Over the last decade, the top levels of motorcycle racing, both on- and off-road, have revealed that performance isn't just a function of power and weight; it's a function of control, of HOW that power is delivered. Both formats took a weight penalty to move from 2 strokes to 4 strokes, and while we can argue over politics, lap times dropped when they did. And now in MotoGP, we are seeing major advantages from engine management that not only smooths the torque curve but smooths the gaps created when the vehicle up- and down-shifts.
The same problems that Honda has spent millions on in motoGP, lumpy torque output and gaps between shifts, electric solves naturally (and for slightly less than the cost of a GP bike). THAT is why Alta went electric, the promise of superior control, balance, and traction. Electric motors have come a long way from Nikola Tesla’s laboratory in 1888, occupying everything from your smartphone to your washing machine to that Tesla Model S in the driveway. Ignoring the question of energy storage for a moment (i.e. battery vs fuel), an electric motor is vastly more powerful than a combustion motor of equal size. It also delivers that power differently, so the ways we think about and measure vehicle performance are inadequate in articulating that difference.
The bench-racer’s old standbys of power and weight don’t do a good job of telling the story of electric vs electric, let alone gas vs electric. Additionally, a collusion of English majors in marketing departments and editing rooms have conflated peak torque vs. delivered torque by repeatedly describing electrics as having “100% torque off the line.” 100% of what? If it’s the same torque as a Vitamix, I’m unimpressed. So for those of you that don’t have the luxury of being able to test ride the upcoming swathe of electric options, we wanted to deconstruct the mechanics of fast.
For this comparison, we’re taking a simplified look at a 40hp 250cc single cylinder four-stroke gas motor, the kind you’d find on a modern Lites motocrosser, and some equivalent 40hp electric motors. Read on as we break it down.
1. Typical ICE (Internal Combustion Engine) Torque Curve
With an internal combustion engine (ICE), available torque depends on where you are in the rev range, and the usable rev range is limited. 60% throttle at 4000rpm delivers a different amount of torque than 60% throttle at 8000rpm. And below 1,000 rpm it stalls out and dies.
2. Available Torque of an Electric Motor vs. ICE motor
With an electric motor, you have 100% of peak torque available at any point in the rev range. “Available” isn’t the same as “delivered” – we hear a lot of folks worried about light-switch torque delivery. What this really means is that a given amount of throttle input will always give you a consistent response, and you don’t have to “hunt” for the torque.
3. Torque at rear wheel for ICE
Torque at the crank doesn’t tell the whole story. Torque at the rear wheel is what accelerates a bike and is the curve you really want to see to understand what is fast. In response to the limited usable rev range of a gas motor, the industry developed selectable transmissions to make more rear wheel torque available at low speeds, and to increase the top speed of the vehicle. You get a layup of curves like this, where a line drawn from crest to crest to crest shows the peak 40 hp, and as a rider you are constantly shifting and slipping clutch to keep the bike up there.
4. Torque at rear wheel, ICE vs. Electric
An electric motor can have more usable range, but not infinite, so with a fixed gear ratio, the available rear wheel torque curves look something like this, with the electric having less torque off the line and a lower top speed.
5. Relationship between gearing and rear-wheel torque
Similarly as with a gas-powered motorcycle, if you gear an electric bike for better off the line performance, you lose top speed; gear it for higher top speed, and you lose rear wheel torque.
6. Alta’s Advanced Drive Tech
Alta’s motor and controller technology delivers a different curve of available torque than a typical electric motor by staying in the “constant power” zone for much longer, and revving to 14,000 rpm using an internal gear reduction to achieve conventional sprocket sizes and anti-squat characteristics. This allows the motor to be geared much shorter without sacrificing top speed and allows it to deliver more torque earlier in the rev range. Thus, compared to another electric bikes of equal peak power, Alta is delivering both more low-end torque and a higher top speed.
Proprietary, water-cooled motor housing. Made in house
7. Alta vs. ICE Torque Delivery
This also means that Alta can deliver torque in a manner very similar to a gas motor, just much more smoothly. The RedShift is designed to deliver torque like a 250cc bike that is perpetually in the sweet spot of the powerband. You’ll notice the gas bike does have a torque advantage in 1st gear, but we dare you to try to put peak torque down in 1st gear – njoy ur loopz.
Bottom line, gas motors deliver a lumpy torque curve and shifting gears upsets balance and traction, two real challenges on the trail, track, and street that electrics solve. Couple that with rapidly evolving tech on the battery front, and advanced electric powertrains can deliver a pretty incredible riding experience. Done right, electric is not an "alternative" to gas motorcycles, but a natural evolution of them.
Alta has been rabid and unrelenting about our pursuit of building bikes that will make you faster, smoother, better. This has forced us to extremes of elegance, efficiency, and technical innovation to realize the full current potential of this emergent technology, and there’s more to come in the future. We're looking forward to sharing the journey.