After getting you up-to-date with the latest on the brand new SRAM EX1 drivetrain system for E-MTBs, now it’s time to reveal how it fared on the trails.

Before we get into the review, we would like to tell you about our new print edition. Consisting of around 240 (!) pages, the 2019 E-MOUNTAINBIKE Print Editon offers a ton of inspiration, buyers advice, and eMTB know-how as well as reviews of the hottest bikes of the year. Our premium magazine is aimed at experienced eMTBers and beginners alike. Click here for more information (new window) or order it directly in our shop or on Amazon.de!

Objects of desire: the new SRAM EX1 drivetrain with an 11-48 gear ratio.
Objects of desire: the new SRAM EX1 drivetrain with an 11-48 gear ratio.

33 gears, 30 gears or even 27 gears? Forget ‘the more, the merrier’, the important question is not how many gears, but how wide is your gear range, because it is a wider ratio that gives you the ability to take on steep climbs and save battery life. The new SRAM EX1 has a gear range of 436 %, meaning an enormous ratio spread over just eight gears. Keep reading to see how it performed on the trails.

One of our test fleet: A long-travel Moustache with the full SRAM setup.
One of our test fleet: A long-travel Moustache with the full SRAM setup.

For those who haven’t yet read our article crammed with the technology lowdown on SRAM’s new EX1, we’ll once more outline the concept behind their first E-MTB-specific drivetrain system.

The issue with conventional drivetrains

  • Double shifting under the load of the motor causes snapped chains and excess wear on the drivetrain.
  • Limited gear ratio affects how E-MTBs climb and impacts on their battery life.

The solution

The E-BLOCK cassette is at the core of the SRAM EX1 drivetrain system, designed for mid-drive motors. Specifically created for E-MTBs, SRAM’s system with eight gears claims to have nailed the ultimate gear range for climbing. Impeccably symmetrical, the result is hailed as precise, defined, quiet and smooth. With the 11-48 tooth cassette creating a gear range of 436%.

Designed to exclusively shift one gear at a time, the EX1 has set itself apart from conventional mountain bike cassettes to offer more diversity in fewer gears, which should be more than substantial. Moreover, the absence of multishifting under load will add longevity to the components.

The SRAM EX1 groupset comes with X-SYNC chainrings (14, 16 and 18-tooth sprockets for Bosch motors and 34-tooth chainrings for Brose and Yamaha mid-drive motors). The wide-narrow-wide tooth profile should guarantee the chain runs securely on these ultra durable steel chainrings.

E-MOUNTAINBIKE’s chief editor Robin chatting to SRAM’s Elmar Keineke while out testing in Finale Ligure.
E-MOUNTAINBIKE’s chief editor Robin chatting to SRAM’s Elmar Keineke while out testing in Finale Ligure.

The SRAM EX1 on test

But enough theory! Prior to SRAM’s official launch, we were invited to Finale Ligure to test the drivetrain on the mass of trails (seen in the Enduro World Series) as well as relishing the opportunity to kit it out on our test fleet to ride our own diverse local trails.

Steep climbs, typical Italian charm and the warm sun: ideal testing grounds.
Steep climbs, typical Italian charm and the warm sun: ideal testing grounds.

Shifting with the SRAM EX1

Basically there are no real changes when it comes to shifting with the SRAM EX1 and it’s still down to your thumb to press the right-hand lever, emitting that super precise, defined click that we’re familiar with from SRAM’s shifters. The derailleur then shifts sprockets on the cassette – carried out super directly by the EX1, although it’s resolutely a single-shift, having designed a system that eliminates the issues of double-shifting (or even multi-shifting).

It says enough that you even find yourself shifting through gears far less often once you’ve got used to this set-up, and that’s down to the ratio between the sprockets – usually around 13 % but the new EX1 has measured them on average at around 30 %. It’s most evident as you start riding – accelerating with the EX1 just takes a few clicks of the shifter until you hit 25 km/h, which is in stark contrast to the days of multi-shifting in less than one pedal stroke.

Shifting under load? Definitely doable (although not really advised!)
Shifting under load? Definitely doable (although not really advised!)

