"Road" cassette for mountain bike running eagle 12 speed

Hello,

So I’m using my mountain bike for a gravel ride in a couple of months. It’s got the sram eagle 12 speed 10-50 cassette and a 32 tooth chainring. I don’t figure I’m going to need much more than a 1:1-ish ratio and would like to find something like a 10-36 or maybe 10-40 or 42 instead of carrying the big pie plate around.

I tried to look for options but…somehow the eagle stuff has me confused. Is what I’m looking for “a thing”? Is it possible? Thanks :slight_smile:

Joe

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Get a bigger chainring for the gravel ride if you can instead. That is a cheaper and better option than a smaller cassette.

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One option is switch to a 34 or 36 front chainring.

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100% with you but the frame will only accept a 32, unfortunately!

SRAM Road 12 speed cassettes use the XDR driver, and the SRAM Eagle stuff uses the XD driver. The XDR is 1.85mm longer than XD so you can’t use an XDR cassette on an XD driver; you can go the other way (XD cassette on XDR driver) with use of a spacer.

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OK, XDR is wider, XD mountain bike cassettes can go on XDR wheels with a spacer but not vice versa. Thanks :slight_smile:

Are you saying 10X50 is my option here?

Not sure about your price range but e*thirteen makes a 9-46 tooth 12 speed cassette that fits on an XD driver. I’ve never used it so I don’t know how well it works though.

The Eagle Chain doesn’t work with the road cassette. The flat top chain probably won’t work with your Eagle ring. I’d do a SRAM 11-42 Cassette on a Shimano driver. It’d be cheaper than a 10-36 anyway.

The flat top road chain does not work with the eagle RD. I’m pretty sure the eagle MTB chain does work with the road stuff though. I’m pretty sure I’ve run it, but not positive.

My gravel bike has force AXS with the power meter dub crank. If I have a particularly “pitchy” gravel event, I can pull my Eagle AXS RD and 10-50 cassette off my MTB and pair it with my force AXS shifters. My wheel has the XDR driver. I also swap out the front chain ring for 40. It’s a 10 minute thing, really slick design on that crank. That’s enough gearing to keep up in almost any gravel race, but I don’t care for the big jumps between gears. I prefer the 2x road setup for almost all my gravel racing.

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I don’t think sram makes a 12 speed cassette that fits a shimano driver…do they?

So for pitchy events you run a 40 x 10-50 setup? That sounds pretty good but I’m limited to 32 on the front ring.

Rotor 11-36. I don’t know of much/any on the XDR driver side that can get you a 9 or 10T. Maybe when Shimano’s 12 speed road comes out, there would be microspline options.

I think Rotor’s 12-speed cassette might work, though.

Yeah, regardless of whether you have a road or mtb cassette (with a 10 tooth cog), you are going to be limited by your chainring for top end speed.

What frame do you have and have you tried a larger ring? I’ve done a bunch of gravel racing on my Scott Spark RC and it’s “officially” limited to a 34 front ring, but I run a 36 no problem. Nino runs a 38 on the same frame. Running a 36 in the front and 10-50 in the back, I have never been dropped in a gravel race due to gearing limitations. 34 would probably be fine also. All dependent on course and conditions.

I don’t think you’d notice the extra few hundred grams of an Eagle 10-50 on what’s presumably a 25-30lb mountain bike…

Yes, they offer the 2 cassettes (12-spd, 11-50) for the old Shim/SRAM driver:

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Well that is true. I was going for smaller jumps between the little cogs and a straighter chain line to the 12/13/14 t cogs but I think ultimately you’re right…just run 32x10-50. Wide range, simple, paid for lol. Ima do that.

Thanks for the ideas guys :slight_smile:

So you can mount the Eagle cassette on an XDR driver?
Haven’t looked that deep into it yet.

Replying to myself here:

uh, nice:
Sram says: “XDR driver bodies are compatible with all XD cassettes when the cassette is installed with a 1.85mm spacer behind it.”

and on Weightweenies someone mentioned “I installed a 10-50 xx1 eagle cassette onto a DT Swiss xdr driver without a spacer and it works fine (even though SRAM says you need a spacer). The cassette tightened down just fine and I have good clearance between the 10t cog and the frame.”

Well that last one may or may not work on an individual frame/wheel combo.

Ability to tighten on the body is one thing. Leaving the spacer out will position the cassette more inboard, changing the effective chain line. It may also lead to the derailleur being too close to the spokes when in the lowest gear.

I see no reason to ignore the manufacturer info to use the spacer as directed.

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