Troubleshooting T-Type gears: Correctly setting the Sram Eagle transmission

The new Sram transmission gear system with direct mount has entered the market with a clear promise: set it up once, never have problems again! With this technology, the setup should be particularly simple and jumping gears should be a thing of the past. Nevertheless, problems can still occur with the T-Type shifting system, as Sram calls the new standard.

An accumulation of incorrectly adjusted gears on our test bikes shows: How the setup of the still young Transmission works has not been understood everywhere. We take this as an opportunity to show you step by step how to set up a Sram Transmission drivetrain and how you can avoid shifting problems with the new T-Type system.

Experienced screwdrivers in particular have to rethink their approach with a transmission circuit. Without operating instructions and new basic knowledge, even professionals can't get any further. "You have to learn how to adjust the gears from scratch," says Sram man Moritz Dittmar about adjusting the transmission gears.

And that is precisely the crux of the matter. Because even with years of accumulated experience in shifting set-up, there is only so much you can do with the new system. Instead, you have to adhere strictly to clearly defined specifications.

Full Mount - these are the differences

In terms of design, there are fundamental differences between aThe design of the so-called "full-mount" rear derailleur of the new Transmission series differs fundamentally from that of a classic rear derailleur.

Instead of a derailleur hanger, the rear derailleur is attached directly to the frame. There is a standardised interface for this (UDH = Universal Derailleur Hanger). This means that the position of the rear derailleur and cassette should be exactly the same on every bike. The upper and lower limit stops do not need to be adjusted on transmission derailleurs, but are almost automatically perfectly positioned.

In fact, in the last two years since the market launch of the new technology, we haven't had a single problem with the chain being pushed off the top or bottom of the sprocket set on countless test bikes. Mission accomplished!

The second fundamental difference: The wrap of the rear derailleur, i.e. how far the upper derailleur pulley is from the cassette, is not infinitely adjustable via a screw. This adjustment is virtually automated during assembly.

However, only if you follow the instructions exactly. In practice, problems can arise if some basic rules are not observed or the main screw of the rear derailleur loosens. More on this below.

Step-by-step instructions: Setting the transmission gearstick

1. you can't do without it: know your setting parameters!

The basis for every setting of a Sram transmission shifting system are certain basic parameters. These depend on the respective bike model and must be determined before setup. Sram has a database (app or website) for this purpose, in which almost all available models on the market are stored. Somewhat confusingly, the database is called the "Full Mount Chain Length Guide". But there is more to it than just the correct chain length.

>> To the Sram database: https://axs.sram.com/guides/fullmount/chain/calculator

Based on the bike model, frame size and chainring size, the calculator spits out the following parameters, which are essential for the correct setting of every transmission gear:

• Setup key position A or B
• Chain length
• Setup sprocket

ATTENTION: If you install a different chainring size or change the geometry using a flipchip, this may mean that the parameters change. You will then have to adjust them and realign the rear derailleur.

2. align the transmission gearbox

Only when these parameters are clear and correctly prepared can you attach or correctly align the rear derailleur. To do this, first shift to the setup sprocket. The 21st sprocket (7th from the top) is marked in red and is used as the setup gear in the vast majority of cases. But beware: In exceptional cases, you will need the one larger 24 mm sprocket! You can find out whether this is the case with your bike in the "Full Mount Chain Length Guide" in the AXS app or on the Sram website as described above.

In the next step, first loosen the rear wheel axle by exactly one turn and then open the main fixing screw of the rear derailleur until it is hanging loose. The cage must then be locked in the setup position.

The rear derailleur is then pulled backwards on the cage until the chain is tensioned. The main fixing screw of the rear derailleur must be tightened in this position.

A large torque spanner is required for the next step. It is essential that the screw is tightened to 35 Newton metres for the gearstick to function correctly in the long term. For anyone without a torque spanner: that's a lot! Because if the clamp loosens, the rear derailleur slips and performance is ruined. The cage then often touches the cassette when shifting, which can even paralyse the bike completely.

Finally, tighten the rear wheel axle according to the manufacturer's instructions and release the gear cage from the setup position.

Tip: The necessary torque cannot be applied with a mini-tool on tour. If you have problems on the road, you should definitely repeat the correct adjustment at home (or in the workshop) with a proper tool!

