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The ExtraEnergy Tests - There is more than meets the Eye

As an independent organisation ExtraEnergy has tested pedelecs since 1993, and over the years has developed and published a stringent methodology and measurement techniques all targeting what users really want from their pedelecs.
 

 
With the increasing popularity of pedelecs and an ever greater variety on offer, customers need ever more guidance. A test ride is certainly one of the best ways, but it is also normally the final deciding factor and it is well worth being well informed beforehand. Ever more publications include reviews of pedelecs, but it is not always clear how they were tested or which evaluation methods were employed. So the results can be all too arbitrary, especially when key figures such as range or assist power are not underpinned with well documented data. As an independent organisation ExtraEnergy has tested pedelecs since 1993, and over the years has developed and published a stringent methodology and measurement techniques all targeting what users really want from their pedelecs.

Product Categories
Most of the ExtraEnergy product categories appear familiar at first glance, drawing on ‘classic’ categories for bikes such as city or touring, as you’ll find in other publications. What is different compared to most other tests is that categorisation is not decided by the manufacturer (City-Bike xy) themselves. Instead, at the foundation of the ExtraEnergy categories are 14 customer requirements together with their importance weightings. The categories, into which around 20 years of experience has gone, are made public and are regularly reviewed by an independent circle of experts to adapt to the latest developments.

In essence, these requirements are the same for every customer and every product. Everyone wants more powerful assist, better reliability and more range. But not everything is equally important to every user, so not every pedelec needs to fulfil each criterion equally well. What matters when making a decision is who will ride the pedelec and where, and what the products needs for this.

Because the user and the intended use are closely interrelated, a little lateral thinking is sometimes required. For a Tour Pedelec it is not, as you might at first think, the range which is the most important aspect, but the ease of use. Because you have luggage with you on tour anyway, carrying a second battery as well is relatively easy. Also, most batteries are now sufficient for typical daily distances, which is recognized in the 40 km minimum range for a Tour Pedelec. Ease of use however is essential, because one of the main areas of application for a Tour Pedelec is cycle tourism. Inexperienced users need a hire bike which they can handle easily, and on which they can if necessary fix a small breakdown themselves.

Requirement Weighting
The differing requirements for the various different pedelec types are expressed through varying weightings of these requirements for each product category. To distinguish the 14 requirements clearly and to avoid arbitrary judgements, ExtraEnergy employed the ‘pair comparison’ method. So each customer requirement was compared with another, for each category. So for example we asked whether range for a touring bike was more significant than high assist power, and the responses were give values of 2 (more important), 1 (equal) or 0 (less important). Going through each requirement gave them all points, and these were summed to give the weighting, and hence the profile for that category.

The measured values and characteristics from the pedelecs on test are set against each requirement which they fulfil. In addition there are exclusion criteria and minimum requirements, for example the range of 40 km for a touring bike.

Leading up to the final test verdict, all values are entered into a spreadsheet, via which the bikes are automatically sorted into product groups, bearing in mind the exclusion criteria and minimum requirements. The weighted requirements, together with the measured values, give points for each bicycle. These are normalised from 1 to 10. This normalization also simultaneously sets the ranking, expressed as a K factor, for customer (Kunde in German) requirement fulfilment. The best bike in every group is declared the test winner and receives the top K factor of 10. All of the other pedelecs in the category are measured against this, and are awarded the seal of approval which matched their C factor.

Criteria Clarity
One decisive factor when it comes to deciding how relevant a test is, is the clarity of the criteria used. In just about every review figures are given for range, average speed, and sometimes power assist level. Unfortunately how these figures were reached is often not clear or insufficiently documented. If they are then displayed as absolute figures, and so not put into (clear) context against typical results or against other bikes (within a product category) then they lack in explanatory force. They will then need looking at very carefully indeed.

ExtraEnergy records data on the bike using special measurement equipment. Measured qualities are the speed, pedal force, pedal cadence, electrical motor power and the route profile. From this, the range, average speed and power assist factor can be calculated.