During our testing it struck us how much of an impact the cable routing by various manufacturers has on the quality of the shifting. Down in Finale Ligure we’d ridden a Moustache test bike, and the complex cable routing around the motor meant slightly more friction when shifting – much unlike that Cube Stereo Hybrid that we kitted out with the SRAM EX1 to ride on our home trails in and around Stuttgart.

Off-road with the SRAM EX1

The new SRAM EX1 enables you to climb slower than ever. Ok, that may sound sarcastic, but the fact is that the big 48-tooth chainring just puts you at ease, no matter what lies ahead. Moreover, thanks to the higher cadence and therefore higher efficiency of the motor, there’s a positive effect on the battery life. However, no in-depth tests have as yet fully been carried out on this subject.

Thanks to the generous 48-tooth top sproket, not even the steepest of climbs will make you want to turn around and go home.
Thanks to the generous 48-tooth top sproket, not even the steepest of climbs will make you want to turn around and go home.

SRAM explained how they’d meticulously redesigned the tooth profile and this is evident on climbs as the smoothness and precision resulting from this is welcomed. Despite the big gear steps, the chain never feels like it’s tugged from sprocket to sprocket, it’s more like it gently glides up or down – even under load. What’s more, even on mega bumpy trails the chain was kept securely in place and not once dropped off.

Can the 8 gears on the SRAM EX1 hack it in the Alps?

Most riders will probably be wondering this. And our answer is simple: yes, these eight gears are more than sufficient. For one, the gear ratio hasn’t been limited by the number of gears and secondly, the gear steps – even if they seem pretty generous – have been designed wisely. With the motor on the bike, small dips in performance can easily be compensated for.

Even on the bumpiest terrain the chain stayed securely in place thanks to the level of damping from the rear derraileur.
Even on the bumpiest terrain the chain stayed securely in place thanks to the level of damping from the rear derraileur.

Wearing down the SRAM EX1

Having clocked up kilometres in some pretty nasty conditions, we haven’t yet spotted any signs of wear and tear on the EX1 components. It strikes us as pretty clever than the five biggest sprockets have been machined from one piece, making them particularly durable. The three smaller ones, which you’ll mostly use at around 25 km/h, therefore making them more susceptible to wear, can be changed individually – a tidy money-saving solution.

Machined from one billet, the new cassette is reputed to be extremely hard-wearing.
Machined from one billet, the new cassette is reputed to be extremely hard-wearing.

Can I fit the SRAM EX1 on my current E-MTB?

Right now the drivetrain is only available to manufacturers, and will be sold on E-MTBs from summer 2016. As it stands, there are some pretty impractical legal barriers for retailers to mount different parts onto e-bikes. The EX1 has been released by SRAM as Original Equipment for use on E-MTBs. So it’s down to the manufacturer of the bike to decide whether they use it on their models. If you’re in any doubt, it’s worth asking qualified specialist retailers which components are permitted to be swapped. In order to fully benefit from the EX1’s potential, unleashing its performance, the dealer will have to alter the stored gear range in the motor control to make it compatible to the big cassette if you’re fitting the EX1 drivetrain system.

Our conclusion: SRAM EX1

The EX1 drivetrain is the first important step made by SRAM towards E-MTB-specific components that have been created to withstand the demands of E-MTBing. In terms of technology and shifting performance, this system leaves virtually no wishes unmet and is a significant improvement to having conventional MTB drivetrains on E-MTBs. Bigger gear ratio, wise gear steps and a longer lifespan = a massive plus in performance and fun.

Don’t miss our article with technical details and the development story of the EX1. We’ve also reviewed the e-MTB specific Guide RE brakes.

More information on the new component on the SRAM website.


It's finally here: The 2019 E-MOUNTAINBIKE Print Edition, our timeless annual issue! Consisting of around 240 (!) pages, the 2019 E-MOUNTAINBIKE Print Editon offers a ton of inspiration, buyers advice, and eMTB know-how as well as reviews of the hottest bikes of the year. Our premium magazine is aimed at experienced eMTBers and beginners alike. Click here for more information (new window) or order it directly in our shop or on Amazon.de!

Words: Robin Schmitt, Christoph Bayer Photos: Christoph Bayer, Victor Lucas