E-BIKE REVOLUTION
The most popular electric vehicle in the world is the electric bicycle, which has been engineered to amplify the advantages of its unpowered ancestor.
Written by Tom Gibson, P.E.
I USED TO NOT GIVE ELECTRIC BICYCLES a second thought. These battery-powered bicycles—e-bikes, as they are called—look like fully human bikes, except for the strange sight of people breezing along a street with pedals in motion but hardly breaking a sweat.
A closer inspection reveals some key differences. E-bikes have an electric motor and battery pack attached to the frame (or sometimes in the frame) for extra power. A small pad mounted on the handlebars enables the rider to control the power to the motor, and it displays the amount of charge left in the battery. Riders can apply the motor power many ways in any amount, in conjunction with the gears—all the time on flat and uphill stretches to increase overall speed or in bursts to overcome only the steepest sections of the route.
In my rides, I noticed a growing number of electric bicycles on the road, but most e-bike riders I came across were either older or had a medical condition that slows them. I know several that have extended their careers by switching to an e-bike at an older age, as this allowed them to keep riding and keep up with their buddies.
That was my impression, but that wasn’t what bicycle manufacturers see in their sales figures.
“They’re getting upward of around 50 percent of our revenue,” said Chris Carlson, director of e-bikes at Trek Bicycle in Waterloo, Wis. “It’s helping people rediscover cycling. It’s enormous.”
Murray Washburn, director of product marketing at Cannondale, a bike manufacturer headquartered in Wilton, Conn., concurred. “It’s everybody,” Washburn said. “The most rapid adoption rates are in younger folks. It’s become the de facto first case for people looking for a bike in many cases.”
Chris Dodman, a principal research engineer who started the e-bikes program at Cannondale, explains their attraction. “From an engineering standpoint, it allows you to go farther and see more in the time you have,” he said. “You can see more of the world and have more experiences, and you can keep up with people fitter than you. It’s a bicycle squared.”
Chris Carlson shows off one of his company’s electric bikes. Photo: Trek
To reduce the noise produced by the motor on its FuelEXe electric mountain bike, Trek studies the bicycle's performance in an anechoic chamber. Photo: Trek
Chris Dodman (left) is principal research engineer at Cannondale. Photo: Cannondale
Started in 1971, Cannondale originally made its mark in the bike world by pioneering frames made from large-diameter aluminum tubes to save weight. Conventional frames were made from steel tubing featuring a smaller diameter but thicker walls. It may seem counterintuitive, but larger-diameter, thinner-walled aluminum tubing is stiffer, stronger, and yet lighter than the steel tubing. Most bike manufacturers have adopted this frame design.
As it turns out, fat-frame tubes work well for e-bikes. According to Washburn, “It’s a convenient place to put the battery.”
Dodman, who studied mechanical engineering at Strathclyde University in Scotland and is now based in Basel, Switzerland, recalled the company’s long path to e-bikes. After an early attempt using nickel metal hydride batteries, the effort was shelved for 20 years.
“We started looking at e-bikes again in 2008 because battery technology and e-bikes were growing. That was when the financial crisis hit, and there were a lot of Bosch engineers without much to do. But they had a lot of experience in the power tool industry with batteries and things like that. Three guys from Bosch and three guys from Cannondale got together in 2009 and formed an agreement. From there, we went at a brisk pace, and in six months we had a rideable bike. We built the first Bosch mountain bike in 2010.”
The Cannondale Moterra Neo stores batteries in its frame. Photo: Cannondale
Early E-Bikes
1895 Ogden Bolton
On December 31, 1895, American inventor Ogden Bolton Jr. was granted what appears to be the very first patent for a battery-powered bicycle. It featured a rear wheel hub motor, with a 10-volt battery, and appears to have had a rear brake, which looks so much like the modern road bikes.
1897 HW Libbey
On December 28, 1897, H.W. Libbey of Boston, Mass., was awarded a U.S. patent for a bike that featured a double electric motor placed within the hub of the crankset axle, and the bike appears to have had a massive battery. This patent doesn’t clearly show where the riders feet would have rested.
1897 Humber Company
In 1897, the Humber Company built an electric tandem bike. Contemporary publications suggest the e-bike was used in the Bol d’Or bike race in Paris as a front pace setter. This vintage tandem e-bike has pedals and cranks, and looks like it had enough batteries to power a small house!
1898 J. Schnepf Automobile
In 1898, Mathew J. Steffens patented a rear-wheel drive electric bicycle that used a unique driving belt that went all the way around the outside of the wheel. Then in 1899, a U.S. patent by John Schnepf depicted a rear-wheel friction “roller-wheel” (shown above) that was situated above the rear wheel.
