SRAM AXS cassette/derailleur compatibility

I’m trying to figure out which cassettes I can use with which AXS derailleurs (of course SRAM doesn’t make this easy). Specifically I’m trying to determine if a new GX Eagle AXS derailleur will properly shift a force/rival 10-36 or 10-33 cassette. I feel like it will not, that the derailleur will somehow be too big for that cassette, but I don’t really know. Anyone have any idea?

Thanks

Those it will not, since these are road AXS cassettes with the need for the flattop chain while the Eagle AXS RD needs Sram’s “normal” 12x chain.

But - 3T writes in their blog that they have successfully tested:

  • “* Rotor’s 12-speed 11-46T cassette. This is a great hack of the system with a 418% range, so basically the same as that magical 420%. And with an extra cog so the steps are smaller. It shifts flawlessly with a SRAM Eagle AXS rear derailleur and chain.”

  • “* Rotor’s 12-speed 11-39T cassette. Yes, this one also works with the Eagle AXS rear derailleur and Eagle chain! The range is small, but bigger than the 10-33T (355% vs 330%). It’s great for riders (I happens to be one) who don’t care about their top gear because they are a relaxed descender. You can use this cassette together with a small chainring (maybe 36T, depending on your strength and terrain) and enjoy very nice, small steps between the gears.”

See here: https://blog.3t.bike/2019/09/12028/gravel-tech-hacking-sram-axs-drivetrains/

So it seems that the eagle AXS RD can shift down to a 39 cog. So I guess Shimano’s 10-45 12x cassette might also work.

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Oh that is great, thank you. I’m trying to determine my ideal gravel setup. Unfortunately I have an ‘old’ force derailleur, it will only shift a 10-33. Getting a new force/rival derailleur will give me access to a 36, but I was thinking it would be nice to get Eagle and have a 50T option for really big hills, but figured it would be overkill 99.9% of the time. That’s why I wanted to know if it would also shift the 36. Looks like eagle and rotor is a great option, 11-39 should be good for pretty much anything I’ll see in a gravel race, and with the option to go bigger.

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Yes, can totally relate. While I like my normal 2x red AXS with 46/33 front and 10-33 back for everything road, road bikepacking and local gravel and while I can totally live with 1x 32 front and 10-52 or 10-50 at the back for mtb use (and extreme gravel) I find it a bit aggravating that with all the 1x pushing Sram is doing they still have that gaping hole between their road/gravel setups and then everything they think Mullet is fine for.

In my eyes a 11-40 or even 12-42 or maybe 10-42 (if they insist on their 10 tooth cog) for 2x AXS is long overdue. Their decision to market a new “wide” cage Force (and now Rival) RD which just added the capability to shift upwards to the 36 tooth cog of their newish 10-36 and is already maxed out (it’s even printed on this RD “max tooth 36”) with this cog - thus already stamping it obsolete the moment they would finally cave in and make an aforementioned cassette boggles my mind. Or rather, seems like the usual marketing driven stunt Sram is known for.

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A long cage Force/Rival 11 speed can do up to 46. I use an 11-46 with Force RD on my cross bike, and a 9-46 with Rival RD on my gravel/rigid MTB.

Edit: realizing you mean 12-speed. I do wish they had made a long cage version of Force AXS but I guess that’s what Eagle AXS is for, with the benefit of getting away from the flat top chain.

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Thinking about it more I might go 10-36 and possibly switch to a 38T ring rather than going rotor 11-39. I have to buy a derailleur either way, and 38-36 is basically identical to 40-39.

I’m sure they’ve already made the 10-40 cassette and are just waiting to release it with a BRAND NEW derailleur just as soon as I buy the medium cage.

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That’s exactly what I’m thinking.

If it is of any help, I have been using an Ultegra 12-speed cassette with XTR 12-speed chain and Force AXS rear and front derailleurs and working perfectly so far. My front chainring is a Rotor AXS 48/35.

This could be really helpful for people that don’t want to switch to XDR hubs from their HG 11-speed.

Next to test on my end will be a set of non-AXS chainrings and will update my findings!

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Do you have more details on the exact setup you’re using? Including the frame it’s on.

Tried 12 Speed Ultegra Cassette and Force AXS RD - was a no go for me. Spacing was too different in between cogs.

I could be wrong, but I doubt that the frame makes any difference unless you have a bent derailleur hanger.

I have tried on two of my frames, both rim brake (Parlee Altum R and Madone 9.9), and in both it works equally good.
When I switch between wheelsets, one having a 10-28 Red Axs cassette and the other one an Ultegra 11-30 cassette, I just need to do some minor micro adjustments and that is it.

What chain are you using?

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Wondering if it’s a chainline or chainstay length issue that allows for it to work for you.

Strange as I have seen other people who have tried and not had it work either.

Full range of 12 speeds and no chain rub in any cog would be big news.