Milestone-Proposal:E-Assisted Bike

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Docket #:2021-14

This proposal has been submitted for review.

To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has the IEEE Section(s) in which the plaque(s) will be located agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:


Title of the proposed milestone:

First Electrically-Assisted Bike, 1993

Plaque citation summarizing the achievement and its significance:

The first 'electrically-assisted bike' was commercialized in 1993 by Yamaha Motor, for which pedaling was required, but the rider could derive battery-powered assistance to reduce necessary efforts. This type of vehicle varies in design detail, but assistance cuts out when the rider stops pedaling or when the speed exceeds specified thresholds. This vehicle is especially useful for people in hilly areas, since the motor provides assistance for going uphill.

200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.

IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.

In what IEEE section(s) does it reside?

Nagoya Section

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: Nagoya Section
Senior Officer Name: Masaaki Katayama

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: Nagoya Section
Senior Officer Name: Masaaki Katayama

IEEE section(s) monitoring the plaque(s):

IEEE Section: Nagoya Section
IEEE Section Chair name: Masaaki Katayama

Milestone proposer(s):

Proposer name: Isao Shirakawa
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):

Corporate Museum, Yamaha Motor Co., Ltd. (Address: 2500 Shingai, Iwata, Shizuoka 438-8501, Japan. GPS coordinates; N 34.7237, E 137.8780)

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. Corporate Museum, Yamaha Motor Co., Ltd.

Are the original buildings extant?

The original building of Yamaha Motor Co., Ltd. is extant.

Details of the plaque mounting:

The plaque will be displayed at Corporate Museum of Yamaha Motor Co., Ltd.

How is the site protected/secured, and in what ways is it accessible to the public?

The plaque will be displayed in a showcase placed at Corporate Museum of Yamaha Motor Co., Ltd.

Who is the present owner of the site(s)?

Mr. Yoshihiro Hidaka, President and CEO, Yamaha Motor Co., Ltd.

What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)

The historical significance on the ‘electrically-assisted bike’ is briefed as follows.

1. Historical Background of Commercializing ‘Electrically-Assisted Bikes’

Internationally, transport policy makers and urban planners are interested in encouraging cycling, given the potential to simultaneously achieve a number of goals, such as addressing congestion, encouraging a switch from more polluting modes and thereby reducing local air pollution and greenhouse gas emission, and increasing physical activity and thereby examining obesity and a range of other health issues. ‘Electrically-assisted bikes’ or 'pedelecs' are one tool that may help to achieve these goals [1]. Thus, a great number of people in Japan as well as in China, EU, India, Korea, and USA have been using eagerly all sorts of ‘electrically-assisted bikes’ since the release of the first product in 1993 [2,3].

2. Widespread Diffusion of ‘Electrically-Assisted Bikes’

The first ‘electrically-assisted bike’ released in 1993 by Yamaha Motor Co., Ltd. (Japan) was equipped with such a large low-powered motor and a bulky lead storage battery that once the battery was charged, the running distance of this vehicle managed to be extended to 20 km [4]. The business chance of this type of vehicle grew so rapidly that several big companies rushed into this vehicle industry just after the release in 1993. In order that these vehicles might be much more widespread, each time a new model was planned every possible attempt was made to miniaturize motors, update lithium batteries, reduce vehicle weights, and extend running distances. In addition, owing to the drastic progress of electric assistance capability the running distance of each vehicle had been extended to 100 km or more by the end of 2016 [3], and furthermore in 2020 the COVID pandemic brought an increased need for individualized transportation, such as ‘electrically-assisted bikes’ [2].

What obstacles (technical, political, geographic) needed to be overcome?

In the early development phase, ‘electrically-assisted bikes’ encountered a number of severe obstacles, which were overcome as outlined below.

1. Obstacles to Using ‘Electric Bikes’

In the 1890s through the 1980s, a great variety of ‘electric bikes’, henceforth abbreviated to ‘e-bikes’, each with an integrated electric motor used to assist propulsion, were steadily developed and worldwide spread. A typical ‘e-bike’ was equipped with a set of fractional horsepower motors, connected through a series of gears [2], for which the sales price as well as the running cost was rising steeply. To cope with such growing expenses, in 1993 Yamaha Motor dared to introduce into the market a less expensive ‘e-bike’, called an ‘electrically-assisted bike’ or ‘pedelec’ [1,2,3], for which pedaling was required, but the rider could choose to switch on battery-powered assistance to reduce the effort required [1].

