Installing a SRAM AXS T-Type Derailleur

This article was motivated by an oversight on my part. Last week when I posted a how-to on swapping a T-Type cage, I left out the most important part. The best way to do that job is to remove your rear derailleur, which means you are going to have to re-install and set it up again, and in that article I failed to provide that info. If you are just swapping a cage, there are fewer steps than I have listed below. I wanted to provide info for riders starting from scratch as well. If you scroll down you'll be able to determine when you need to start.

In the last five years or so I have really leaned into the DIY lifestyle beyond bikes. Usually the best source of information about how to do something I haven't done before is YouTube. Sometimes this works great but for multi-step procedures, I find it awkward. Often I need to go back and watch something again but I'm wearing gloves so I have to take them off and then an ad comes up and I can't find the spot I'm looking for so I skip an important step and screw everything up. So it's not the best.

For a task like this, with critical steps that must be done in a particular order, I prefer to have written instructions that don't scroll away from me the way a video does. Hopefully some of you will find this helpful.

T-Type isn't Like the Others

You'll need to forget most of what you know about installing a cable actuated drivetrain, and even a conventional AXS derailleur. Transmission mechs don't have limit or B-tension screws and obviously they don't have cables. In fact, you could easily set up T-Type without having a shifter in the room.

I'm not going to cover pairing your shifter and derailleur here but it's as easy as pressing the AXS button on your derailleur until the indicator light starts to blink, doing the same on your shifter, and waiting a moment until their union is complete. True love.

Before you start putting things on your bike, if you are doing this from scratch that is, there are three things you need to determine; chain length, Setup Cog, and Setup Key position. If that last one sounds like some obscure Tesla gizmo, don't worry, you are not alone.

Back in 2012, SRAM introduced a worthy and useful innovation and they called it Cage Lock. If you have used a SRAM derailleur since that time, you are likely familiar with it. On all SRAM derailleurs since, you can swing your derailleur cage forward past a little plunger that can be deployed to disengage the cage return spring and keep your cage out of the way. This is great for removing and replacing your rear wheel, installing a chain, cleaning your bike, replacing a jockey wheel or any task where your springy thingy used to get in the way. That is Cage Lock.

For T-Type, this now serves another function. It still works in the same way as Cage Lock but there is a new position called Set Up Mode. Instead of rotating your cage all the way forward, you rotate it to the point where there is a elbow in the inside arm of your cage. The wee plunger that used to be called Cage Lock now has two names; Cage Mode Button and Setup Key. It's called the Cage Mode button because it now can be put in Open mode, just like the Cage Lock function of other SRAM derailleurs, but also in Setup Mode. The reason it's also called the Setup Key is because it has two positions, A and B. Swapping involves popping out the plunger and turning it 180º, either with your bare hands or a small screwdriver.

Every bike that is compatible with UDH will require the Setup Key to be in one of those two modes. You can find out which mode works for your frame by using AXS web or using the AXS app. If you perform the set up in the wrong mode, your results may be unsatisfactory.* Switching the mode is as easy as pulling out the plunger, rotating it 180º and then reinserting it: no tools necessary.

*SRAM says you might even "damage your derail-your (as the voice in the SRAM how to videos says) or your bicycle."

Another variable is the Setup Cog. There is a red disc on T-Type cassettes indicating the 21t cog, which works for some frames but others require the 24t cog. When Transmission first arrived I don't recall this distinction and in my memory, every bike was set up using the red-marked 21t. How do you find out which cog your bike needs? This is also determined using AXS web or the AXS app.

Chain length is the third variable that is critical to setting up your SRAM Transmission and, impressively, you can look that up in either AXS web or the AXS app as well. It will tell you exactly how many links you need for your bike. If your frame is not listed, you are going to have to collect a little info and go through the procedure; measuring your chain stay, declaring whether your ride is full squish or hardtail, with an idler pulley or not, and then hit enter. SRAM's AI spits out an answer that also tells you whether your bike should be set up sagged or un-sagged.

If your bike is listed, all you need to do is count links and shorten as necessary. SRAM tells us the full length chain is 126 links so you only need to count down instead of starting with 2.*

*Surprisingly, chain links come in pairs so always count by twos

Tools Required

• T25 Torx
• 8mm hex head wrench
• 5 or 6mm hex for rear axle
• chain breaker (if you need to shorten your chain)
• small flat head screwdriver - or anything with sharp, flat point to swap the Setup Key
• cassette tool and everything else you need to install an entire drivetrain, if you are also swapping cranks or chainring

Hang the Parts

Now that you have determined your Setup Cog, Setup Key and chain length, it's time to slap everything into place.

First remove your rear wheel and then, if you have a UDH hanger in the frame, you'll need to remove it. Be aware these are reverse-threaded so you'll need to turn the bolt clockwise to loosen it.

Once that is gone you can install the T-Type derailleur.

Remove the Full Mount bolt from the derailleur and the bushing frame insert. This is a simple plastic bushing that sits between the bolt and your frame.

Install the Derailleur

1. Slide the red bushing into the frame from the outside until the flange is flush, black side out. NOTE - do not apply any grease to the bushing or the frame.
2. Before you position the derailleur, apply a small amount of grease to the threads and inner flange of the Full Mount Bolt.
3. Make sure the knurled ring on the inside of the full mount is fully rotated clockwise.
4. Position the derailleur below the bike and then slide it upward so the full mount holes align with the axle hole.
5. Insert the bolt and tighten it (clockwise) until snug.
6. Loosen the bolt (counterclockwise) by one full turn.
7. Rotate the derailleur cage forward until it completely clears the Cage Mode Button and depress the button so the cage is in Open Mode.
8. Swap the Setup Key to that specified for your bike, either A or B

Install the Wheel

1. Grease the axle threads
2. Install as you normally would but only tighten the axle until snug.
3. Loosen the axle by one full turn.