1932 Philips & Simplex
A product of Dutch industrial cooperation (thanks to Philips patents and Simplex bike manufacturing), the Phillips Simplex e-bike ran on a 12-V battery. A few years later, Phillips gave e-bikes a second go but this time teamed up with another well-known bike manufacturer, Gazelle.
1989 Yamaha
Yamaha invented the world’s first electrically power assisted bicycle. It was only a basic prototype. The 1989 PAS was an experimental electric bike introducing electric bike technologies that would eventually catch on because of electric bike motor systems based on Yamaha’s early mid-drive prototype.
THE O.G. EV
The history of electric bicycles stretches not to the 2010s or the 1990s, but to 1895. That’s when Ogden Bolton, Jr., of Canon, Ohio, patented a battery-powered bicycle with a motor inside the rear wheel hub and a battery within the frame’s main triangle, a design that modern e-bikes still use. Two years later, Hosea Libbey of Boston took the concept further by introducing a bicycle propelled by a “double electric motor” within the hub of the crankset axle, setting the stage for future e-bike designs.
In that era, bicycles were a common and popular mode of transportation, and much more reliable and affordable than early automobiles. But as the 20th century began, Henry Ford’s assembly line factory system enabled the kind of mass production that lowered the cost of automobiles, leading to their widespread adoption. While bicycles, electric and otherwise, found themselves overshadowed by combustion engines, inventors and companies continued to see the promise in the technology as something beyond exercise equipment or a children’s toy. Yamaha, the Japanese automotive giant, prototyped an electric bicycle in 1989 and introduced the pedal assist system in 1993, a concept that revolutionized e-bike use. This system transformed the e-bike experience, making it more intuitive and user-friendly.
Advancements came in sensor technology and power controls; riders could now enjoy smoother transitions between pedaling and motor assistance. And the ongoing improvements in lithium-ion battery technology that made modern smartphones and electrified automobiles possible added range and power to e-bikes.
“It started with Trek in Europe,” Carlson recalled. “The European market is way ahead of the U.S. market. We started with some simple hub-based solutions and got more serious 12 to 15 years ago. It’s been quite a long time in development.”
Today, traditional bicycle companies such as Trek, Specialized, Cannondale, Giant, and Raleigh all manufacture and sell e-bikes. They offer them in the same categories as “analog” bikes, including road, mountain, and gravel, but many also offer commuter bikes. These come equipped with fenders, fat tires, a kickstand, and a rack, all for riding to work or school, running errands, and visiting friends on city streets and trails. Many companies have sprung up that produce only commuter models, some with their own unique twists such as folding for easy transport.
“The e-bike market is kind of the wild west right now. Lots of companies coming in are fly-by-night operations,” Washburn said. And that has led to quality control issues regarding batteries.
The lithium-ion batteries used in today’s e-bikes hold a highly combustible electrolyte. That’s not normally an issue, but if the battery is damaged or overheated, the liquid can ignite. Once one battery cell overheats, the adjacent ones follow in a process called thermal runaway, and the heat and pressure soon become too much to contain, resulting in an explosion.
Such incidents have produced a challenge for the e-bike industry. Damaged batteries have been implicated in fires, some of which have been fatal. Usually, the problem stems from damaged batteries and misused charging equipment, rather than a problem with the bicycle itself.
“Fires often come from mismatched chargers,” Carlson said. “A battery management system monitors temperature, current, and the performance of the battery to make sure the cells don’t misbehave. There are more standards coming for e-bikes, especially for batteries and charging.”
The 56T (ultra bike) is manufactured by the French company LMX. Photo: LMX Bikes
CONVERSION
As an experienced cyclist, I had no need for advances in batteries or power control systems and had no problem keeping up with other riders on my analog bike. Then, about three years ago, Parkinson’s disease and scoliosis hit me. The people I rode with far outpaced me, and it became painful to ride.
In November 2023, neurosurgeons at Roanoke Memorial Hospital diagnosed my condition as Pisa Syndrome (think leaning tower of Pisa in Italy), meaning severe scoliosis was caused by the Parkinson’s. They would not work on my back until they stabilized the Parkinson’s disease, as they said the Parkinson’s had caused the scoliosis by sending erroneous electrical signals to my musculoskeletal system.
They proposed a technique known as deep brain stimulation as a way of reversing this. It involves drilling two holes in the skull and inserting electrodes in your brain. A stimulator device placed under my skin on my chest (like a pacemaker) sends electrical signals that counteract the bad ones to bring the Parkinson’s under control. In some cases, they can reverse the scoliosis, though that didn’t happen in mine. I needed spinal reconstruction surgery, which wired about half a dozen vertebrae together and screwed in a pair of rods to keep it straight.
