SHOW TIME! ZERO SR/F | Tested
Zero has created a bike that will change your mind on emission-free motorcycling
In terms of performance, handling, practicality, or, frankly, plain old fun, there’s never been the basis to make a direct comparison between internal combustion and electric-powered motorcycles. But the arrival of the American-made Zero SR/F changed that.
Because after spending one-and-a-half days riding Zero’s new SR/F in every kind of situation, and growing first to respect it, then to love riding it, I have to admit it: this is the game changer. Finally, it’s showtime for a road-going electric motorcycle.
Mind you, it’s taken US$250 million (AUD$361m) of venture capital invested over the past 11 years by Zero’s owner, New York-based private equity firm Invus Group, to get the innovative firm this far. And now, with a bike like this, Invus deserves to start recouping on its investment.
Setting aside the environmental benefits, there’s always been a few factors which have deterred enthusiasts from embracing electric; besides range anxiety and recharging times, there’s always been inherent compromises in E-bike design that stopped them being genuine rivals to conventional motorcycles. Using skinny tyres to reduce drag, for example, or downsized brakes to lower weight – stuff like that. And that’s before we even mention the often dorky styling…
In other words, until now, unless you really wanted to contribute to saving the planet, there’s been no real incentive to buy electric.
In a way, it’s logical that it should be California-based Zero Motorcycles that has finally smashed this barrier down, because it essentially invented the electric motorcycle a mere decade ago with the 2009 Zero S – the first series production EV in those pre-Tesla days, beaten only by Vectrix’s maxi-scooter, which launched in 2006, before going bust soon after.
Ten years on, Zero continues to be the world’s largest manufacturer of electric motorcycles, even including China, where the millions of two-wheeled EV products sold each year are predominantly scooters. Formerly named Electricross, Zero was founded in 2006 by former NASA engineer Neal Saiki, who started the company in the garage of his Scotts Valley home. There, in what is now its 6225m² factory, Zero has continued to ramp up its range year on year, with an ongoing 40 percent annual growth rate in both the company’s revenue and unit sales – but with a surprising twist. Europe’s E-bike sales are accelerating at a greater rate than the States and is these days responsible for around 52 percent of Zero’s business.
Which is another reason why the SR/F’s arrival, which only took 30 months from blank sheet to the bike you see here, is so timely, because Zero has completely recast its lead model as a high-performing, European-styled nakedbike ready to appeal to overseas customers.
“If riding electric is a transformational experience in terms of feeling more connected to the environment, we wanted to make sure this motorcycle did that on steroids,” says Zero’s Chief Technical Officer Abe Askenazi.
To create that vision Askenazi & Co. started from zero (sorry!) – fewer than 10 percent of the components employed in the company’s previous range-topping SR model made it to the new one. Apart from the same pouch cells inside the all-new (but same size) battery box, only the pegs, mirrors, indicators, grips, ’bar endcaps, wheel-speed sensors, horn, reflectors and sidestand switch were carried over.
The battery box at the heart of the motorcycle has been totally redesigned, its cast-aluminium structure gaining vertical fins to assist cooling during charging (and stationary). There are more fins at the centre than on the edges because the pouch cells within contact its sides via thermal pads, and the cells at either end of the box inevitably have more exposure to the outside air. The denser centre fins equalise the temperature, and together with the equally important structural ridges, give an appealing look to what was previously just a hard-to-love blob of a black box.
The SR/F’s ZF75-10 brushless Z-Force AC motor created in-house represents a significant upgrade to the previous design. This is a radial flux sealed motor, whereby the interior permanent magnets are located on the single moving part (the rotor), while the components that get hottest (the windings or coils) are mounted on its periphery, so heat can be dissipated via a deeply-finned aluminium housing. This means there’s no bulky and heavy liquid cooling, since the motor is passively air-cooled, although the refined styling does feature a chin fairing that funnels air beneath the battery box to the motor positioned in the swingarm pivot, and to the controller mounted in front of it.
