I always intended for my gravel bicycle to run a mullet drivetrain, but due to the budget constrains I had to settle on Shimano gravel-specific mechanical rear derailleur and road shifters. Time for an upgrade.
So, what’s a mullet drivetrain? It’s a hybrid that pairs drop-bar shifters with a wide-range mountain bike rear derailleur, usually set up 1x.
I’d probably stick with what I’ve got, but a few rainy-muddy rides at Baltic sea trashed my cable actuated setup. One day, the cable housing got so gunked up it just stopped working and the only way to fix it would be to redo the cabling. That’s a bit of a nightmare with the internally routed handlebars, because there was continuous housing from the shifter, through the bars and frame. Maybe it was time to upgrade to wireless shifting?
I’m a long term Shimano user, so naturally I started looking candidly at their Di2 solution. I knew it is possible to run electronic MTB rear derailleur with road shifters. But it quickly became apparent to me, that this route would be just to much of a hassle. First of all, it was really difficult to wrap my head around what’s really required to run Di2. Shimano is famous for expensive bits and pieces and their electronic groupset is just electronic, not wireless. I’m not sure my frame is capable of routing Di2 wires. But that’s not all. I was also utterly lost in the search for information about junction boxes, seatpost batteries, special tools, connectors.
I was familiar with SRAM and their double tap technology and their annoying grip shifter on my kid’s bike. But since then this american company created their AXS system. It’s completely wireless. Battery is on the derailleur, shifters use coin-shaped CR2032, so there’s no need for any cables whatsoever. After short (and lost) battle with my conscience (because it’s freakin’ expensive!) a delivery has been made to my home address.
With my desire to run the real mullet drivetrain, I decided to go with the SRAM Eagle GX AXS rear derailleur paired with SRAM Force eTap AXS shifters, but with mechanical brakes. I’m satisfied with my TRP’s Spyre cable actuated callipers and not really willing to play with the hydraulics. Since the rear mech is an MTB one, I can now use their hilariously huge cassette SRAM NX 11-50t. The entire system is 12 speed, so it’s also an upgrade in those terms.
Let’s put it on the bike!
The process of putting new toys on the bicycle was astonishingly easy. There are no cables to run from the shifter to the derailleur so you just put them on and that’s it. Of course you have to pair them together, but that’s a no-brainer. In fact, the hardest part of the entire process was the removal of old derailleur cable and housing, because I had to yank it out from the frame and handlebars (it was really tight fit). I also had to reroute the wires for the rear light, so they now run along the brake housing. I also replaced my chinese oval chainring with another cheap one, but slightly bigger.
I was pretty much done with everything within 1,5 hours. Fortunately, I could reuse brake cable housings, because the one in the box was way to short (I suppose it was for a road bike). The setup of shifters and derailleur was very intuitive and straightforward, as well as pairing the groupset with SRAM AXS mobile app.
There is no cumbersome cable trickery and barrel adjusters to align the derailleur with the cogs. It comes down to setting up limit screws and B screw to position it correctly. Then you can „trim” it with the shifters or with the app using micro adjustment option. Despite my derailleur hanger being slightly bent, I was able to work it out in minutes. TA-DAH!
New ride quality!
I’ve been using my previous GRX setup using something called „goat link” which makes use of bigger cassettes possible. This rendered the derailleur far from perfect. The „clutch” was heavy on the shifting and entire thing has been still a bit noisy on the bumps. Eagle GX has no mechanical clutch, using hydraulics magic which they market as Orbit technology. You don’t have to enable it, it’s always working and despite the reviews claiming it’s rattling, I have observed otherwise. It’s clean and quiet. The shifting is spot on and very rapid and I couldn’t be more happy with it.
I’m still considering ditching my old, outdated road bike and have some new exciting projects in mind, but right now, of one thing I’m certain. My next bike will be also using SRAM.