Can’t wait until more drivetrain manufacturers join Rotor in producing a 1 x 13 set up? Well, if you have the desire to create your own SRAM mechanical 1 x 13 set up, Black Water Cyclist’s latest video will show you how…
Hack your SRAM mechanical drivetrain into a 1×13!
While this would certainly be considered a hack, it’s more involved than just tinkering with your current set up.
The key to the whole thing coming together is a SRAM mechanical shifter that has been modified by Dirk Stock. Apparently, you can purchase the modified shifter from Dirk which have a new index wheel with 14 indentations with spacing that matches the 12 speed SRAM AXS cassettes. Technically, that would make it possible to make this a 1 x 14 drivetrain, but here it’s limited to 13 shifts due to limitations at the cassette. The partial shifter can be purchased for €199 (about $235), and you’ll still have to install your own brake lever and master cylinder, so this is not for a complete shifter. You’ll definitely need to be a skilled mechanic to put it all together.
To create a 13 speed cassette with the right spacing, it’s apparently possible to simply mount the cassette on top of the adapter on an XDR freehub if you’r using the Fouriers adapter shown above. This adapter reportedly has a thinner width which results in enough spline to mount both to the XDR freehub. Other adapters can be used, but require additional machining to fit. 
The extra width may interfere with some frames, so Dirk provided a pedal washer with an ID that’s enlarged to slip over the thru axle and act as a spacer. Obviously, this widens the overall width of the hub and will probably void any warranty. This should go without saying, but the moment you start ‘hacking’ your bike, don’t expect any manufacturer’s warranty to cover anything if it goes wrong. But if you’re even considering a drivetrain hack of this level, you’re probably already aware of that. As with any hack, you do this at your own risk.
Finally, to make it all come together, a SRAM Force 1 derailleur is used to provide the clearance for the bigger cassette. Only, the narrow-wide pulleys won’t mesh with the 12 speed SRAM Flattop chain. So the wider teeth were ground down with a Dremel.
In the end, everything seems to work surprisingly well though it will be interesting to see what the increased chainline at the cassette will do to the system’s longevity, and how well it will continue to shift over time. To find out, Black Water Cyclist says that he’s planning on some follow up videos to address just that, so make sure to subscribe for updates.
Thanks to Billy for the tip!