After that, my wife and some friends convinced me to purchase an electric bicycle. And I went from a skeptic to a convert. There is an exhilaration in riding an e-bike. I climb long, steep hills easily. I can take rides I wouldn’t try even when I was healthy, and it’s nice to have reserve power at the end of a long, grueling ride and you still have a few miles left. And I can now keep up with my fellow cyclists.
Adam Mercier, co-founder of LMX Bikes, a French manufacturer of mountain e-bikes, told me, “It can level the playing field and get a lot more people on bikes and more people out on the trail.” That’s definitely been my experience.
E-bikes aren’t cheap–top-end models can cost as much as $15,000–but mine is worth it to me.
Adam Mercier, co-founder of LMX Bikes, said his company is trying to develop a category between bicycle and motorcycle. Photo: LMX Bikes
People always want to know, “How far can you go on that thing?” Most e-bikes average 30 to 120 miles on a battery charge. The range of an e-bike charge depends on factors such as rider weight, wind, hills, and how much pedal assist or throttle you choose. Pedal assist engages the motor when the rider pedals, while throttle control turns on the motor regardless.
A torque sensor built into the system senses your output and controls the motor’s power to match. This process relies on the controller to give instructions to the motor, so it supplies an appropriate amount of power. The controller determines how much power to provide by interpreting information from a cadence sensor in addition to the torque sensor.
The motor only kicks in if the torque required is less than the rating of the motor (mine is a moderate 50 newton-meters).
Another design choice involves the location of the motor itself. For instance, hub motors, including direct-drive and geared, mount inside the rear wheel hub, while mid-drive motors are geared and mount to the crankshaft at the pedals. Mid-drive motors offer better balance and weight distribution because of their location at the middle of the bike. Those advantages have made mid-drive motors the most popular design.
Most bicycle companies outsource their drive units. “We source the battery cells from different manufacturers and assemble them ourselves,” Mercier said. “We also assemble the drive units.”
At Trek, Carlson said, “We buy most motors, batteries, and electrical components outside.” Bosch supplies batteries as part of its drive systems, and Yamaha also makes drives.
Manufacturing e-bikes required a few changes to the processes and parts used for existing bikes.
“There are some additional forgings and castings for the drive system,” Dodman said, “manufacturing it so you can fit the battery down inside the tube. We developed the battery with Bosch that could be integrated into frames. That requires more tube manipulation.”
In addition, Dodman said, “We integrated larger spline and shaft sizes to handle the torque. We worked with Bosch to get the right feel of the drive.”
The electric motor for an LMX bike. The company says it can produce a peak power of 2,500 W. Photo: LMX Bikes
MARKET SHIFT
While most reputable e-bike manufacturers are established blue-bloods and rely on fairly conventional designs, Adam Mercier has taken a startup entrepreneurial approach. He went to school at Insi in France to study mechanical engineering, specializing in product development and innovation.
“I worked at different companies through the school as an intern part-time. I was building this company,” he said. “I built my own drive system, my own motor.”
Mercier built the first prototype 15 years ago using batteries he brought from DeWalt. “During engineering school, I was always building prototypes,” he said.
Mercier and his co-founders bought an existing company and sold shares a few years ago. Now they’re backed by a company that makes Formula E racecars. LMX Bikes designs and manufactures supercharged electric mountain bikes out of their workshop in Jonage, near Lyon, France.
“We tried to open a new category between a bicycle and a motorcycle,” Mercier said.
Their flagship LMX 56 has both pedal assist and a handlebar throttle with two independent transmissions. It has a chain on the pedal side and a belt on the other side. This patented double freewheel transmission system allows total independent “bicycle” and “motorcycle” modes.
Other companies are reexamining the design of their electric bicycles to take better advantage of what new technology can deliver.
Washburn said Cannondale is working on belt drives and gearbox technologies that will eliminate the derailleurs and shifters we’ve known for decades.
“Those have been coming around on non-e-bikes for a while, but there’s an efficiency loss compared to the chain-and-derailleur system. But as e-bikes get more powerful and lighter, that eliminates that drawback.”
“There will always be a place for conventional bicycles. We believe the percentages will shift heavily toward e-bikes,” Washburn predicted. “We’re betting heavily on the e-bike future. We think it’s a net positive for people and society.”
Based in Sugar Grove, Va., Tom Gibson, P.E., is a consulting mechanical engineer specializing in machine design, sustainability, and recycling and a freelance writer specializing in engineering, technology, and sustainability.
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