The SR/F’s motor is 30mm wider than before, which produces more power – no less than 82kW (110hp) at 5000rpm, and a constant 190Nm of torque. That’s quite some increase from the 52kW (70hp) and 157Nm of the SR, making the SR/F the first Zero to produce more than 100 horses. Top speed has also risen significantly to a claimed 200km/h (from 165kmh) thanks also to a 1000rpm increase in peak revs to 7500rpm.
“The extra revs give us higher power and so more speed, plus we were also able to go to thinner laminations in the motor,” says Askenazi. “This helps produce less heat, so you have as good a performance as you did before, but with less thermal loss, meaning it’s more efficient and holds power better. We can run at a sustained speed of 180km/h indefinitely in the 45ºC temperatures of Death Valley.”
By contrast, early Zeros couldn’t maintain extended 130km/h speeds without having to reduce power for thermal protection. What’s more, the SR/F was stacked against a race-prepped SR, and consistently lapped five seconds faster over a 3.2km track on a same day/same rider basis. In producing that kind of horsepower and torque, the three-phase air-cooled controller draws 900 amps from the battery pack, but to ensure the battery isn’t unduly stressed under a full load, the pack’s now been made capable of producing 1200 amps.
Wrapped around the battery pack, which it uses as a fully-stressed component, is a tubular steel spaceframe worthy of any Ducati, bolted to cast aluminium plates, which each comprise the outer housing of the swingarm. This is made from two halves of pressed steel welded together – that massive hit of constant torque was too much for an aluminium structure to support. That’s why the swingarm pivots on a 100mm diameter oil-impregnated sintered-bronze bearing, to tie everything in tight to create a solid swingarm pivot.
It encircles the motor’s drive shaft in a coaxial arrangement – which Massimo Tamburini pioneered on his first-generation Bimota designs and for the same reason – constant chain tension or, in the SR/F’s case, belt tension.
The fully-adjustable cantilever Showa shock sits offset to the right, and delivers 140mm of travel to the cast-aluminium rear wheel, which carries a 180/55-17 Pirelli Diablo Rossi III tyre that’s far larger than anything Zero has used before. It’s the same up front, where the 43mm Big Piston Showa SFF fork, which is again fully adjustable and gives 120mm of travel, carries a 120/70-17 Diablo Rosso III compared to the SR’s 110-section front hoop.
Brakes are, as on all Zeros for the past six years, provided by J.Juan, but for the first time its front four-piston calipers are doubled up and radially mounted, and bite upsized 320mm floating discs, with a 240mm rear disc and single-piston floating caliper. The need for the uprated brake package is due to the SR/F’s claimed weight of 220kg (at all times) for the standard bike, and 226kg for the Premium, with its bigger charger. This is a lot heavier than the outgoing 2018 SR at 187kg.
It also means a substantial difference between its comparable internal combustion rivals, like the 209kg Ducati Monster 1200. But the American E-Rod more than makes up for that in performance, thanks to its huge 190Nm dose of constant torque, compared to the Ducati’s 118Nm.
Like the Monster, the Zero has massive visual presence in either of the two colours it comes in – Seabright Blue (which looks green in certain light) and Boardwalk Red, which is more of a crimson. One of the few criticisms I have is these conservative shades are almost apologetic by nature – the pale aquamarine verges on anonymity.
This is a Streetfighter with a capital S, for heaven’s sake, give us a broader range of more aggressive colours to choose from, Zero. More positively, build quality and finish seems extremely high, as befits a bike that’s essentially hand-built.
Sit atop the 787mm high seat that’s 20mm lower than before, and you immediately discover a more welcoming riding position than on any previous Zero. You feel part of it, sitting in the bike rather than on it, but not wedged in place and the SR/F seems really well balanced despite its heft. The one-piece aluminium handlebar delivers a slightly forward riding stance, which is sporty yet comfortable, and not at all tiring.
