Box Two Prime 9 X-Wide Single Shift E-Bike Groupset - boxcomponents
Box Two Prime 9 X-Wide Single Shift E-Bike Groupset - Box®
Box Two Prime 9 X-Wide 12-50T Single Shift E-Bike Groupset
Box Two Prime 9 X-Wide Single Shift E-Bike Groupset - boxcomponents
Box Two Prime 9 X-Wide Single Shift E-Bike Groupset - boxcomponents
Box Two Prime 9 X-Wide Single Shift E-Bike Groupset - Box®
Box Two Prime 9 X-Wide Single Shift E-Bike Groupset - boxcomponents

Box Two Prime 9 X-Wide 12-50T Single Shift E-Bike Groupset

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Our Box Two tier's mission in life is to deliver performance similar to the Box One but without its exotic (and costly) features. With the Single Shift E-Bike Groupset you still get the Tri-Pack™ Clutch in our derailleur only it isn't adjustable. The cassette's 12-50T range is optimized for E-Bikes. The action on the shifter is limited to one downshift per lever swing. The chain boasts the same unique ability to mate with a wide/narrow chainring except you give up the trick DLC top coat. You're hardly shortchanging yourself with Box Two.

  • Our Most Durable Drivetrain
  • For Aggressive Terrain
  • E-Bike Optimized 12 Tooth Cassette
  • Single Shift Per Swing for E-Bike Safe Shifting
  • Install at Home with Some Simple Bike Tools and Our Easy to Follow Video
  • Tri-Pack™ Limited Slip Clutch 
  • Ultra-Wide Ratio with Consistent Progression
  • Compatible with Traditional Derailleur Hangers (Non Direct-Mount)
  • Cassette Compatible with HG Freehub Bodies
  • Prime 9 Technology™



Q: What is the difference between the Wide and X-Wide?
A: The Wide cassette offers an 11-46T range while the X-Wide offers an 11-50T range.


Customer Reviews
4.7 Based on 3 Reviews
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William W.
United States
Pretty good

The system works well. However, i would like if there was a little more push in the downshift. The lever has only a small amount of movement once it engages and doesn't allow for going slightly over the shift. So sometimes the shift won't go up on the initial change and you have to push a little more after the lever reset. Hope that makes sense. And yes, it's adjusted properly. Otherwise good.

Clive R.
Australia Australia
9 Ebike

Like it a lot. Very positive shift up and down and one run in it very positive in its changes

United States United States
excellent solution for ebike builds from old bikes with 9spd drivetrains

I found out about Box components from a bike trek web blog. I was setting out to turn an old 1999 Independent Fabrication Deluxe mountain bike into an ebike commuter since it was just hanging around in my garage gathering dust. I had a few obstacles to deal with and one of them was the drivetrain. The bike had a Sram 9.0 rear derailleur with a 9 speed cassette that didn't have the gear range suitable for my proposed mid-drive motor that I wanted to put on the bike. This is where Box came in. The X-wide drivetrain offered an excellent 50-11 gear range which coupled perfectly with the 46t chainring I was going to use on the drive motor. With that range, one could have easily gone with a 48t or 52t chainring and still been fine if you were to use the ebike strictly for rolling terrain commuting. (for curiosity's sake, I average about 25mph on my commutes which are about 20 miles each way). Functionality-wise, the Box shifting is insanely accurate. Once I got everything installed (*note on installation later), and tuned, the accuracy has been absolutely spot on. The clicks from the shifter are precise, never sloppy, and there's never any guess that you actually actuated the shifter. After several months and over 1200 miles on the drivetrain, the cassette has shown very little wear on the teeth. I'm using a 1000w Bafang motor on this bike which I've limited the top speed/wattage in order to stay road legal. Regardless, there is a TON of torque being thrown into this drivetrain. I have installed the shift sensor though so that the motor cuts out briefly between shifts. Even with all that torque, the drivetrain is holding strong. I can't say the same can be said for my V-brakes that just had a tension pin snap on me. A story for another review. Regarding installation. When putting the X-wide on a 26" wheel (my wheel is a ceramic coated Bontrager rim with an old Shimano XT hub), it looks a bit like you attached a dinner plate to the wheel. Furthermore, when you attempt to run the chain through and adjust the reach of the derailleur, it looks like it flat out won't work, but you just have to open up the limiter adjustment screws and do an initial eyeball on the angle screw and run the chain. The derailleur will reach and it won't be at all messy. If you attempt to push the derailleur by hand, it'll look like it's not going to work. Once you have the chain in place and initial tension on the cable, you can then make adjustments to the range by setting the angle screw appropriate for whatever frame/wheel setup you have, and then refine the range by adjusting the high and low limiter screws. Bottom Line, it WILL work if you take your time and see the ingenuity behind the Box rear derailleur design.