14 Dec 2012

Front hub motor: a sleeping force


One of the most distinct features of an electric bicycle is its motor, in both performance and appearance. There are three possible positions: in the front or rear wheel or in the middle, mainly at the bottom bracket. 

Especially the latter has come to dominance fostered by the likes of
Bosch and before Panasonic. But also the rear wheel drive has secured its position among the favored and therefore high quality and often premium priced solutions. 

First
BionX and since 2012 the German company Alber feature direct drives in the rear wheel with considerable and most of all feasible power. Even Panasonic has now introduced a rear wheel drive among others.

One wonders however why the front hub drive does not seem to benefit on the same scale by the ever-increasing variety of drive trains for electric bicycles?


Instead, it is regarded widely as the cheapest and implicitly simplest solution. Hence, front hub motors are mainly used in bicycles of rather low quality and often the engine matches the low level of the bike or is further degraded by the use of cheap and bulky batteries and a leaping motion sensor control.

There are a few exceptions to the rule, nonetheless. One is Giant who now produce their own front hub motor for their successful Twist series. (It seems likely though to be a cooperative effort with Sanyo or say some of their engineers who were set free in the latest merging with Panasonic.)
Twist Esprit
The Giant front hub drive together with their unique control runs very smoothly and enables the global company to offer a competitively priced bike range that still keeps the brand’s quality promise.

Another example is Momentum Electric a new bike brand based in London whose first two models feature a Bafang (also known as 8Fun) front hub motor. While this can be said about Raleigh or other Derby Cycle brands like Kalkhoff as well, the Momentum Electric bikes are ruled by a torque sensor unique to the company called the Autorqmatic™.

The front hub drive further boosts the company's declared mission of ‘Moving Everybody’ by keeping the price comparatively low without compromising on value. 
Model T

The design of the Model T and, even more so, the Upstart accounts for further distinction. While most front powered bikes of established brands look as though no special attention has been paid to their appearance, the Momentum models embody a vision of clarity and coolness. Obviously, the company desires to attract more design-conscious riders. 
Upstart
The motor could easily be mistaken for a hub dynamo and thus appeals to people who prefer their bike not to "scream" electric...

Another small enterprise whose success was driven by front hub engines is the German Vital Bike. They now have widened their range with the omni-present Bosch bottom bracket drive but kept their easy to handle and comfortable pedelecs with front motor that are carefully targeted. Elderly consumers in particular praise these bikes with ergonomics made for their needs like the low step through frame, comfortably upright riding position or the coaster brake which remains popular in Germany.
Vital Bike

The battery in the rear combined with the motor in the front wheel accounts for one of the most balanced systems one can find in a pedelec.

For all the above brands, the unrestrained thinking and careful alignment with consumer’s needs rather than trends or dominant technology seems to be paying off. 

So what are the true disadvantages of a front hub drive compared to other motors? 

Most front hub drives on the market are of Chinese make and though this could be said of some bottom bracket and most rear wheel drives as well - at least if you follow their production back to the roots - the factories pouring out front drives are plenty and of varying quality. 

The technology used when building a front hub drive is not too complicated. Most of them are of similar design, geared and nowadays brushless. Respectively, it is the gearing and the material of the gears that make them most vulnerable to failure as opposed to direct drives used in rear wheels which enjoy a much longer life without requiring maintenance.

Another widespread argument against the front hub drive plays on the impaired rolling or rather steering performance of the bicycle. While this might be true for heavy motors that sit in bicycles with running properties that would be questionable already without the motor, for bicycles of better quality using lighter motors a comparison with driving with a hub dynamo seems more appropriate. 

Assuming front hub drives are better than their reputation, is there some untapped potential waiting to be discovered?

Front hub motors belong to the lightest and smallest drives on the market for electric bicycles without trading too much power for reduced weight. It is in their light-weight where their biggest potential lies, especially so as weight reducing improvements seem to have not (yet) been fully explored.

Technological advances (or weight reduction) could mainly be gained in clever gearing or controlling as well as experimenting with new material- apart from accuracy in production and sourcing.
All these improvements or experiments however, require expertise and investment of money and time, which are rather scarce resources in an economy emerging with high speed. This is particularly true for China who at the same time is the main producer of these drives.

Demand and image are two more factors to take into account when looking at the seemingly less enthusiastic uptake on front hub drives by the (European) industry.

Interestingly enough, there is demand from a small group of consumers who wish to convert their regular bicycle. Those often turn to retro-fit kits with a front hub drive as it is clearly the easiest to install and often the most affordable solution.

In case of failure front hub motors can simply be exchanged and hardly stand in the way in case of a punctured tyre. The former just requires a new front wheel, the latter the unplugging of a connector.However, conversion kits, especially those of dubious quality must be seen as a critical development as their installation is not always safe nor have the resulting electric bicycles undergone any testing.

More demand from the industry for high quality or advanced front drives that could inspire innovation and investment is yet to come but might be hindered by short-sighted profit seeking that wants to keep electric bicycles in the premium segment with high margins. 
The charme of the front hub drive however lies in volume and variation. 

There is a whole segment of consumers for whom premium models around 2,000 Euro and more are simply not affordable nor attractive. That does not mean however, they would not spend a still considerate sum for the thrill of electric propulsion which a front hub drive could easily offer.

At the same time, lighter and / or easier to handle electric bicycles could attract buyers who might not have considered an electric bicycle before. Here, an aesthetic argument can be factored in - the front hub drive is the most unobtrusive of them all. 

Inventiveness and investment will be essential to uncover the front hub drive’s potential but need to be accompanied by a change of attitude. Quantity or simplicity must not necessarily come at the price of quality. Simultaneously, electric bicycles of decent quality must not stay a product only the elite can afford but can become a vehicle for inclusion.

1 comment:

  1. Anonymous17/12/12

    really, really nice and handy!

    ReplyDelete