12 Speed Instruction Booklet


Rear exit cable stop fitting


How-to video guides


Can I run another manufacturer’s cassette?

There are a number of aftermarket cassette manufacturers supplying 12 speed cassettes designed to work with Eagle drivetrains, in addition to other brands’ 12 speed cassettes. We’ve had a number of enquiries into compatibility with cassettes from Shimano, Rotor, E*Thirteen, Garbaruk and others. Unfortunately we haven’t yet been able to test these alternative cassettes and confirm that the shifting performance meets our standards, so currently we advise that you use the kit with an Eagle cassette. However we may update this advice as testing continues.

Is the upgrade kit compatible with road cassettes and derailleurs?

A lot of people are keen on a lower-priced way to run Sram’s smaller range 12 speed road cassettes. Unfortunately the current 12 speed Eagle upgrade kit isn’t compatible with road derailleurs or cassettes. However, we’re currently working on another kit that will allow you to run narrow range 1×12 or 2×12 – keep an eye out here and on our social media.

My cable routing isn’t compatible with the upgrade kit – what can I do?

We have kits for all cable routes to the rear derailleur. See our compatibility guide to find which one you need

Which chainrings can I use with my 12 speed drivetrain?

Check manufacturer’s specifications for compatibility with Eagle® 12 speed chains. You need a 1x chainring as the chainline needs to be designed for a single ring drivetrain. We recommend using a chainring designed for compatibility with 12 speed chains.

What components do I need to set up a 12 speed drivetrain on my drop bar bike?

You’re building up a bike and you want to fit a wide-range mechanical 12 speed drivetrain. You’ll need:

  1. A Ratio 12 speed upgrade kit.
  2. A set of Sram® 11 speed levers. They can be for cable or hydraulic brakes, but the right hand shifter needs to be mechanical. The left hand lever can be 1x-specific (no shift lever) or you can use a 2x shifter and take the shift lever out or run a dropper with it.
  3. A Sram® Eagle® derailleur from the GX®, X01® or XX1® groups. You can’t use an NX® or SX® derailleur because the cable fin is riveted in place.
  4. A Sram® Eagle® 12 speed cassette. We can’t confirm that aftermarket cassettes will perform properly with your drivetrain.
  5. A 12 speed chain for Sram® Eagle® drivetrains.
  6. A 1×12 speed compatible chainring.

I want to upgrade my derailleur/shifter – can I swap the kit over?

Yes – the process is fully reversible. Refer back to the installation videos on the product page but swap the upgrade parts for the ones you took off.

How do I index my gears?

You should index your gears when you set up your drivetrain, and check the indexing periodically as your derailleur cable beds in. To index your gears, follow these steps:

  1. Shift into the smallest sprocket. If you can’t shift into the smallest sprocket, turn the barrel adjuster clockwise (facing the derailleur) until you can, loosen the cable clamp bolt until you can or release the lower limit screw of the derailleur until you can.
  2. Clamp the cable so that it’s slightly loose in when the derailleur is in the smallest sprocket. The limit screw should be adjusted so that the upper jockey wheel of the derailleur is in line with the centre of the smallest sprocket, and the chain is quiet when you rotate the pedals.
  3. Shift into the second largest sprocket, then wind the barrel adjuster anticlockwise until the chain shifts.
  4. Shift across the cassette, up and down. If the shifts to bigger sprockets are slow, turn the barrel adjuster anticlockwise in quarter turn increments. If the shifts to smaller sprockets are slow, turn the barrel adjuster clockwise.
  5. The upper limit screw should be set so that the chain can’t fall off the largest sprocket. However, it should be just loose enough that, if you try to shift up from the largest sprocket, the shifter drops back into the same gear.
  6. The B screw should be adjusted according the derailleur manufacturer’s instructions. The gap between the upper jockey wheel and the largest sprocket should be 14 mm.

Why isn’t my drivetrain shifting properly?

If you’re experiencing shifting trouble (slow upshifting, slow downshifting, non-uniform shifting across the cassette or noisy operation) there are a few different things to look for. First, you should make sure that you’ve fitted the kit according to the included instructions and that your gears are indexed properly – have a look at our indexing FAQ if you’re unsure about this.

  1. Check the condition of your derailleur cable. If it’s damaged or old, your shifting will feel stiff and the cable won’t release properly. This means your derailleur will be in a different position when you shift down to a gear than when you shift up to it. If you’re in any doubt, replace the cable – they’re not expensive and it will always help!
  2. Check that your derailleur hanger is straight. Even a small bend can throw the shifting off – use a proper tool such as the Park DAG-2. A bent hanger won’t necessarily be obvious from looking at the derailleur; contrary to popular understanding, Sram® 1x derailleurs do not remain parallel to the hanger through their travel.
  3. Check for cable drag elsewhere in the system: release the cable from the derailleur, hold it in your hand and shift up and down to feel for drag in the cable release. We’ve seen shifters where grooves have worn in the housing and bind the cable, or internal routing where the derailleur cable is tangled around a hydraulic hose.
  4. Look for damage to the derailleur itself. If you’ve crashed or dropped the bike, it’s possible that you’ve bent the derailleur. This could be in the form of a bent jockey cage, or damage to the parallelogram sections or pivots that throws the derailleur geometry off.