Customer Review: Sram EX1 Drivetrain

Sram's EX1 drivetrain is the world's first drivetrain system specifically designed for the demands of an electrically assisted mountain bike. EX1 is born from Sram's 1x systems and featured an 11-48 tooth 8 speed cassette, designed for more purpose driven shifts. In this review, one of our customers Robert talks about his experiences using the EX1 drivetrain. Let's hear his thoughts. 

Before any ebike lip curling commences, I'm 66 and being able to do rides that I could do in my twenties is a pretty sweet thing. Over time, that will probably become self-evident.

The glowing online reviews of the EX1 are what sold me on this drivetrain: 11-48 case-hardened gears, 8 speeds better suited for electric-assist and an eight-speed chain that can better withstand the increased torque. I also got a kick out of a video of one of Sram's German engineers explaining the reasoning behind the design. It was obvious but they had just analyzed this thing to death.

But it was the 48 tooth big cog that really caught my eye. The 36 tooth cog that came with the bike just couldn't go slow enough on steep ascents which, in turn , drained a lot of amps from the battery. Now, steep climbs feel much more controlled and I get back home with more volts on the meter.

The reviews I have read all mentioned the EX1 drivetrain was designed to shift while under power but the benefits of this failed to penetrate my cranium. With my old 10 speed drivetrain , I'd reach a hill , calculate the number of gears I'd have to go down , tap the brake to pause the motor , then shift while gently pedaling. This routine never failed to cancel momentum.  Now, I just pedal until the cadence becomes too slow then shift and, voila, no loss of momentum and no excess thinking which is always a good thing. All in all, just a more intuitive, fluid approach.

The shifter only allows one shift at a time (no scrolling) and I'd say about two-thirds of the time it accomplishes this quietly. The rest happen with a kind of clunk vaguely similar to the sound a motorcycle transmission makes when going from neutral to 1st. I assume this occurs because (I don't understand this) Sram designed the sprocket so the chain only fits in one position. But it's a mechanical sound not a disturbing, gear grinding noise.

I really enjoyed my experience with the guys at Worldwide Cyclery who have the rare combination of competence and goofiness. They also had the best price out there.