I spent a good part of my second day on a series of high-speed pursuits of Zero test rider Trevor Doniak. I found the performance of the new Zero to be absolutely intoxicating, with the kind of muscular acceleration I was already familiar with after riding each successive year’s new Zero model since 2012.
This is a huge step up from even last year’s SR, let alone the Zero DSR I made a week-long 1500km tour of Northern California on without ever quite running out of charge (it was close once, though!). Of course, the new motor plays a key role here, but it’s that seamless yet controlled delivery of massive torque as soon as you open the throttle, that’s so invigorating. Sorry, Ducati – but this is a Monster 1200 on steroids and much easier to ride for the simple reason you’re always in the right gear.
Moreover, Zero has made the bike super controllable via the choice of well-defined riding modes, even if I didn’t have to worry about Rain, and wasn’t concerned about getting home, so didn’t use Eco – returning to base after 140km of hard, hard riding saw 12 percent of charge still in the ‘tank’.
In Street mode, the throttle response is quick but not abrupt, and the acceleration curve can’t be maxed out, where Sport mode does allow this, delivering phenomenal acceleration from a standstill, as one unfortunate guy on a tuned-up Harley found out when he tried to outdrag Trevor off the lights. I almost crashed, I was laughing so much!
The most noticeable difference between the two modes is the regenerative braking when you roll off the throttle. In Sport mode, the regen doesn’t kick in until the throttle’s just a few degrees from closed. This permits a more precise application, and allows you to get back on the throttle harder. In Street mode, proportional regen takes over several degrees away from completely closed, and as the grip gets closer to the full off position, the regen increases, albeit progressively, delivering engine braking which the rider can modulate as the situation requires. The only trade-off is that when rolling on the throttle again, the initial acceleration isn’t as snappy.
However, I found that descending a twisty hillside road in Sport mode, the regen kept slowing the bike as I closed the throttle for a tighter turn. And the only way to adjust it is to get on your phone and do it through the app. That’s impractical – I want to be able to alter it now via a switch on the ’bar, just as I can on BMW’s C evolution E scooter. I can switch to Street to have less intrusive regen, but then I sacrifice the more immediate hit of maximum torque I want when I get on the throttle.
But if that and the colours are all I can complain about, it’s a mark of how successfully Zero has re-invented the streetlegal E-bike. Besides the truly mind-blowing acceleration, its high-speed handling was deeply impressive, too, tracking straight and true on a short blast up to the 200km/h indicated top speed, and delivering a sense of being truly planted as I flicked it from one side to another through successive 130km/h sweepers. Top speed is limited by software, so there’s no fall off in power before the limit’s reached, you simply arrive and stay there.
The SR/F is most at home on a twisting hillside road, where that slightly canted forward riding position and the motor’s formidable torque delivery, coupled with its neutral steering, come into their own. The brakes deliver fabulous stopping power, with heaps of feel, and the Pirellis are a sound choice, too.
The superbly dialled-in Showa suspension package plays a key role in its predictability, too. The Japanese company and Zero have worked together for five years addressing the extra weight of a battery-powered motorcycle, and the result is a flawless suspension package. It ate up bumps in the middle of fast bends, shrugged off road rash under braking and gave adequate ride comfort over all surfaces. I was impressed with how well the baseline settings were for my 86kg frame – though there’s a wide range of adjustment available at both ends.
I can immodestly claim to have ridden more electric motorcycles – not scooters – than anyone else on this planet, and the Zero SR/F is the best commercially available electric motorcycle I’ve tested yet, setting a new benchmark for others to aim at. But it’s more than that. It’s a package which no longer has compromises, the new Zero is at least the equal of any conventional ICE contender in the Streetfighter category, from Aprilia’s V4 Tuono 1100 or KTM’s 1290 Super Duke R.
For the first time, Zero has produced an electric motorcycle for which no excuses are in order, which delivers intoxicating performance coupled with inherent practicality, that’s ready to be compared on equal terms with any equivalent internal combustion model. You heard it here first.