Rebuilding your AXS Derailleur with Madrone

When I met Aaron Bland, founder of Madrone, and listened to him talk about his kit, I knew I was the perfect candidate. I had recently robbed a rear derailleur off a test bike because the GX AXS version on my personal bike was shifting inconsistently. Sometimes it was fine, other times it would hesitate or move two cogs for one shift, and very rarely it would drop down the cassette with an alarming cracking sound that always stopped me in my tracks. It didn't appear to be bent and I'd checked the hanger alignment and B-tension to no avail. It was just sitting there on a shelf, destined to become a donor mech. Or a doorstop.

SRAM offers a few replacement parts for their derailleurs but they don't go beyond limit screws and cage components. If you want to tangle with pivots or parallelogram links, you'll have to look elsewhere. And for now, the best place to looks seems to be Madrone.

Much of Aaron's engineering background is in battery technology. He worked in tech helping Amazon with their drone fleet and for other companies, providing portable electricity solutions. You might think his entry into the bike world would have an electric edge as well but Aaron's all about mechanical for his mountain bikes.

Aaron, and his company Madrone, manufacture kits and tools to replace 8 bushings, 3 pins, 2 links, 4 shims, 3 washers and 3 snap rings needed to rebuild your parallelogram.* Madrone also makes a replacement cage and jockey wheels, and he sent me both sets of parts.

*give or take

Also included in Madrone's kit are all the tools required to do the job. It's really a very complete kit but you'll also need some basic tools like hex keys, a hammer and needlenose pliers (a good set) but also a 5/32 punch, which you may not have lying around. I prefer to buy local when possible but I could only find expensive complete punch sets nearby. Instead I plugged my nose and bought one on Amazon. A mechanic's pick will come in handy as well but a sharpened spoke with one end twisted into a handle will work in a pinch.

The 3D-printed tools are really the highlight of this kit and I found myself amazed at Aaron's ingenuity. The coolest one is the "Torsion spring tool," which is a clamp that helps you preload and install the return spring, but each little green doodad is worthy of admiration.

At a certain point, I realized that I had skipped a step and had to go back. Rewinding Aaron's video was critical because I could not see any conceivable way of accomplishing it on my own. I went back hoping I hadn't passed a point of no return. I eventually realized the step I’d skipped was to remove the servo. The structure around the servo is apparently sometimes sticky but that came off easily. In the video the servo itself came out very easily, but when I went to take it out, it didn’t move at all, causing me some concern. Eventually, a good yank got it done (that’s what someone said).

As I was putting the spring back in using Madrone’s incredible tool, I chose the wrong bushing (4mm vs 5mm) and had to extract it making for another rewind. Then, while I was installing the long bolt that holds the two parts of the inner link together, I was simultaneously trying to encourage my kids, who are 18 and 21, to finally do the dishes after three days of promises, and I missed the step that included sliding the sleeve in place. As a result there was no stop while I was tightening the bolt and I threaded it well past the point its intended endpoint. 

Those were mere hiccups but then things went completely sideways. I wasn't sure what my error was. Everything looked fine but the derailleur didn’t shift properly when moving to a lower gear when I hit the AXS button. 

After clicking and double clicking the AXS button several times, I noticed the mechanism would bind when the derailleur started to move further inboard. There was some damage on the plastic knuckle cover that would lift and interfere with the movement of the outer link plate as it rotates around the joint. It actually seemed that the shape of the Madrone link plate made the problem slightly worse since the cutout where the plate meets the knuckle is slightly more rounded.  

*Double clicking moves the derailleur in the opposite direction than a single click - vital information when your shifter gets smashed or your coin cell dies

I used Aaron’s video to remove two of the pins I had already installed, in order to free the knuckle and went to find some epoxy.* The wear on the plastic plate indicated that it had been restricting the servos for some time. It’s always good when you have to put your 390 USD derailleur into a vice and glue it together.  I also took a file to Aaron’s beautifully machined links to provide a little extra insurance that this interference would not return. 

*I am a big fan of Weld Bond epoxy. It is incredibly strong but what I appreciate most is that, because it needs to be mixed to harden, the two elements never dry out. There's nothing worse than reaching for your glue only to find it fossilized.

The process of rotating the cover, compromised the fit further, necessitating more epoxy and more rotating. Once all the sticky stuff was in place, I tightly wrapped the knuckle with tape and then found the right angle in the vice to apply pressure to the problematic plastic.

Five or so hours later, when JB Weld is set but not cured (which takes 15-24hrs) I retrieved the piece and began putting everything back together. I had some more disassembly to do because I need some of the already installed parts to use in the Torsion Spring Tool.

An element of this kit that I find particularly ingenious is the use of parts from the finished product as components of tools on the way to line. In this case these parts were used immediately after they were needed which meant I had to undo even more of my work to get back to where I was when the problem arose. Considering it was enjoyable the first time this was no real hardship.

Once it was time to put the cage together, Aaron helpfully laid out all the tools required in his video. He went through them carefully and when he got to the lock washers, he said "at least two of these small lock washers." I looked down, and I only had one and began to panic. ”At least two?” Does that mean three would be better and I only have one? 

Just like when it happened with Lego, I assumed I was the problem. Maybe the tiny washer was stuck in one of the tiny manila envelopes I’d already recycled? Where was I going to find a 4mm lock washer? Thankfully it had just slid into a seam in one of the small boxes and all was right in the world. At least for a moment. 

And in fact the rest went together quite smoothly. Pre-loading the spring was a little nerve wracking, but nothing exploded. Even more impressively, in the end it looked like a derailleur.

Speaking of Lego, that's a good approximation of what this task feels like. You simply follow the instructions and eventually find you have built something cool. And Aaron's video is great. It's a bit like having a young Mr. Rogers teach you something. He's very encouraging and clear and very sincere. Just like in person, it's nice to hang out with him. And the video is very easy to follow.

My favourite thing about AXS derailleurs is how easy they are to install on bikes that have challenging internal cable routing. It literally takes a few minutes and you are done. I re-checked the hanger and the B screw and got everything tickety-boo. All I had time for was a little spin around the neighbourhood but the results were encouraging. My chain and cassette are a little long in the tooth and it took a little while to dial in the shifting with the micro adjust feature but then it was very sweet indeed.

As it turns out, the problem with my derailleur was self inflicted (or maybe son inflicted) and the issue wasn't solved by the Madrone kit. But I wouldn't have been able to fix the problem without some means to disassemble the links to get access to the knuckle. I could have rebuilt it with the SRAM parts and likely had a similar result, although a few of the bushings in the original links were a little dodgy.*

*Another company, Leap Components, makes a kit you can use to replace the existing bushings and reuse most of the SRAM parts. They have a how to video as well.

In some ways this is a great time to be alive. The fact that a sole proprietor can put together a repair kit to rebuild a product made by a multi-national mega corporation, including building the tools and parts in a small shop, is fucking brilliant. If your SRAM derailleur, AXS or cable activated, is acting up, I can unreservedly recommend this kit in terms of execution and quality. Obviously I can't yet talk about reliability but I have no reason to doubt the longevity of these links, pins or bushings.

The AXS Link Kit with tools costs 135 USD or 110 USD without tools

The Mechanical Link Kit with tools costs 119 USD or 95 USD without tools

The Hanger Kit costs (AXS or mechanical) 79 USD or 128 USD with jockey wheels

Check out Madrone Cycles for more info.