To upgrade to 12 speed, you first need to work out which components you’ll need. Follow this guide to ensure you buy the right Ratio kit for your setup.
Ratio Upgrade Kits – Forward and rear cable exit
The Ratio 1×12 Wide Upgrade Kits are divided into two versions: Forward Cable Exit and Rear Cable Exit. To find out which Ratio kit you need, simply follow this rule:
If your chain stay/seat stay cable stop is over 70 mm from the dropout, use the 1×12 Upgrade Kit with Forward Cable Exit. If it is under 70 mm from the dropout, use the 1×12 Upgrade Kit with Rear Cable Exit.
The derailleur cable generally exits mountain bike derailleurs (such as the Eagle™ derailleur) from the front. This leaves a smaller loop of cable to snag on undergrowth, but is incompatible with a number of road-orientated frames. In contrast, the derailleur cable on road derailleurs leaves from the rear – producing a large loop of cable that returns to the frame.
The derailleur cable is secured to the frame with a ‘cable stop’ on the chain stay or seat stay. If it’s internally routed, there’s a similar point on the chain stay or seat stay where the cable enters the frame.
If this point is too close to the dropout (and therefore the derailleur) the cable may have to bend tightly to reach the derailleur, resulting in cable drag. In some cases it may be impossible to route the cable into the derailleur.
The Ratio 1×12 Wide Upgrade Kits are compatible with all mechanical 11 speed SRAM shifters, whether for cable or hydraulic brakes*. This includes shifters from the Red™, Force™, Rival™, Apex™ and S Series™ groups. As the 1×12 Wide kits are for 1x drivetrains, you can use 1x or 2x shifters. If you use 2x shifters, you can remove the left hand shift lever or use it to actuate a dropper post.
Most SRAM 10 speed shifters are incompatible with the Ratio kits as the cable spool in the shifter is a different design. This means that the Ratio ratchet cannot be fitted to these shifters.
However, there are a small number of 10 speed models that use the newer 11 speed cable spool. This plastic cable spool can be identified by its red colour. To our knowledge, these models include ‘new shape’ 10 Speed Red™ SB-RED-B1 and some versions of the ‘old shape’ 10 Speed Red™ shifters. If in doubt, please visually check that you can identify the cable spool as the red (colour) 11 speed version.
The 1×12 Wide Upgrade Kits are designed for SRAM Eagle™ derailleurs. The Forward Cable Exit version of the kit should be used with derailleurs from the GX™, X01™ or XX1™ groups*. SX™ and NX™ derailleurs are incompatible because the cable fins on these derailleurs cannot be replaced; this means they cannot be used with road shifters.
The Rear Cable Exit version of the kit should only be used with X01™ or XX1™ derailleurs*. The Ratio Rear Cable Stop cannot be fitted to GX™ derailleurs using normal bicycle tools. However, we offer pre-modified GX™ derailleurs in a bundle: 1×12 Wide Upgrade Kit + Rear Exit SRAM GX Derailleur.
Our 1×12 ratchets have been designed to provide optimum shift positions on SRAM Eagle™ cassettes. Some customers have had good results using alternative cassettes with similar sprocket positions; we will update our guidance on cassettes as we complete more testing.
You can add a SRAM Eagle™ cassette to your kit order here.
As a general rule, drivetrains will shift best when the chain and cassette are supplied by the same manufacturer. This is because shift ramps on the cassette are engineered to engage with specific chamfers on a given manufacturer’s chain. When upgrading to 1×12 you should ensure you use a 12 speed chain. Note that Shimano 12 speed chains are not compatible with other manufacturer’s cassettes and chainrings.
You can add a SRAM Eagle™ chain to your kit order here.
1×12 drivetrains should be used with 12 speed compatible 1x chainrings. Using a non-1x chainring could result in the incorrect chainline for your drivetrain and your chain falling off the ring.
Although we don’t recommend using 11 speed chainrings, the teeth on these rings are around 0.1 mm wider than the teeth on a 12 speed chainring. Once an 11 speed chainring is worn, the teeth may be narrower. A 12 speed chain on a new 11 speed chainring will not clear mud as effectively and could fall off.
*Please note that modifying these components may void the original SRAM warranty. Ratio Technology Limited is in no way linked to SRAM LLC