SRAM EX1 e-bike drivetrain review

Awesome shifting under power

Components E-bike
The EX1 group is finished off with robust chain, shifters and brakes.

The EX1 group has a robust chain, shifters and brakes.

EX1 X-Horizon Rear Derailleur

The X-Horizon derailleur is more robust to handle heavier loads. It features 12-tooth X-sync pulley wheels and is designed to handle 8 speeds of up to 11-48 gearing.

  • Speeds: 8
  • Cable pull ratio: 1:1
  • Max tooth: 48
  • Color: black
  • Pulley bearings material: Steel
  • Cage material: Aluminum
  • Weight: 289g
EX1 X-Actuation Trigger Shifter

The EX1 trigger shifter is a delight to use, as shifts are light action yet very positive. That double shift is gone and the rider will find themselves pushing hard on the downshift button to find that extra shift.

  • Speeds: 8
  • Max upshifts/downshifts: 1
  • Multi-position: Yes
  • Part weight: 122g
EX1 Chain

The high torque loads of e-bikes require tough components. The straighter chainline of EX1 allows the use of a chain that is wider and more robust than those found on drivetrains not specifically engineered for electric MTBs. It is a throwback that will last a lot longer than a normal chain.


This is not a new system, as SRAM looked in its braking arsenal to piece together the ultimate stoppers. Thus it is a proven system with existing components to provide power and modulation. Components are the Guide R lever with its great modulation coupled with the 4-piston caliper from the Code gravity brakes. Sintered pads and bigger rotors complete the offering. Weight is 415g (based on direct mount, 800 hose, 160mm center lock rotor)

The EX1 shifter is rear only and fires off one shift at a time.

The EX1 shifter is rear only and fires off one shift at a time.

  • E-Block cassette: $390
  • Rear derailleur: $142
  • Shifter: $48
  • Chain: $25
  • Brakes: $133 each
  • Crank: $50
  • Sprocket: $20
  • Total system cost: $941
Bottom Line

Is SRAM EX1 absolutely necessary for e-bikes? No, older systems will work. But does this provide a significant benefit? Absolutely. Bikes without this system will be at a disadvantage when it comes to performance and durability.

Something that surprised us during the test is the thought that this EX1 system might have use beyond e-bikes. Think powerful riders looking for the most robust system. And those looking for a simpler gears with bigger jumps may find this bullet-proof 8-speed with excellent chainline quite attractive, too. Well done SRAM.

About the author: Francis Cebedo

The founder of mtbr and roadbikereview, Francis Cebedo believes that every cyclist has a lot to teach and a lot to learn. "Our websites are communal hubs for sharing cycling experiences, trading adventure stories, and passing along product information and opinions." Francis' favorite bike is the last bike he rode, whether it's a dirt jumper, singlespeed, trail bike, lugged commuter or ultralight carbon road steed. Indeed, Francis loves cycling in all its forms and is happiest when infecting others with that same passion. Francis also believes that IPA will save America.

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