Pikes Peak, Colo., 21 June—Rob “Bullet” Barber, a veteran British motorcycle racer, shoots up the upper third of the mountain race course here in Pike’s Peak, Colo., with eerie silence. And that is not a good thing.
He is riding the Buckeye Current, a monstrously powerful electric motorcycle designed and built by students at Ohio State University, and the rules of the Pikes Peak International Hill Climb—being held Sunday for the 100th year running—require electric bikes to make a sound loud enough to warn errant pedestrians of their coming. This morning the noisemaker burned out, and making it work is the technical problem of the day.
“Electric bikes have to be louder than gasoline bikes are at their maximum,” grouses Aaron Bonnell-Kangas, of Columbus, Ohio, the leader of the team and a graduate student in electrical engineering.
He allows that in trying to correct what had last year been an overlarge noise maker, the team might have moved too far in the other direction. The new version didn’t have enough volume. The immediate solution was to amp up the power, but that trick worked only for a short time before a fuse—rated at 20 amps—burned out.
So half a dozen Buckeyes—that’s the nickname Ohioans give themselves—clamber over the engine compartment of their huge Ford 4x4. They finally scavenge a 31-amp fuse and install it in the noise circuit. Problem solved, for now.
The sound does rather grate on your nerves, but maybe that’s the point, suggests Polina Brodsky, a fourth-year mechanical engineering student. “Last year, we used a sound like the one made by the Jetsons’ flying car,” she says, referring to the 1960s cartoon show about a futuristic family.
Today’s run is just a time trial, useful partly for determining the order of the teams on race day, but mainly for working out bugs like this one. Today and for the rest of the week the teams will have the chance to try the lower and middle legs of the course as well. But Barber will get to climb all the way from base to summit only once, on race day.
The Ohioans’ bike shares parts with last year’s version, but there’s a lot of new stuff, particularly in the all-important battery system. Over its six years of iterations the bike has won prizes in several flat-course races, including a famous one held every year on the U.K.’s Isle of Man. But it has yet to top the field at Pikes Peak, which is very different from any other course.
Call it vertically challenged. Though the course is just 20 kilometers (12.4 miles) long, it rises 1,440 meters (4,720 feet), snaking through 156 turns, many at hairpin angles, to finish 4,300 meters above sea level. That’s hard on both the machine and Barber for a number of reasons.
First off is the thin air. When I walk 100 meters up a slight grade to the roped-off edge of the parking lot, I’m winded. And that’s just at the start of the final third of the course—the only part the Buckeyes are tackling on this, the first day of time trials. I’m told that at the finish, about 1000 meters higher still, even a slow walk on a flat grade can make you lose your balance.
At the end of one run, Barber sits on the lip of the door of a van and takes two long drafts from an aerosol-can-like oxygen flask. I ask him whether that can really make much of a difference, and he responds, “Oh, yeah!”
There had been some talk of fitting out Barber’s mask with an oxygen supply. Problem is, such a contraption would provide one more variable, one more thing that could go wrong, in a punishing race that already has a lot of them.
Barber offered his services to the Ohio team when they met a couple years ago on the Isle of Man. But last year, during his first attempt to scale Pikes Peak, he had an accident, broke his foot, and went through a lengthy recovery.
This is a competition, and if you don’t take calculated risks, the other guy will. I mention to Barber that I’d seen his leg come within a hand’s breadth of the road surface when he was leaning into one of his turns.
“It touched the ground,” he replied. I gaped for a second, then noted to him that I was a motorcycle-racing newbie. He didn’t look surprised.
The bike itself is not bothered by the thin air because its batteries need no oxygen. And that’s why the team thinks it can win not only the “green” electric category but that for motorcycles overall.
“We want to go up Pikes Peak ahead of the gasoline bike, we want to be the best,” Bonnell-Kangas says.
You might think gasoline bikes could fight back by using a supercharger to pack more air into their cylinders as they climb higher. But then you’d have to tune the engine one way for the base and another way for the summit. Not easy. So far, it appears that no bike team is supercharging this year.
To be sure, an electric bike has already won the overall category, in the 2013 race. That bike—called the Lightning—is not entering this year’s race; Bonnell-Kangas considers the Kommit EVT Zero FXS, a collaboration between MIT and Mirai, a Japanese race team, and Komatti, a U.K. team, to be his machine’s main rival this year. He says he wonders whether they’ve fully optimized their bike for this race and this race alone, as the Buckeyes have done.
Another problem on this mountain course is the variable temperature. The runs are held early in the morning, in part to precede the crowds of tourists, and at 4:45 a.m. the temperature was in the single digits Celsius (mid-40s Fahrenheit). Later on the thermometer rose to around 20 C (high 60s Fahrenheit), which we all handle by peeling off layers of clothing.
The bike, though, needs more pampering. Its motor and inverter are sufficiently temperature-sensitive to merit separate, water-cooled systems, each with its own radiator and pump. Its batteries like to stay cool. And its fat, treadless tires must stay warm.
“When they’re cold they have no traction at all, which is why you warm them to start and you keep them warm in motion,” says Bonnell-Kangas.
All the teams have special coverlets—popular here are the blue, electrically heated warmers made by Chicken Hawk—and leave them on to nearly the last minute before a time trial. To help the warmers do their job, team members throw leather jackets and blankets over the coverlets.
The final problem is having both the energy and the power you need—the first to finish the course and the second to handle all the accelerations after the many turns and switchbacks. And this is where the Ohio team has gone to the greatest lengths to match their bike to this highly vertical course.
They are using an array of lithium-ion batteries—from A123—that are tailored for power delivery rather than energy-storing capacity. As a result, they figure they can get up the mountain but maybe not down (that’ll be more of a coasting affair)—but they can sure accelerate through the many twists and turns.
“That motor can handle 200 kilowatts,” Brodsky tells a visitor from one of the other teams. “This [battery] pack could probably pull 350 kW. High power, low energy density—that’s the tradeoff we chose for Pikes Peak.”
Philip E. Ross is a senior editor at IEEE Spectrum. His interests include transportation, energy storage, AI, and the economic aspects of technology. He has a master's degree in international affairs from Columbia University and another, in journalism, from the University of Michigan.