Yamaha Unveils AWD and Electric Power Steering for Concept E-Bikes
‘All-wheel drive’ for motorcycles is not a new idea – but motorcycle expert Yamaha now looks to extend the concept to the bicycle world.
If driving all four wheels of an automobile has advantages, it seems sensible that driving both wheels of a motorcycle or bicycle also would offer certain performance and/or stability enhancements. Two-wheel drive for motorcycles has been attempted numerous times by many manufacturers — albeit with few genuine production-run examples — but it took the comparatively recent advent of electric assist to make the 2WD concept possible for pedal bicycles, or e-bikes.
Yamaha revealed in mid-October leading up to the 2023 Tokyo Mobility Show a 2WD concept bicycle called the Y-O1W AWD. It is targeted at the expanding “gravel bike” segment, featuring models more offroad-capable than a conventional road bicycle but less dirt- and trail-ready than a full-blown mountain bike. For electric mountain bikes (eMTBs), the company also intends to reveal a prototype electric power-steering (EPS) system.
Hub motor for front drive
Yamaha, which in 20004 marketed one of history’s handful of production 2-wheel-drive motorcycle models with its WR450F 2-Trac, offered on its website previewing its products for the 2023 Tokyo Mobility Show a few scant details for the Y-O1W AWD concept bicycle. “This adventure eBike combines a center-mounted electric motor and a hub motor at the front for two-wheel drive,” the company said. “Coordinated electronic control of the two motors, twin batteries enabling long-distance rides, wide tires and more give the Y-01W AWD excellent off-road performance and it is a concept model that points to the many potential spheres of riding open to eBikes,” Yamaha continued.
There is no indication regarding whether Yamaha intends to bring the Y-01W AWD to production, but the company does have an established lineup of ebikes, including those in the gravel-bike segment as well as the electric mountain-bike (e-MTB) market, where 2WD presumably might provide a significant boost to performance and reduction of rider fatigue.
To now, e-bikes have been the most prominent application for hub motors, which also are proposed for 4-wheeled vehicles given the design and propulsion-arrangement flexibility they present. The preponderance of current e-bikes use hub motors, but at the rear wheel only. The use of bicycle rear-wheel hub-motor layouts has been preferred for its comparative simplicity and adaptability to existing bicycle models, as well as for cost advantages.
Yamaha’s short-lived 2-wheel-drive WR450F 2-Trac used an Ohlins-developed hydraulic drive to power the front wheel, highlighting the primary challenge of nearly all 2-wheel-drive motorcycles prior to the electrification revolution: how to connect the power from an internal-combustion engine to a front wheel suspended away from the engine itself and that must remain free to steer and accommodate radical suspension movement.
Philadelphia, Pennsylvania-based Christini Technologies currently offers AWD motorcycles and conversions. Rochester, New Hampshire’s Rokon, which made its first 2WD motorcycle in 1958 also currently makes 2-wheel drive motorcycles and claims to be “the world’s original and longest producing manufacturer of all wheel drive motorcycles.”
EPS – for bicycles?
In addition to the 2WD Y-01W AWD, Yamaha also said it will display at the Tokyo Mobility Show its Y-00Z MTB, a somewhat conventionally styled eMTB fitted with an electric power-steering system. The Y-00Z MTB is equipped with a center-mounted or “mid-drive” motor but not a front hub motor.
Yamaha said the EPS borrows from technology developed for its existing e-bikes. “Based on a “Yamaha Motor Off-Road DNA” concept, this is a technical showcase of what is possible with eMTB technologies,” Yamaha said. “It combines a split arrangement for the drive unit with an Electric Power Steering (EPS) system employing a magnetostrictive torque sensor proven on our PAS line of electrically power-assisted bicycles,” the company continued, adding, “The result is both excellent handling and stability in off-road riding.”
The “split arrangement for the drive unit” refers to a small drive sprocket from the motor positioned above the pedal sprocket rather than integral with it. The company did not elaborate on what advantage this layout may provide.