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Upgrading to 12 – A How-To Guide

Duration: approx. 45mins

How do you upgrade to 12 speeds and set up a wide-range 1x drivetrain? What tools will you need? Is it difficult?

With Ratio Upgrade Kits, you can run a SRAM Eagle™ drivetrain with drop-bar shifters on your road, gravel or ‘cross bike. The kit’s compatible with a large range of SRAM components and the only parts you’ll need to modify are a set of 11 speed mechanical shifters and an Eagle™ derailleur. All the modifications are completely reversible. It will take about 45 minutes.

All SRAM 11 speed shifters road shifters are compatible, but Eagle™ derailleurs from the SX™ and NX™ groups are not as it is not possible to replace the cable fins on these derailleurs. We would choose the GX™ derailleur regardless as the cost increase is small and it’s fitted with much more reliable hardware, including sealed bearing jockey wheels. For more information on compatibility, see our compatibility guide.

There are cassette options for most free hub standards (except Campagnolo, sorry). Eagle™ cassettes are available for XD™/XDR™ (with 1.85 mm spacer) or Shimano HG freehubs. Eagle™ cassettes for HG freehubs have an 11 tooth smallest sprocket instead of a 10 tooth, reducing the total range from 500% to 455%.

The upgrade requires some experience to perform, but if you’re someone who already works on your own bicycle then you won’t have any trouble. If you’re not confident, contact your local bike shop and direct them to this guide.

The upgrade involves two steps: fitting the 12 speed ratchet to the shifter, and fitting the Ratio cable fin to the derailleur. The process is slightly different depending on whether your 11 speed shifters are designed to be used with hydraulic brakes or cable brakes. The upgrade can be completed using the following list of tools:

Upgrading the shifters

Follow our video guides to fit the 12 speed ratchet to your shifters. Take care to follow the appropriate video for your shifter type:

Video guide: Shifters for hydraulic brakes
Video guide: Shifters for cable brakes

Upgrading the derailleur

In order to run your Eagle™ derailleur with road shifters, you need to fit the Ratio cable fin. Please follow our video guide:

Video guide: Cable fin replacement

There’s a small circlip that holds the cable fin onto the derailleur. Don’t panic – if you lose it, you’ll find a spare in your kit.

Finally, your frame designer probably expected you to be able to change your derailleur cable tension with an adjuster on the derailleur. Mountain bike derailleurs like Eagle™ don’t have these as standard, but we’ve included one in the kit. Simply slot it into the cable stop in the derailleur and you can fine-tune your gear indexing.

That’s it! You’re now ready to fit the shifters and derailleur to your bike as you would any other groupset. If you have any trouble setting up your drivetrain, please refer to the instruction booklet included in your kit or on our support page. If you have any further questions please contact us.

Finally, please note that modifying your SRAM components may void their original SRAM warranty. Ratio Technology Limited is in no way linked to SRAM LLC.

19 thoughts on “Upgrading to 12 – A How-To Guide”

  1. Hello, this looks brilliant. Great work!
    I have a 1x SRAM Force set up with a wide ratio (11-36t I think).
    It’s a single speed road bike and I was hoping to get another gear.
    Do you think this would work?
    Was hoping to get something with a tighter ratio but struggling to find 12sp cassettes without going the xdr route. Thanks

    1. Hi David. You can definitely upgrade to a wider-range Eagle setup using our kit with an Eagle chain, cassette and derailleur. Alternatively, if you are willing to consider an XDR freehub, we’ll shortly be launching a version of the kit to use with SRAM’s road 12 speed cassettes. If you want closer-ratio 12 speed using the current kit, you’ll need a cassette with the same sprocket positions as Eagle. A few people have had a good experience with Sensah 12 speed cassettes, which are available in the range you’re after.

      1. that’s great! I’m really looking forward for this solution 1×12 on race bike with 10-36 force/rival cassette and my force CX1 derailleur.

  2. Hello! Is it possible to run just the fin on a GX Eagle with an 11-50 11 speed cassete, using Apex 11 speed shifters ?

    1. Hi, it is. The GX Eagle derailleur is X Actuation as stock. Fitting the fin converts it to Exact Actuation, which means you can operate it using Exact Actuation 11 speed road shifters.

  3. Hi I was just wondering, technically if you replace the ratchet in the shifter for the 12 but then wanted to go back to running 11 speed, would you have to revert the ratchet or could you just leave it in, and run it on an 11s derailleur?

    1. Hi, you’d have to swap the ratchet back to 11 speed as the shift positions of the two setups are different. However it’s a fairly simple job once you’ve done it the first time – we regularly make swaps with the cables and hoses still routed on the bike.

  4. Hi Tom, really loving your team’s products! Any thoughts on creating upgrade kits for 13-speed Rotor or Campagnolo cassettes in the future? Thanks!

    1. Hi. It’s certainly something we can think about, using SRAM 11 speed shifters again. I expect the number of options for the Campagnolo N3W freehubs will grow rapidly over the next few months which will also increase the appeal of the Campagnolo cassettes. Keep an eye on our website and social media!

  5. What problem arises when you try to use the kit with
    road derailleurs or cassettes?

    Any timeline for the coming kit that will allow running a narrow range 1×12?

    1. Hi. The positions of the sprockets in the AXS road cassettes is not quite the same as the wide-range Eagle cassettes. Because our wide-range kit is designed specifically for the Eagle sprocket positions, using it with AXS road cassettes could result in slow and noisy shifting in some gears. We’re developing a close-ratio 1×12 and 2×12 version of the kit at the moment with the aim of making it available by the end of January. Hopefully we can release it earlier than that – once we’re further down the development route we’ll try to fix a release date and consider taking pre-orders on the new kits.

    1. Hi Kirill. We have had a few people ask about this and we have checked it out. Unfortunately Sram changed the geometry of the plastic cable spool in the shifter between the generations. This is the part that holds the derailleur cable and the shifter ratchet has to fit into it. Because the fit was changed, our current ratchets are specific to the 11 speed levers. The one caveat is that the ‘new shape’ Red 10 speed levers may have the 11 speed cable spool and therefore be compatible. We’ve heard from one customer who claims this is the case, but unfortunately as yet we haven’t tracked one of these shifters down to check for sure.

      1. I have the ‘new shape’ 10-speed Red shifters it could be tried out on if you like (I’m based near Cambridge). I’m really after going from 10- to 11-speed on the road (rather than to 12-speed for gravel), but I’m guessing you could tell anyway if the spool looks right?

        1. Hi, thanks for getting in touch. If you drop us a message on the contact page we’ll see what we can do. We might be able to help with your upgrade.

    1. Hi Francesco. Drivetrain manufacturers don’t generally recommend mixing components from different gear number groupsets, which is why we also recommend that you use a 12 speed compatible chainring. However, in reality the difference in internal width of the 11 speed and Eagle 12 speed chains is only around 0.1 mm. This means that many people (including us) have tested Eagle 12 speed chains on 11 speed chainrings with no problems. The risk is that the width difference leaves less space for debris to leave the chain, so if you run the setup in very muddy conditions you may find that the chain rides off the 11 speed chainring when it would perform better on a 12 speed chainring. You should be aware of this if you choose to keep your 11 speed chainring. I hope that helps!

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