Yamaha has unleashed two very unusual e-MTB concept bikes at the 2023 Japan Mobility Show. The Yamaha Y-00Z MTB and Y-01W AWD have some unique features and give an insight into the technology that we could potentially see on the best electric mountain bike of the future.
Yamaha Y-00Z MTB
The Y-00Z MTB is a full-suspension electric enduro bike that appears to use a two-part clamshell carbon front triangle that is then bolted together, while the rear end may be made from a cast metal or carbon. A large battery is mounted in the downtube while the tiny silver motor is mounted above the bottom bracket where the seat tube meets the downtube.
The drive unit doesn't resemble any of Yamaha's current e-MTB motors and Yamaha hasn't offered any specs either. It looks to be considerably more compact than the current PW series so we could be looking at a potential lightweight motor to rival Bosch's Performance Line SX unit.
Instead of applying power through the bottom bracket, Yamaha has also chosen to use the idler wheel as a drive input, again Yamaha hasn't outlined the specific reasoning behind this layout. The Yamaha concept uses an 8t drive cog which is mounted in front of the lower pivot of the Y-00Z MTB concept high pivot design.
One obvious advantage is the simplicity of speccing cranks and switching between different size chainrings however, unless there is a freehub hidden in the crankset, it wouldn't be able to feature similar auto-shift technology that has recently been released by Shimano and SRAM. In practice the lack of tensioners and idler position of the Yamaha probably wouldn't work well, however, the concept of idler-driven drivetrains has already been proven by Rocky Mountain's Dyname system.
The most interesting tech is the EPS (Electronic Power Steering) which uses a magnetostrictive torque sensor, similar to the sensors found in e-MTB motors, to differentiate between rider inputs and external forces to assist with steering. This is a technology that has already been prototyped and tested on Yamaha's motocross race bikes. At slow speeds, the system should assist with steering but when speeds increase the system will act as a steering damper.
Other than the mounting points on the headtube, the system itself appears to be fully contained within itself. With development, this could mean that such a system could be retrofittable in the future.
Other interesting details include the upside-down fork and coil shock from Japanese suspension brand KYB suspension. The KYB Pro F32MT fork features a 02 Prototype decal on the crown potentially indicating this is the second prototype that they have produced.
Yamaha Y-01W AWD
Other than being extremely striking visually, there is a fair bit of tech on the Y-01W AWD. Firstly the bike is all-wheel drive, featuring a mid-drive motor powering the rear wheel and a hub motor on the front. These are powered by twin batteries and would presumably greatly improve traction on climbs, although having two motors and two batteries will add a lot of weight. The downtube battery is a 500Wh unit, there are no details for the second battery.
The Y-01W AWD also features KYB suspension short travel Pro F32 GR upside-down forks, mounted to the forks is an integrated front rack and four lights for night riding. At the back, there is a rear rack mounted to the seat stays.