2.1 Quick run Align transmission gearbox

1. Engage the correct setup gear
2. Loosen the rear wheel axle by one full turn
3. Loosen the main fixing screw of the rear derailleur
4. Lock the cage in the setup position
5. Pull the loose rear derailleur backwards by the cage and tighten the main fastening screw
6. Tighten the main fastening screw to 35 Nm
7. Tighten rear wheel axle
8. Release cage from setup position

If you want to check whether the setting is right for you, there is another trick in addition to the visual check of the markings (see picture). Shift into your appropriate setting gear and bring the cage into the setup position. This should work in the setting gear without moving the cage too much. If you have to push the cage forwards significantly to do this, something is probably wrong.

Tip: If the derailleur suddenly causes problems, it makes sense to carry out steps 1 to 8 to ensure that the rear derailleur is perfectly positioned. If you have changed the chainring size or geometry settings, it is possible that the setting parameters for your derailleur have changed! Check the database and adjust if necessary.

3. micro adjust: fine tuning for perfect shifting

What the tension is for classic derailleurs, the Micro Adjust is for Sram's electric AXS. This means that the rear derailleur can be fine-tuned inwards or outwards in 0.2 millimetre increments. If one or more gears make noise or the rear derailleur does not move the chain up or down fast enough, the derailleur is not positioned exactly under the respective sprocket. Accordingly, the rear derailleur must be positioned further inwards or outwards.

Work your way up to the ideal position in the gear that is causing problems. The position in which the chain runs smoothly without rattling is the right one. Important to know: The fine adjustment always applies to all gears simultaneously.

It is helpful to take a look at the app during this procedure. Here you can immediately see which adjustment position you are in. There are 14 micro-adjust positions, with position 7 marking the neutral centre. If the shifting is fully adjusted, it makes sense to go back to the neutral position and work your way up from here. Fine adjustment is possible completely without the app and even works while riding. However, a look at the app helps to clearly visualise the setting and changes.

Tip: If Micro Adjust is in an extreme position (1 or 14), this is an indication of an incorrect setting. As a rule, Micro Adjust should be close to the neutral centre position.

Caution: On full-suspension bikes, the rear derailleur position changes via the suspension travel of the rear triangle. This can also affect the shifting performance. The final and definitive fine adjustment must therefore be made while riding. It may not be possible to adjust the gears perfectly on the assembly stand. So: Initial adjustment in the workshop and then make any necessary improvements if problems occur while riding.

Tips & Tricks: Troubleshooting Sram Transmission gears

Is my rear derailleur bent?

When looking at a transmission rear derailleur from behind, you could easily become suspicious. This is because the cage is not in line with the sprockets. But don't worry: the cage is not bent, but is designed asymmetrically ex works. Sram calls it an "inline cage". In fact, there were no cases in our tests where shifting problems were caused by a bent cage. You might get the impression that the "innate tilted position" makes it more difficult to detect any defects. However, a visual inspection is not always helpful, even with classic derailleurs. Sram asserts that the cage is very robust. If there really was a defect, it could be identified visually without any doubt. By the way: The cage can be replaced without tools and is available as a single part. In carbon or aluminium.

The gears work perfectly on the assembly stand, but they don't sit perfectly when riding. How can this be?

Ideally, you would set the gears in SAG, i.e. with the rear suspension slightly compressed. This is because the position between the rear derailleur and cassette can change with the spring movement. This can have an influence on the shifting performance. The final and definitive fine adjustment must therefore be made while riding. Particularly on steep climbs off-road, the bike can sink deeper into the shock stroke, which can exacerbate the problems.

My rear derailleur is not responding to the commands from the gear lever. What can I do?

The rear derailleur and shift lever must be linked so that both components of the Sram wireless shifting system can communicate with each other. To do this, the AXS function button on the rear derailleur must be pressed until it flashes green. Then press and hold the function button on the shift lever until it starts flashing green rapidly. The pairing process is then completed by pressing the button on the rear derailleur again until the green LED stops flashing.

The gear lever or rear derailleur no longer move at all. What is going on?

Probably a classic case of an empty battery. The AXS battery is located on the rear derailleur and needs to be charged in a separate charger. The levers, aka pod controllers, are fitted with button cells (CR2032, not rechargeable batteries!). The LEDs on the rear derailleur and shifters provide information about the charge status. Sram specifies the following runtimes:

Gear lever: Green = 3 to 12 months of use remain; Red = 1 to 3 months of use remain; Flashing red = less than 1 month of use remaining

Rear derailleur: Green = 5 to 25 hours of use remain; Red = 1 to 5 hours of use remain; Flashing red = less than 1.5 hours of use remain

A tip for transport of an (e-)mountain bike with Sram AXS drivetrain: As the drivetrain reacts to vibrations, is actively shifted and consumes power accordingly, the battery should be removed from the drivetrain when travelling. For this purpose, Sram supplies red protective caps both for the slot on the derailleur and for the battery itself.