Remember how we shared with you the SRAM Eagle hack that converted your current SRAM 1×11 groupset to work with a wide-range cassette? Now Ratio Technology in the UK has taken it a step further, with a new and more advanced DIY Upgrade Kit that takes your 11-speed mechanical setup all the way to 12 speed. Bring on the mechanical mullet!

Ratio DIY Mullet 12 speed Upgrade Kit: 11sp mechanical to Eagle

Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, DIY

c. Ratio Tech

Ratio’s conversion kit will take a bit more do-it-yourself mechanical aptitude than Parallel Handbuilt’s BudgetMullet Eagle 1×11 hack, but the idea is the same. Tons of cross and gravel cyclists already have a perfectly functional SRAM 1x 11 speed mechanical drivetrain, and would love to get the gearing boost of Eagle mountain bike cassettes. And SRAM fully supports the ‘mullet’ setup of dropbar shifters mated to an Eagle rear derailleur… but the only solution they provide is the quite expensive wireless AXS eTap setup. But…

c. Joergen Trepp of Parallel Handbuilt

Parallel Handbuilt taught us how simple it was to hack together the dropbar shifter cable fin from your current 1×11 road/CX/gravel rear derailleur and stick it onto a new SRAM Eagle mountain bike rear derailleur. But that only got us the compatibility with wide cassette range. To go to 12 speed, you would need another tooth on the internals of your shifter.


Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, ratchet

Ratio Tech 12 speed ratchet

Ratio created their own 3D-printed stainless steel Ratio 12-speed ratchet, , so you get shift spacing designed just for an Eagle mountain bike derailleur with your existing drop bar shift lever. The catch, you have to take your shifter apart and rebuild the internals yourself.

Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, kit

Ratio 12 Speed Upgrade Kit

Ratio just sells you the DIY kit. But that £50 kit includes the new 12-speed replacement ratchet gear, plus a cable fin that they 3D printed from reinforced nylon (so you don’t have to take apart a 11sp road derailleur), a cable adjuster that you can add to the new Eagle derailleur to fine tune tension, a spare fin circlip, and the M2.5 bolt that hold the new ratchet in place.

How To: Ratio Technology dropbar Mullet Eagle 1×12 hack


And they have a detailed series of videos to guide you step-by-step through the entire upgrade process. There are three instructional videos: one to upgrade a SRAM mechanical brake/shift lever, one to upgrade a SRAM hydraulic brake/shift lever, and one to upgrade the cable fin and barrel adjuster.

Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, new drivetrain

c. Ratio Tech

It’s not a super simple DIY job, but Ratio thinks most capable home bike mechanics shouldn’t have too much difficulty.

Besides the normal tools you will need to undertake the job, the £50 kit does not include a new SRAM Eagle rear derailleur (obviously) so you’ll have to buy one of those – XX1, X01, or GX mechanical Eagle derailleurs will work (SX & NX will not).

Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, SRAM lever

c. Ratio Tech

You also of course need a set of 1×11 shifters to put the new ratchet in. Ratio says their kit will work with Red, Force, Rival, Apex, or S-series levers – both rim brake or disc brake.

Then once you finish, you will need an Eagle 12 speed cassette, and of course a compatible rear wheel with an Xd/XDR driver body (or of course an NX or SX cassette that will work on a Shimano freehub, but with a limited 11-50T gear range.) Your 1x front chainring will also need to be 12sp-compatible, as will your new chain.

Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, lever upgrade

c. Ratio Tech

It’s not as simple as say installing a new cassette or bolting on a new derailleur, but it doesn’t seem that complicated either. (One caveat is that you need to be sure that your cable routing will work, but Ratio has some helpful diagrams to make sure your frame is compatible.) And for sure this could be the cheapest and cleanest DIY solution we’ve seen yet to upgrade to a mullet 12 speed setup on your gravel or adventure bike. In fact, writing about it makes me want to buy a kit for my old cyclocross bike.

