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  • How to convert your mountain bike to a 1BY drivetrain

    May 5, 2015

    How to convert your mountain bike to a 1BY drivetrain

    Between SRAM’s groupsets, direct mount cranks, and extended range cogs, there are plenty of options to convert your bike to a 1BY mountain machine

    In 2013, SRAM shook up the MTB component scene when XX1 hit the market. Rather than the latest-and-greatest drivetrain getting more complicated, they ditched the front derailleur all-together in favor of the simplicity of a single-ring setup. It was a revolutionary move and one that has since influenced all corners of mountain biking; from cross-country race, to all-mountain and enduro, and downhill – even spilling over into cyclocross.

    First, what’s 1BY?

    1BY (1X), or 1×10 and 1×11, refers to a single-ring drivetrain where only one chain ring is connected to your crank, and a 10- or 11-speed cassette in the rear of your bike. This differs from the traditional setup where you have 2- or 3-chainrings up front and a derailleur to change gears.

    So what’s all the hype about?

    1BY setups have been around for a while in the cross-country race scene, but few mortals were able to take advantage of the single front ring setup with a conventional 11-32 or 11-34 tooth cassette (and still pedal comfortably). When SRAM released XX1, the 1BY movement became a viable option for “average” riders.

    But the 1BY story is about more than just a single ring front crank – it’s a system. By expanding the gear ratios in the rear cassette (10-42T), your everyday rider can now run a single ring up front and get the same gearing as a standard 10×2 or 9×3 setup.

    Why make the move to 1BY?

    There are three main benefits: single-ring drivetrains are lighter weight, offer better ground clearance, and are more reliable than a traditional 2- or 3-ring setup.

    A 1BY drivetrain means there’s no front derailleur to fiddle with, and that means fewer headaches on the trail and less maintenance overall. Shifting is simplified, and that’s something that riders of all abilities will appreciate; from novices just getting the hand of their gearing, to racers looking for reliable shifting when every second counts.

    An added plus, no front shifter also means more real-estate on your bars for that dropper post lever, or suspension lockout. If you run a narrow wide front ring, in most cases you can also chuck your chain guide and forget about dropped chains.

    Below are three options to convert your Norco mountain bike to 1BY, starting with the smallest investment and moving onward and upward from there.

    Option 1: Convert your existing cranks to 1BY (narrow-wide) and modify your 10 speed cassette.

    Kick your granny gear to the curb and swap out your middle ring for a 28T or 30T narrow wide chainring (like ones made by SRAM, e13, or Blackspire) for fewer dropped chains. For comfortable climbing, install an extended range cog to expand your cassette to 40T or 42T. Remove your front derailleur, cables and front shifter, and rejoice!

    Option 2: Replace your front crank to a dedicated 1BY crank and modify your 10 speed cassette.

    There are a few new 1BY cranks hitting the market designed for optimal performance with large range rear cassettes. E13’s TRSr cranks feature a dedicated 1BY chainring with narrow wide tooth profiles, plus shed weight by going to a direct spiderless chainring interface.

    Pair this crank with E13’s rear EX cog and your set to hit the mountain in style and performance.

    Option 3: Replace your complete drivetrain over to SRAM XX1, X01, or X1.

    If you want the best-of-the-best for your bike, then converting your complete drivetrain over to 1BY is the way to go. Forget 1×10 setups, and crank it to 11 for the full experience.

    Why 11-speed? Besides additional weight savings, the real answer is in the expanded gear range. Due to the interface of traditional 10 speed freewheels, you can only go down to an 11T cog. By converting your bike over to 11 speed (with a XD freehub body) your rear cassette can now start at a 10T, giving you the largest rear cassette on the market today (10-42T). By having a larger cluster in the back, you get more options when paired with a single front chainring.

    But converting to 1×11 does have its costs. In order to convert, you need to purchase a new crank, cassette, chain, derailleur, and shifter along with a new XD freehub body or rear wheel (if your current rear hub is not convertible to XD). On the bright side, you don’t need a front derailleur or front shifter.

    SRAM currently offers three complete drivetrains for 1×11: XX1, X01, and X1. XX1 caters to the elite rider with optimal weight saving and stiffness, while the X01 and X1 options provide the same ride characteristics in more affordable packages.