The Future of Mx?
The Future of MX?
ROUNDUP
Giving "plug-and-play” new meaning
ELECTRIC MOTORS AND MOTOCROSS are a great fit. San Francisco-based startup BRD is deep into development on its RedShift electric motorcycles and hopes to join the plug-in MXer party next year. With the latest lithium-ion batteries and electric-motor technology, power isn’t an issue for electric vehicles; cost and range are the real hurdles. In an application like motocross, where gas tanks typically hold only 1.5 gallons or less and have a limited range, an alternative such as electric power starts to look like a competitive option.
The project started three years ago, when veteran Northern California racer, machine-shop owner and BRD Chief Technology Officer Derek Dorresteyn had a ç1iance to ride another company’s prototype electric off-road motorcycle. He was immediately enchanted with the smooth and torquey power delivery, even if there wasn’t much else he liked about the bike. Convinced he could do better, he launched a project to build his own electric bike. Dorresteyn enlisted mechanical-design consultant Jeff Sands to help. Almost everything would have to be done from scratch to function in the proposed application.
At the heart of the RedShift MX (Motocross) and SM (Supermoto) are custom three-phase PMAC high-voltage electric motors weighing about 10 pounds. Such a motor has rare-earth magnets on its rotor, with stationary coils to spin them. A high-speed motor like this can make plenty of power, its main limitations being thermal. Having the coils on the outside, rather than an inductive rotor, allows better cooling. The motor fits into a casting that serves both to route liquidcooling to the coils and to form the rear structure of the chassis.
Prototype motors have been benchtested by BRD over the last year, along with the 5.2-kWh (kilowatt-hour) battery pack that will eventually power them. The company is quite confident that peak output will be at least 40 horsepower, with a continuous power rating of 25 hp. The goal is to be competitive with 250cc four-strokes in the Lights MX class.
Chassis geometry and stiffness have been modeled from Honda’s CRF450R, while suspension will likely come from a premium European supplier. “There are decades of development in motocross and supermoto chassis,” said Dorresteyn. “We chose to harness the best of that while taking advantage of the torque and throttle response an electric motor delivers.”
Interestingly, the first two versions to be sold, the SM and MX, will be street-legal, with a race kit offered to convert them for pure off-road use. Why? Tax breaks and other government incentives for purchasing electric vehicles apply only to streetlegal machines. If the bikes are ridden in a suburban or urban environment, the 5.2kWh pack should give a range of about 50 miles. “We expect people to ride the snot out of these in a way that hasn’t been possible on previous electrics,” says BRD CEO Marc Fenigstein.
A prototype fleet is scheduled to begin testing in October, and small-scale production is expected in 2012. Pricing will be initially higher than all but the most exotic dirtbikes, but that may be at least partially offset by lower maintenance costs in the long term. —Steve Anderson
