Ratio Technologies' new upgrade enables you to convert your bike to a 1x SRAM XPLR drivetrain without replacing your rear derailleur.Instead, you only need to replace the chain and cassette to turn your 33 or 36t max-capacity 12-speed mechanical SRAM AXS road rear derailleur into a 1x-specific XPLR version.The upgrade kit enabled you to run up to a 45t cassette marginally more generous than SRAMs 44t capacity.The Ratio SR45X cage extends the derailleurs B-knuckle while the cage introduces an offset upper pulley wheel.The upgrade kit could also be a good option if youve damaged an XPLR derailleur SRAM doesnt currently offer a replacement cage for these derailleurs.The SR45X Link will retail for 104.50 including a link or 94.50 for the cage only (international shipping available).Whats included in the kit?These are the parts you get in the kit. - Ratio TechnologiesThe new cage uses a 12t upper and a larger 14th lower pulley identical in size to those found on Ratios cages for SRAM Eagle rear derailleurs.The cage includes 7075 aluminium plates and acetal thermoplastic pulleys. These are manufactured in-house by Ratio and assembled with stainless bearings and hardware. You also get a custom stainless steel tool in the kit, which is required to undo the nut that holds the cage onto the derailleur.The kit is available in black or silver and is claimed to weigh 66g, or 75g with the link.You cannot use an Eagle cassetteSRAM's road / gravel cassettes are not inter-compatible with the brand's Eagle mountain bike cassettes. - Jack Luke / Immediate MediaRatio Techonlogies says you must use a 12-speed XPLR or an AXS-compatible cassette, such as e*thirteens Helix 9-45t. This is because the cog spacing differs between SRAM road/gravel cassettes, and its wider-ranging Eagle mountain bike cassettes.Ratio says when you add its SR45X cage and link to a maximum capacity 33t rear derailleur, it not only increases the B-knuckle length to match the XPLR model, but also adds an offset jockey to increase the total capacity to 45t.The brand says it did this to help the derailleurs performance if youre using an aftermarket cassette, such as the aforementioned e*thirteen option.If youre converting a derailleur with a 36t maximum capacity, Ratio recommends shortening the chain length by two links to swing the derailleur forward and reducing the B-gap.