The coming of the electric motorcycle

The Symetron motor is 8 inches long by 12.5 inches in diameter and weighs just 67 Kg. This small size combined with high torque yield a torque density of 35 Newton Meters per Liter. Raser believes this to be the highest torque density for any drive system available today.

High torque is a critical performance requirement for an electric motor in automotive drive system as it provides the power needed to help accelerate the vehicle. Previously it was thought that the use of costly permanent magnet material was necessary to achieve the high-torque density needed for such an application.

Power-to-weight

Read our story on the Leblanc Caroline and Mirabeau cars and you’ll see that the secret to rapid acceleration is not brute horsepower but a good power to weight ratio. Lowering the weight has the same effect as increasing the horsepower, with a range of ancillary benefits. Electric motors don’t offer a big weight saving in a car, particularly with the weight of batteries to be considered. The lighter the batteries, the more expensive they are, or the shorter the range.

But a motorcycle already has a big power-to-weight advantage to begin with and if you’re prepared to put up with a modest range, the light weight of an electric motor can offer a compelling performance package. A motor of the ilk of the Symetron P2 motor is not required to produce startling performance from a motorcycle, and there are already several examples of this.

The Electric Moto Blade

Electric Moto Corporation builds an electric motocross bike named the Blade which delivers horsepower roughly equivalent to a 250 four-stroke motor but with much more torque low in the rev range. The interesting thing about the Blade, apart from its terrific performance and complete lack of noise or pollution, is that the controller can be programmed and hence the power curve can be tailored to suit a rider’s abilities. Unfortunately, the Blade is not street legal but it’s well worth keeping an eye on.

Perhaps the most interesting work in the areas of performance motorcycles is being done by Todd Kolin of Electric Motorsport in Oakland California.

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