The test circuit is fixed and consists of three sections: tour, hill and city. In this way the performance of pedelecs can be determined on the flat and on various road surfaces, on climbs, and while starting and stopping. Values for each section are later given separately. If you live in the mountains, for example, pedelecs with high values for the hill section are recommended.

Normally the course is ridden in the highest power assist mode. This setting is significant, because it is easy to extend the range with more sparing use of the motor.

Range in the ExtraEnergy test is determined according to the measured use of energy. Other range figures, which depend on, for example, riding until the battery is empty, are too inaccurate, especially when data on the route height profile and power assist mode used are missing.

Particularly high average speed figures should be seen in relation to other values such as the energy use, battery weight or the charge time.

ExtraEnergy tests have shown that different pedelecs often have their own characteristic average speed. This often depends on the type, so a Cargo Pedelec is generally ridden slower than a sporty model.

Which contributes how much power, man or motor, is expressed in the power assist factor. This socalled U factor (for the German 'Unterstützung', meaning assistance) is a measured value introduced by ExtraEnergy. Assist power is often specified in other tests or in manufacturer claims. Sometimes figures of 200 % or more are quoted, but where these figures come from is seldom clear.

The U factor in the ExtraEnergy test describes the amount of power which riders gain through the drive to supplement their own pedalling. In this case the motor power given is not the electrical output, but instead the power which actually reaches the road, or which in other words is contributing to forwards motion.

To determine this, rides are first carried out on a reference bike without a motor. In this way we can see how much power the rider would need on a conventional bike, and how much will later be needed on the pedelec to reach the same speed.

A U factor of 1 means that the drive system is doubling the pedal effort of the pedelec rider, who would have to put in twice the pedal effort on the reference bike to achieve the same speed.

Other details which you will find in a test report include bike data. The specification, for example which suspension seatpost or brakes are used, is straightforward. The weight is more interesting. In ExtraEnergy testing all the bikes are weighed, as are the batteries, because manufacturer figures are often somewhat ‘best case’. In the ExtraEnergy test the weight is given under “Weight or carry-ability” and as a measured value for the evaluation. So it will be counted when it comes to the relationship between use and category of pedelec. It is particularly important when the pedelec needs to be carried, but if this is seldom or never the case then a good power assist can easily cope with an extra kilo or two.

Clear Priorities
In general, customers only see the end results of testing and then have to find their way through the multitude of test bikes. So it helps not only to know how to evaluate the results, but also above all to be clear about your own priorities.

To help, ExtraEnergy poses five questions: Where will the pedelec be ridden? Does it have to be lifted up steps? Will it transport cargo? Does it need a high tech display? And do you ride fast?

When you have clear answers to these questions, you can determine according to your own priorities which product categories are in the running, and thus get a first overview.

But before a final purchase decision is made you should have a test ride, ideally of several models on your shortlist. Test riding isn’t just absolutely essential when it comes to seeing which pedelec really suits you; it can also be great fun!

Copy: Nora Manthey, Andreas Törpsch, prepared within the EU GoPedelec! projekt: GoPedelec! Handbook (German version available)

Translation: Peter Eland, prepared within the EU GoPedelec! project: GoPedelec! Handbook (German version), Go Pedelec! Handbook in Czech, Dutch, English, Hungarian, and Italian

Picture and online release: Angela Budde

1 October 2012

Updated: 5 November 2012

 
 

Events:

21 - 23 October 2014
Munich, Germany
eCarTec, LEV Components Special Exhibition

21 October - 1 November 2014
ExtraEnergy Pedelec and E-Bike Test

29 October 2014
Merseburg, Germany
EnergyBus seminar with Hannes Neupert

7 - 9 November 2014
Tanna, Germany
ExtraEnergy Ergonomic Test

11 - 15 November 2014
Chengdu, China
Challenge Bibendum, LEV Components Special Exhibition

18 - 21 March 2015
Taipei, Taiwan
Taipei Cycle Show, LEV Components Special Exhibition

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