GX T-Type build should be:

• UDH direct mount alignment - there is no replaceable hanger with T-Type. The derailleur mounts directly to the frame's UDH interface. So if something is off here, you're looking at the frame's UDH socket itself or the axle seating correctly - check that the direct mount interface is fully and correctly seated. Check this first.

• AXS app micro-adjust - use the trim function in the app to nudge the derailleur position. This is your "barrel adjuster" equivalent. • Chain length - still valid. 120 links may be off for the specific frame/cassette combination.

• T-Type cassette - as @Paulquattro implies, this system requires a dedicated T-Type cassette. A standard Eagle cassette won't index correctly with the Flattop chain and Transmission derailleur.

Thanks for keeping me honest, @Paulquattro.

EDIT: Corrected the UDH hanger point - T-Type uses direct mount to the frame's UDH interface, meaning there is no separate replaceable hanger to check or bend. Troubleshooting should focus on the direct mount interface and axle seating instead. Thanks @Paulquattro for the heads up.

 

[Paulquattro]

• UDH hanger alignment - if the hanger is even slightly bent or not fully seated, it throws off the whole indexing system. Check this first.

Unless the bike frame or axle is bent which is doubtful there is no hanger as the T-Type is direct mount .

 

[Greg Watts]

Unless the bike frame or axle is bent which is doubtful there is no hanger as the T-Type is direct mount .

@Paulquattro - you're right, and that's already corrected in the post above. I'd edited it to say "direct mount interface" rather than "hanger" but clearly didn't scrub it fully. Fair point - no hanger exists, so there's nothing to check or bend. The only structural concern would be the frame's UDH socket itself or the axle seating, exactly as you said.

Cheers for keeping it clean. Appreciated as always.

 

[RickBullotta]

Hi Greg, could you help me set up the GX T-Type because I'm having trouble with the third gear? Frame size: CEF69

This is a well known and well documented issue (third gear shifting issues on SRAM transmission). Google around and you'll find hundreds of discussions and what worked/didn't work for others. In rare cases it's a manufacturing defect, but more often than not it's just a setup issue (chain length, chainline, derailleur setup/alignment/torque, microshift adjustment, bent tooth or damaged chain, etc)