Thinking about Sram GX AXS with shimano cassette? SRAMano. Shimam. Frankentrain. Mixed drivetrains. Whatever you call it, does it work? Let’s talk about that.
This is one of those weird questions we get asked all the time at the shop and we never really have a clear answer. Can I run a Sram chain on my Shimano drivetrain? What about shifters and derailleurs? Can I put AXS on my bike that already has Shimano stuff on it? If you ask each manufacturer, the answer is probably no. But, we are going to find out what actually works and what doesn’t. In a perfect world, I’d test every last combination, but I’m a lone individual with a budget and timeline — I’d like to finish the test sometime this year (Exhibit A). I did my very best to cover as many combinations as possible. If there’s one I didn’t test that you really want to see, go out and test it. Let me know what happens.
For the majority of the test, I took my perfectly fine Shimano XTR shifter and derailleur off my Orbea Rise. I swapped it out for the new Sram GX AXS wireless bits. I left the Shimano XTR cassette and e*thirteen cranks. I used AXS partly because I think this will be a common upgrade as the AXS tech has trickled down into a more affordable range. And partly because I didn’t want to deal with routing cables on an eMTB. I have a weird medical condition where I’d rather ride my bike than fiddle with it.
All the drivetrains for this test are 12-speed systems. I’m not trying to mix and match different speeds here. That just sounds like a headache. I’m also not going to test every last brand possible (again, see Exhibit A). This is strictly going to cover the big two.
Mixed Drivetrains Results
Mixed chains – Go — Mostly.
The most common scenario we get asked about is mixed chains. Can you put a Shimano chain on a Sram drivetrain and vice versa? Yes and no. As long as the speeds match, it theoretically should work. In the real world, we have noticed that Shimano chains on Sram cassettes and chainrings tend to not line up with the teeth on the cogs perfectly. It seems like the culprit is the inner width on Sram and Shimano chains aren’t the same. I measured with a set of calipers, but mine isn’t accurate enough to measure the minuscule difference between them. So, you’re going to get some real anecdotal pseudoscience here. When I lock the calipers after measuring on a Sram chain, I’m not able to fit that between the plates on a Shimano chain. That said, we’ve had some OK success running Shimano chains on Sram drivetrains. In fact, I’ve been running a Shimano 12 speed chain on a Sram NX cassette for over six months now with no issues. The opposite, Sram chain on a Shimano cassette, seems to work better. So can you mix and match chains? It works, but it’s generally best to match the chain to the cassette and chainring.
Mixed shifter and derailleur – No Go.
Can’t fight physics on this one. A Shimano shifter doesn’t play well with a Sram derailleur and vice versa. Basically what is happening here is that a shifter moves the cable a certain amount which causes the derailleur to shift a gear. The problem is that Sram and Shimano shifter/derailleurs are designed around different amounts of cable movement. I’m 100% making up these numbers, but let’s say a Sram shifter moves the cable 2mm. With a 2mm cable pull, the derailleur moves enough to shift one gear. Now, let’s say Shimano pulls the cable 1mm to move the derailleur one gear. See the problem? You throw a Sram shifter on a Shimano drivetrain and it’s pulling the cable too much. The same problem applies to the opposite combination. Some gears might actually work and line up, but most are going to be way off. There might be some major hacks to get around this but I’d say they aren’t really worth the time or money you’d put in for less than optimal shifting.
Same shifter and derailleur with mixed cassette – Go.
Alright, this is where things get interesting. Particularly, when you consider that you can get wireless Sram AXS shifting on your Shimano drivetrain. I bought a Sram GX AXS upgrade kit with the intent of running it on my Orbea Rise with a Shimano XTR drivetrain. I didn’t want to swap out the entire drivetrain for a couple of reasons – the first being cost. Cranks and cassettes are the most expensive parts of any drivetrain. If you can avoid replacing those it’s going to save you a lot of money. Second, the wheels on my Rise are meant to be used with a Shimano Micro Spline cassette. If I had switched to a Sram cassette, I would have needed to replace my freehub body — that gets expensive. Lastly, I just wanted to see if the frankentrain was possible — so here we are.
sram gx axs with shimano cassette test
The swap went perfectly. I was able to set up the GX AXS shifter and derailleur on my bike without any issues. I pulled the old parts off and replaced them with new ones. It shifted perfectly in the repair stand. Repair stand shifting rarely reflects real-world, less-than-optimal conditions, however. So some real-world testing was needed.
Despite my best efforts to make conditions as bad as possible, the testing went pretty much as well as the repair stand shifting. I shifted under load, while standing, in the snow, after riding through a creek, with a dirty/icy chain — you get the point. Ultimately, I was unable to get the thing to make a mistake. Every shift was perfect and fast. I didn’t break any chains, and I didn’t have any missed shifts. The only downside I experienced was the noise. The shifts weren’t quiet, especially under load. The chain didn’t quietly glide into place on the next cog. It sort of slammed its way in there with an audible pop. I’m curious to see if I’d experience more broken chains after riding this for an entire season. I also started hearing a grinding/scraping sound midway through my ride. Turns out that wasn’t the fault of the mixed components at all. It was simply snow and ice building up in the chain guide — duh.
Mixed Drivetrains Conclusion
To say I’m pleased with the results of the frankentrain would be an understatement. Considering these parts were never designed to play well together, the Sram GX AXS shifter and derailleur work perfectly on the Shimano XTR cassette. I really don’t see any drawbacks to trying this upgrade. So if you want wireless shifting but you already have a Shimano drivetrain, I’d say “send it.”
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