Mount the Chain

By this point you should have determined your chain length and shortened the chain to that length.* You'll also need to put the Setup Key into A or B, depending on the recommendation for your bike , and know if you need Setup Cog 21 or 24.

*Some high pivot plus idler bikes will require more than 126 links and thus two chains.

1. Advance the derailleur to align the appropriate Setup Cog using AXS button on the derailleur. One click of the button moves the cage outward and a double click moves it inward. I only recently learned that second trick.
2. Thread the chain through the derailleur, being careful to align it inside the tab in the cage. Also make sure the flat top is facing away from the cassette.
3. Pull the chain all the way through, over the Setup Cog and then over the chainring so both ends hang downward toward the floor.
4. Use the Powerlock to join the chain, ensuring the flat top aligns with the rest of the chain. Make sure it is snapped together.
5. Push the cage forward until the Cage Mode button releases.
6. Put the cage in Setup Mode (rotate the cage forward again but only until the elbow in the inner part of the cage clears the button and then release.
7. Rotate the chain so that the power link is on top, above the chainstay and between the cassette and the chainring. Engage the rear brake and push the pedal or crank down firmly to ensure the Powerlock is indeed locked. You can also use chain pliers for this if you have them.

Lock Things Down

This is a good time to verify that you've got your derailleur in Setup Mode, you are on the correct Setup Cog and Setup Key and that your bike is sagged or un-sagged, depending on the recommendation for your bike from SRAM.

1. Pull back on the lower pulley of the derailleur to remove any slack from the chain.
2. Rotate the cranks a few times to make sure everything is aligned properly.
3. Continue to pull back on the lower pulley while tightening the mount bolt. If there is slack in the chain after this, repeat these steps.
4. There is a raised indicator line on the knurled ring (the metal piece opposite from the mount bolt) and another on the Full Mount that is white. These should be aligned at this point. If they are not, repeat the steps above.
5. Tighten the mount bolt, ideally to 35m. If you have a tool that will do that. I couldn't find an 8mm hex that would mate with my 1/2 inch drive torque wrench I use when swapping rims from summer to winter so I gave my best guess.

Using Micro Adjust

At this point you can check your shifting. Don't be alarmed if, while still on the stand, it isn't silky smooth. While T-Type shifts very well under load, it shifts worse when there is no load. At the same time, if it won't make a shift or if it is trying to go up or down the cassette when it should be staying in one cog, you may need to make some micro adjustments, either using your shifter's AXS button or with the app.* Doing it from the shifter is so easy I do it from the saddle if I have banged my cage and messed things up a little during a ride. All I need to do is reach over with my left hand and depress the AXS button, then I choose the button that shifts up or down the cassette with my right thumb, depending on which way I need to go. Every click while holding the AXS button moves the cage 0.2mm. It's a truly great AXS feature.

*I only use the AXS button method because it's so convenient

Micro Adjust Steps

1. 1) Determine which direction your derailleur needs to go by either eyeballing it or paying attention to which shifts are problematic. If your derailleur isn't moving up the cassette well, use the button you've chosen to shift to a larger cog (lower gear). If you can see that the chain isn't vertically aligned with the cog it's in, determine which direction it needs to go and use that button.
2. Depress the AXS button and then use the shift button that will move the chain in the direction you need to go, ether inboard or outboard.
3. Attempt some up and down shifts to see how it's working. If the chain is hesitating to make the shift you've indicated, micro adjust in that direction. If the chain is shifting two cogs when you clicked once, or trying to shift beyond the direction you've indicated, you need to micro adjust in the opposite direction.

This is often a process of trial and error. If you can't nail down your shifting in this way, it may be that you need to start the process again, check your chain length, Setup Cog or Setup Mode. If your derailleur isn't new, it's possible your cage is bent. This isn't as easy to determine with T-Type because the pulleys are offset by design to keep the lower pulley more accurately aligned with the chainring through the entire cassette, so straight isn't straight.

There's nothing like the feeling of a smooth running machine that you had a hand in putting together, and T-Type makes this pretty easy, as long as you do a little homework using SRAM's tools, either online or with the app.

The entire value proposition of T-Type is yet to be determined, but if you're budget is tight, derailleurs that are pulled by a cable are a great place to save cash. It seems the T-Type chains and cassettes have very good longevity, based on early returns, and for the most part the derailleur seems to take a beating as advertised and keep shifting smoothly, for most people. An exception is for those who smack their hanger one too many times, as I did. Luckily this is a cheap and easy fix.

Even if the chains and cassettes last twice as long that doesn't scratch the surface. You'd have to smash a lot of cable-actuated XO derailleurs before you begin to approach the cost of an entire GX Type drivetrain. And that XO would work almost as well in all but the worst situations, and infinitely better than AXS with a dead battery in the shifter or derailleur.

If you prefer the analog simplicity of cables, I won't try to talk you out of it. Aside from tangling with challenging internal cable routing for the rear derailleur, I am very close to as happy using that heirloom technology. I prefer the shifting feel of Shimano but I'm also fond of the durability and longevity of SRAM's derailleurs, chains and cassettes. Overall I'd say we're lucky to have two solid choices in such an important category.

If you like to be able to shift even when you shouldn't be able to, (finding yourself on a shitty surprise incline in the wrong gear on a long trail chasing your buddies), and you like gizmos and innovation and don't mind batteries, T-Type is pretty cool.