Ratio DIY Mullet 12 speed mechanical Eagle Upgrade Kit, 11sp SRAM mechanical to 12 speed Eagle conversion hack, complete

c. Ratio Tech

The kits apparently just came into stock today, even though they are still listed as “Available on back-order” on Ratio’s site. But in any case, you can place a back order for the kit now, with them expected to ship by the end of this week if you act fast.


  1. luddite on

    Never mind all that nonsense, what is that lovely blue bike with Rob English style skinny stays?? There is another pic on the website and it has a kind of triangular head badge, something-M-P-something?

  2. Chris on

    Will they release a kit that has the correct “fin” so that you can do this for a road rear derailleur too? I’d love to have mechanical 12 speed SRAM RED with rim brakes.

    • Mayhem on

      No, because there is not fin to replace, and it wouldn’t be needed.

      The job of the replacement fin is to convert and X-Actuation Derailleur to instead work with Exact Actuation cable pull ratio, the same as already used on all SRAM road derailleurs.

      If you could find a smaller 12-speed cassette that still has the same spacing as Eagle, that should work with a shifter modified with this kit together with a standard SRAM road derailleur.

      From what I am told existing Red/Force 12-speed cassettes are narrower and will not work with this kit. Ratio Technologies are however working on a separate ratchet replacement to match those!

  3. Jason on

    Why are you writing: “…Then once you finish, you will need an Eagle 12 speed cassette, …’?!

    A 12x cassette from Shimano (for example the 10-45) should work the same way, or?

  4. John on

    I’ve never really been a fan of SRAM’s double-tap shifting system, but this conversion kit is freaking brilliant!!!

    It’s obvious from their MTB shifters that a mullet dropbar brifter was doable, I assume their beancounters were afraid of cannibalizing wireless AXS sales.

    One question: Are the engineers at Ratio sure that SRAM’s NX 12-speed 11-50t splined cassette (PG-1230) wouldn’t work with this system? The spacing is identical to their 12-speed SX & GX cassettes, and that would open this kit up to a lot of bikes with Shimano-style splined freehub wheels.

    • Mayhem on

      Where has anyone claimed that NX cassettes won’t work? Official website says any Eagle cassette, as expected.

      It is only the derailleur where NX and lower will not work, because the cable guide fin is riveted in place on those. To remove it you’d have to drill it out and in the process destroy one of the pins holding the derailleur together.

      • satanas on

        That should mean any SRAM compatible MTB 12 speed cassette should work, and there are others that fit on HG hubs, including Sunrace, Garbaruk, etc. These fit on 8/9/10 speed hubs too, no 11 speed road hub required.

        • Cory Benson on

          @John, @May & @Satan… Yes, either an NX or SX Eagle 11-50T cassette will also work, and use the Shimano-style HG freehub that the original 1x 11speed SRAM groups already use. It was my own note suggesting the XD upgrade for the full Eagle (now extended) range.

          • John on

            Thanks @Cory, @satanas and @Mayhem, I must’ve read too much into the requirement for XD/XDR. Going to order one of these to convert my GF’s 2×11 gravelbike to 1x.

  5. John on

    One other thing, for anyone that hasn’t taken a Shimano brifter apart, I wouldn’t expect a Shimano version of this kit any time soon. LOL!

    • Jason on

      aren’t the sprocket spacing at Shimano cassettes different from Sram?
      (I heard that Sram Eagle dereilleurs won’t work perfectly in combination with Shimano 12speed cassettes, or am I wrong?)

      • satanas on

        SRAM would certainly like everyone to think their cassettes were mandatory. I’ve not seen actual measurements anywhere, but it seems people are getting away with swapping Shimano and SRAM shifters and/or derailleurs into the other system; I haven’t tried it so it might all be speculation considering what “works okay” means to some.

  6. Josh Winer on

    Hey there! Do I need to do anything different (spacer?) if I’m running XDR freehubs vs XD? Using an Eagle 10-50 cassette, with a GX RD and the Ratio 12 speed kit…


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