SRAM Powertrain motor is a game changer

Regardless of how it performs, the new SRAM Powertrain motor means the bike industry has more of a one-stop-shop than ever before when it comes to speccing their e-MTBs. Shimano should be worried.

SRAM Powertrain in a nutshell

• 90Nm torque
• 680w peak power
• “Best in class derating” (heat vs. power loss)
• 720 or 630Wh battery
• 250Wh range extender (only compatible with 630Wh main battery currently)
• Two power modes: Range and Rally
• Automatic shifting ability
• ‘Bridge’ display in top tube
• Operated by wireless AXS Pods
• Weights: drive Unit 2.9kg, 630Wh battery 3.1kg, 720Wh battery 4.1kg
• Debuting on various Nukeproof, Propain, Transition and GasGas e-MTBs round about… now
• Will be available with both removable and permanently mounted batteries

Now that it has finally released a whole e-bike system, the House of SRAM can now offer a ‘speccing menu’ to bike brands of: motor, battery, drivetrain, brakes, fork, rear shock, ShockWiz, TireWiz, Flight Attendant, wheels, dropper post, handlebar, stem… just about the only thing SRAM can’t supply is tyres. Yet.

With Shimano seemingly lagging behind a bit in the e-bike stakes of late – with Bosch winning over the full power bridge and Fazua/Specialized/TQ catering to the mid power market – all eyes are now very much on the Japanese giant. It feels like Shimano needs to come out with something pretty special, pretty quickly.

Anyway. SRAM Powertrain. What is it? And how does it perform?

What is SRAM Powertrain?

To be blunt, it’s a Brose motor with a few tweaks. To elaborate, it’s a Brose motor with a new belt, new heatsinks and heatshields and wholly incorporates the wireless SRAM AXS ecosystem.

Powertrain also offers automatic gear shifting. Which a lot of people may like (consistent cadence-rs or total newbies). The more interesting – and useful – feature offered is the ability to manually change gear whilst coasting. Yes, kinda like Shimano Auto Shift does. This feature was instant hit with me. Totally brilliant in fact.

I’d be lying if I didn’t come out and admit that the final unveiling and (brief) test riding of SRAM Powertrain was rather underwhelming. I don’t really know what I was expecting though!

At the end of the day, SRAM Powertrain is as good as full-power e-bike motors with big batteries get. What’s not to love? I guess I was just hoping for something genuinely new or unexpected. As it is, my relatively brief, definitely muddy 11km ride on SRAM Powertrain just felt an awful lot like riding a Specialized Levo specced with AXS Transmission. Which is fine. Great in fact. Of all bikes to be like, an AXS Transmission Spesh Levo is very good choice!

I’m iust being a spoilt brat bike journo who wanted something else. Something more. What’s the meme? “Oh dear. How sad. Nevermind.“

How does it perform?

Perfectly.

To be frank, the first half of the test ride was entirely consumed with the novelty of Autoshift. When I realised I wasn’t paying any attention to the actual motor, I disabled the Autoshift function so I could stop being distracted by it, and could focus on the motor. (I’ll get on to Autoshift later)

To get to the verdict inasmuch as I have one, I very much liked the SRAM Powertrain motor. It definitely has the power.It isnit silent but it isn’t overly loud or whiney. And ultimately, the assistance is less enthusiastically/jerkily delivered to you compared to a Bosch Performance Line CX (my personal favourite motor).

We’ve gone over AXS Transmission drivetrain stuff before. Twice. First with the X0 version and then with the GX version. To remind you of our general gist: it will never ever (EVER) mis-shift, but it’s a bit slow and makes some alarming clang noises now and then.

AXS Pods

In terms of the user interface, I had no trouble getting used to the two AXS Pod controllers. Again, I need to state that this was a very brief test ride and this was the set-up that the bike came with. Other AXS Pod set-up combo can be different. But this is what I had.

The left hand Pod’s top button swaps between the two power modes (Range and Rally), the lower button actuates the AXS Reverb dropper post.

The right hand Pod does the AXS drivetrain stuff. The top button shifts to harder gears. The bottom button shifts to easier gears. This is when you’re not using Autoshift. It works just like AXS drivetrains have done for the past few years.

Automatic shifting

Autoshift though. This is where it might get confusing to you when it’s written down in words on a webpage, but in real life it was pleasingly logical and intuitive. There’s some press-and-holding of Pod buttons to do, but I got the grasp of it pretty quickly.

Ultimately, once you’ve turned Autoshift on (by press-and-holding a Pod button) you don’t have to touch the right hand Pod ever again. The system shifts up and down for you based principally on your cadence. You can tweak the system’s ‘cadence response’ (my term) ie. you can tell it what sort of cadence-pedaller you are. If you’re a spinner, you can nudge the system to change gear to keep you in high cadence. If you’re a grinder, you can nudge it the other way and tell it to keep you in slower cadence.

Autoshift works. It does what it says on the tin. But I don’t think it’s for me. Sometimes I like to spin, sometimes I like to grind. I have no cadence consistency! And I think a lot of people may be spinners on climbs but are grinders on descents. As it is, Autoshift didn’t seem to be great at dealing with this disparity of cadence. For some people, Autoshift may unleash a whole new level of just-riding-and-enjoying-things. Which is great.

