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The side view of the gray-and-white UMC 'XP Zero' Zero SR/F on a rear-wheel stand

Zero and Exro Prove You Can Tune Electric Motorcycles

For the most part, custom shops haven't touched electric motorcycles' drivetrains. But Canadian tech company Exro Technologies just showed that its Coil Driver controller can boost a Zero Motorcycles SR/F's horsepower, torque, and top speed without messing with the motor or battery.

Adding more power to a motorcycle isn’t necessarily easy, but it’s been refined and industrialized over decades of work. At least that’s the case with internal-combustion bikes. Production electric motorcycles, on the other hand, are still new on the scene in comparison. So, for the most part, builders focus on mechanical things like styling, suspension, handlebars, handling, and so on. But with help from Exro Technologies, Zero Motorcycles may have just opened up a path into two-wheeled EV tuning.  

Exro Technologies wants to give electric motorcycles better energy management

A black-and-silver Exro Technologies 100-volt Low Voltage Coil Driver electric motor controller
Exro Technologies 100-volt Low Voltage Coil Driver electric motor controller | Exro Technologies

Vancouver, Canada-based Exro Technologies doesn’t manufacture electric motorcycles, though it is involved in the EV industry. The tech company focuses on energy management using a blend of software and hardware. For example, its Battery Control System uses special software and a proprietary inverter to turn old EV batteries into an ‘Energy Storage System.’ This gets some extra mileage out of the degraded packs before they get recycled.

While extending battery packs’ usable lifespans is impressive, Exro’s other product, the Coil Driver, is more relevant to performance interests. Available in 100-volt Low Voltage and 800-volt High Voltage form, it’s a plug-and-play replacement for an EV’s original electric motor controller. Basically, it’s a swap-in ECU for an electric motorcycle, car, truck, or even commercial vehicle. And its killer app is Exro’s proprietary ‘Dynamic Power Management (DPM)’ software.

The Coil Driver helps electric motorcycle motors work smarter and harder

Here’s how this works. The Coil Driver, like all electric motor controllers, is an inverter that turns direct current (DC) from the battery to alternating current (AC). This AC powers the motor, and varying its frequency lets you accelerate and decelerate. However, with DPM, the Coil Driver gains a second function: virtual transmission.

Now, EVs don’t really need multi-gear transmissions because they make torque from zero RPM and rev much higher than ICEs. And that’s thanks to the stator/rotor arrangement at the heart of all EV motors. But by its nature, the single gear is a compromise between acceleration and top speed, which often means EVs run out of steam at higher speeds.

You can get around this by altering the connections between the stator’s metal coil windings, aka its poles. So, you have one pole profile for low-speed situations and another for high-speed ones, RideApart explains. However, this pole/coil switching momentarily disrupts the current, so power and torque output suffer. With DPM, though, Exro’s Coil Driver can effectively switch pole profiles on the fly. That way, you get instant torque around town and more speed on the highway. It’s the same thing an ICE car transmission’s gear ratios do.

And because the Coil Driver virtually eliminates current disruptions, it doesn’t just smooth the motor’s performance. As Exro demonstrated with its recent Zero Motorcycles collab, the inverter improves it.

The Exro Coil Driver kicks one custom Zero SR/F into overdrive

The side view of the gray-and-white UMC 'XP Zero' Zero SR/F on a rear-wheel stand
UMC ‘XP Zero’ Zero SR/F | Untitled Motorcycles
UM XP Zero with Exro Coil Driver2022 Zero SR/F Premium
Horsepower125 hp110 hp
Torque162 lb-ft140 lb-ft
Curb weight481 lbs500 lbs
Top speed142 mph110 mph (sustained)
126 mph (max)

In 2020, custom shop Untitled Motorcycles collaborated with Zero to create a special SR/F dubbed the XP Zero. While UMC gave the electric motorcycle a new look and cut some curb weight thanks to copious use of CNC-milled aluminum, it didn’t touch the Zero drivetrain. But after UMC teamed up with Exro, the tech company swapped the XP’s stock inverter with its 100-volt Coil Driver but left the motor and battery alone. And the results speak for themselves.

Admittedly, there is a caveat to the specs in the above table. Exro claims the Coil Driver boosted the SR/F’s horsepower by 25%. However, its website quotes a lower stock horsepower figure–94 hp–than Zero and the new claimed horsepower figure is more like 14% above Zero’s official figure. We’ll reach out to Exro regarding this discrepancy and update this article if we learn more.

[UPDATE 2/24/2022: An Exro Technologies representative confirmed that the XP Zero the company tested produced 94 hp at their test facility. Furthermore, the Coil Driver did boost the final total output to 125 hp, which is a 33% increase. The representative also informed me that the company will update its website and promotional materials to reflect this.]

Regardless, the Coil Driver improved the Zero motorcycle’s performance across the board. It makes more horsepower and torque and has a higher top speed. And keep in mind, the SR/F still has its OEM motor and battery pack.

Can you buy this performance for your own bike?

If you want your own XP Zero, UMC will happily build one for you. The shop hasn’t released official pricing details, but know that a donor 2022 SR/F starts at $19,495. Exro’s Coil Driver-equipped bike, though, is a one-off proof of concept.

However, the Coil Driver isn’t a prototype—you can buy one from Exro right now. Theoretically, any custom motorcycle shop could get its hands on one and start tweaking a customer’s bike. And as noted earlier, the tech should work just as well on electric cars, trucks, and SUVs.

So, someone might recreate Exro’s XP Zero with their own Zero motorcycle. But even if that doesn’t happen, Exro, Zero, and UMC just showed that you can tune electric motorcycles.

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