2. Restriction to Using ‘Electrically-Assisted Bikes’

Depending on local laws, many ‘e-bikes’ (e.g. ‘electrically-assisted bikes’ or 'pedelecs') are legally classified as bicycles rather than mopeds or motorcycles. This exempts them from the more stringent laws regarding the certification and operation of more powerful two-wheelers which are often classed as electric motorcycles. ‘Electrically-assisted bikes’ (or pedelecs) are much like conventional bicycles in use and function, or in other words, the electric motor only provides assistance, for example, when the rider is climbing an uphill road or struggling against a headwind. Thus, these vehicles are especially useful for people in hilly areas where riding a bicycle would prove too strenuous for many to consider taking up cycling as a daily means of transport. They are also useful specifically for those riders who more generally need some assistance, e.g. for people with heart, leg muscle, or knee joint issues [2].

What features set this work apart from similar achievements?

The ‘electrically-assisted bikes’ have distinctive features as outlined below.

1. Sensors necessary for ‘Electrically-Assisted Bikes’

For the ‘electrically-assisted bike’ to work, pedaling is required, but the rider can derive battery-powered assistance to reduce necessary efforts, as already stated. To drive this vehicle, two different sensors are necessary; one is a speed sensor, and the other a torque sensor. The former is used for measuring the pedaling speed, and the latter for calculating the pedaling force [5]. By making the best use of these sensors, given a vehicle, both of the rider's pedaling speed and pedaling force are systematically controlled.

2. Batteries Used for ‘Electrically-Assisted Bikes’

The original ‘electrically-assisted bike’ released in 1993 used a bulky lead storage battery, whereas the newer models have been adopting rechargeable batteries, such as sealed lead-acid (SLA), nickel-cadmium (Ni-Cd), nickel-metal hybrid (Ni-MH), and lithium-ion (Li-ion) batteries, which offer lighter, denser capacity batteries [2,3]. These batteries vary according to the voltage, total charge capacity, weight, the number of charging cycles before performance degrades, and ability to handle over-voltage charging conditions. The energy costs of operating these e-bikes are small, but there can be considerable battery replacement costs. The lifespan of a battery pack varies depending on the type of usage. Shallow discharge/recharge cycles will help extend the overall battery life [2].

3. Diffusion of ‘Pedelecs’ and ‘S-Pedelecs’

As for the ‘electrically-assisted bike’ or ‘pedelec’, the pedal-assist cuts out once 25 km/h is reached, and the motor produces maximum continuous rated power of not greater than 250 watts. Owing to the realization of such ‘pedelecs’, more powerful e-bikes, called ‘S-pedelecs’ can be successfully commercialized, each of which is equipped with a motor more powerful than 250 watts and less limited pedal-assist, i.e. the motor does not stop assisting the rider even if 25 km/h has been reached [2] . These ‘S-pedelecs’ are legally classified as mopeds or motorcycles rather than bicycles and therefore may need to be registered and insured, for which the rider may have to carry some sort of driver’s license (either car or motorcycle). It should be added here that in USA many States have adopted ‘S-pedelecs’ into the ‘Class 3 category’, where e-bikes are limited not only to 750 watts or less of power but also to 45 km/h or less of speed [2].

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

[1] S. Cairns, E. Behrendt, D. Raffo, C. Beaumont, C. Kiefer, “Electrically-assisted bikes: Potential impacts on travel behaviour”, Transportation Research Part A Policy and Practice, pp. 327-342, 103, Sept. 2017.
[2] ‘Electric bicycle’;
[3] ‘Electrically-assisted bikes’;電動アシスト自転車 (in Japanese).
[4] ‘Yamaha・PAS’;ヤマハ・PAS (in Japanese).
[5] ‘Best 5 Electric Pedal Assist Bike/Bicycles in 2021 Reviews’;


References [3] and [4] are written in Japanese, for which English abstracts are provided for reference in what follows.

(1) Reference [3]: This article outlines ‘electrically-assisted bikes’ released by Yamaha Motor as well as by other providers. Concretely, the contents are concerned with the following items:
(i) Outline, (ii) Product Structure, (iii) Electrically-Assisted Bikes in Several Countries; Japan, China, Korea, and EU, (iv) e-BIKE, (v) Electrically-Assisted Bikes and Sightseeing, (vi) Remarks, (vii) Main Makers in Japan, (viii) Footnotes, (ix) References.

(2) Reference [4]: This article surveys the product of ‘Yamaha・PAS’, which is the first ‘electrically-assisted bike’ developed in 1993 by Yamaha Motor in Japan. The contents include the product name, a short history of production, an overview of the product, and references.

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).

Please recommend reviewers by emailing their names and email addresses to Please include the docket number and brief title of your proposal in the subject line of all emails.