Coast shift

What is undeniably brilliant about a by-product of Autoshift is that you can change gears without pedalling. SRAM call this ‘Coast Shift’. Even with the actual automatic shifting of Autoshift turned off, you can press the buttons to change gear whilst coasting, and it changes gear. How? Basically, you press the button, the chainring whirrs around (without the cranks moving at all) and the rear mech moves the chain up/down the cassette.

This feature really is one in the eye to the gearbox brigade. With SRAM Powertrain you can change gear whilst coasting AND you can change gear whilst putting heavy pedal loads through the system. No gearbox can do that, from what I’ve tried anyway. Sure, we still have a rear mech dangling off the back of our bikes but SRAM AXS Transmission mechs genuinely are bananas-ly rugged.

It was this shifting-while-coasting that was by far the best thing about my time using SRAM Powertrain. The motor does what good motors do. The automatic shifting left me cold. But shifting whilst freewheeling? Genuinely useful on the trail and beautifully executed here.

Pod control crib sheet

SHORT PRESS (PRESS AND RELEASE):
R1: Shift rear derailleur outboard
R2: Shift rear derailleur inboard
L1: Switch between Range and Rally modes
L2: AXS dropper actuation

LONG PRESS (PRESS AND HOLD):
R1: Auto Shift On/Off
R2: Auto Shift adjustment
L1: Hold for Push Mode
L2: AXS dropper actuation

The display

Just a quick note on the top tube ‘Bridge’ display. Although it isn’t the same as those found on Specialized e-bikes, it was similar. It’s fine. Clear. Bright. It has a bit of colour to it which I do find useful for confirming selections etc compared to monochrome displays (such as TQ). I didn’t get chance to have a go at configuring it differently (via the SRAM e-bike app) so I’m not going to say anymore just now.

Having a mess about with the app would also reveal what level of tweakery you can do to the Range and Rally modes too.

SRAM Powertrain product gallery

Hannah’s 2p

Hannah: “This was my first time on SRAM’s Eagle Transmission system, as well as a first ride on the SRAM Powertrain motor system. Unless you were an early adopter of the Eagle Transmission, there’s every chance you’ll be in the same boat as me. I’ll caveat everything that follows with a note that this is very first impressions based on a very brief ride…

“The display is nice

“The top tube display seemed to me to strike a decent balance between clarity and info, although you do have to look down to look at it. And it doesn’t tell you the time.

“The motor is not really the point

“It’s a Brose motor, as has been used by Specialized for many years. It’s had a few minor adjustments for the SRAM collaboration, but it feels and sounds much the same as any other Brose. It’s the way it’s deployed within the ‘Powertrain’ system that gives it different characteristics. If you were hoping for some sort of whole new feat of engineering on the motor front, this isn’t it.

“It’s very different on the thumbs to AXS.

“The controls are completely different. I’m sure it’s possible to get used to them, but if you love the AXS paddles then you might be sad about these buttons. I found that I did get used to the tap/long press options pretty quickly, which is perhaps testament to it being all nice and simple. I am invariably useless at technology, this did not confound me.

“It’s very different on the thumbs to other motors

“There are only two assist settings: Range and Rally. Which means you use a single button to toggle between the two of them, rather than an up and down button. In some respects I quite like the simplicity of this. But…

“There are only two assist modes

“Ride and Braaap. Range and Rally. I dunno… I quite like three options. Yes you can use the app to adjust the amount of assist each of the two modes gives you, but I hate using apps (see techno-uselessness above). Some sort of economy assist where you’re trying to get the most miles out of the battery as possible can be useful, especially if you find yourself far for home having used a bit too much oomph elsewhere.

“I think there is more to be discovered

“The Transmission system comes with Autoshift, which feels disturbingly like you’ve got a stiff link when you first experience it, until you get used to the fact it’s just shifting for you. Your right thumb twitches, a bit like when you jump on a singlespeed. Autoshift has a cadence sensing element to it, which has a Mid and then +/-3 setting to it. I suspect once you’ve really got to grips with the system, you could effectively add extra assist modes by using the cadence modifications on the fly: Range(with more spinny legs)/Range(with less spinny legs). That might be a bit like unlocking one of those secret power moves in Tekken.

“Or you could turn lots of it off

“It would be very easy to just ride the bike as a two-mode ebike with shifting that didn’t care about the fact you’re crunching your way up a hill after descending in your hardest gear. With all the optional/extra clever adjustments kept to a minimum, it could be a very point and ride experience. For a beginner, or perhaps someone losing dexterity in their hands, all that reduced faff could add up to an improved ride.”

System overview

• AXS Bridge Display
• Pod Controllers
• Eagle Transmission
• SRAM Drive Unit
• Speed Magnet and Ring
• Battery
• RangeExtender (optional)
• AXS App
• Head Unit
• Rockshox Reverb AXS

sram.com

Dear Bike Industry, make this e-bike

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