In an increasingly diverse marketplace, pedelec customers and manufacturers have a multitude of drive systems to choose from. Ever more suppliers continue to add to the range on offer, although really significant market share is split among just a few suppliers.
Mid motors now seem to have become almost standard on pedelecs, even though this perception is not actually reflected in absolute market sales figures. The advantages of this type of drive are the good weight distribution and the way in which, when setting off or on hills, the motor power, along with muscle power, can be shifted to a lower gear via hub or derailleur gears. But this is also its greatest weakness: that motor and muscle forces are now both applied together to a transmission which is not designed for such loads, and so often wears out quickly.
Until 2008 Japanese suppliers such as Panasonic and Yamaha dominated the market for pedelec mid motors. Now though, Bosch sells more mid motors in Europe than Panasonic. In absolute terms Chinese supplier 8FUN is the motor supplier who managed to sell the highest absolute number of units (albeit mostly hub motors) into Europe in the pedelec sector in 2013.
Also noteworthy alongside Bosch is the German mid motor manufacturer Daum Electronic, whose product is best known under the PON house brand name ‘Impulse’ and who were the first to bring a mid motor with coaster brake to market.
A newcomer to the mid motor manufacturing field this year is Shimano, the most significant cycle component manufacturer worldwide. With their STePS they have brought their own component groupset for pedelecs to market, combining a mid motor with electronically-controlled gear shifting, so reducing premature wear due to gear shifting under load.
But there are also other, to date less well known companies active in the mid motor sector, for example Brose, ITOCHU, MPF Drive, TranzX, Ressel and ropa to mention just a few. At the China Cycle Show 2014, China’s largest cycle trade show which took place from the 12th to 14th April 2014 in Shanghai, more than ten further Asian suppliers were also exhibiting mid motor drive systems, focusing primarily on the European market. Among them were the companies BOFEILI and SHENGYI.
Hub motors: their potential is often underestimated
Hub motors are often spoken of as if they’re just for pedelecs at the lower end of the price range. But the potential of hub motors is certainly still a long way from being exhausted.
Front motors with electronic traction control are very popular with touring cyclists, because they allow steps to be scaled easily using the push assist function. Front motors have also proven themselves in the cargo bike sector, for example in the fleets of postal service providers. Well-known providers of front hub motors include 8FUN, Ansmann, Heinzmann, TranzX and Suntour, and new suppliers include keyde and Xiongda.
When it comes to rear hub motors, dominant in the marketplace are high-torque gearless motors from suppliers including BionX, TDCM, 8FUN, TranzX, Alber, ETM, Höganas, Zehus, Falco eMotors, Pengte and GO Swiss Drive. These motors are also often fitted to Pedelecs 45 and in high-priced, rather sports-oriented pedelecs. On some direct drive rear wheels, riding slowly uphill can quickly lead to overheating of the motor if the drive has been working for too long in a low efficiency speed zone. One motor which is hardly likely to suffer this embarrassment is the D-Series motor from BionX with its plastic housing, launched in 2014 at the Taipei Cycle Show, and which is already setting new standards for torque, peak power delivery and endurance under hill-climbing loads.
Direct drives also enable energy regeneration while braking to be easily implemented. Or, as with the Italian company Zehus, the hub motor can extract energy when muscle power is being exerted at maximum efficiency, and store it for later application in the form of extra mechanical power assist at moments of low muscle power efficiency. ExtraEnergy have proven in their tests that this actually works. Nonetheless, it has not caught on among other hub motor manufacturers, and its potential is widely underestimated.
Other advantages of hub motors compared to mid motors which have not to date been seen in mass production are the possibility of an all-wheel drive vehicle, and the simple electronic implementation of safety and comfort functions of the type which we have long since become used to in cars, such as ABS (antilock braking systems), ESC (electronic stability control) and TCS (traction control systems).
The future will be ever more ‘all digital drives’
In any case, the future belongs to partly or fully digital drive systems. These might, like the Toyota Prius, have a power-splitting transmission in which a proportion of the internal combustion engine power is electrified, making possible a continuously-variable transmission (with, for a pedelec, the pedalling rider taking the place of the IC engine). This system has been implemented in prototype form by the English company Nexxtdrive. A fully digital drive, in contrast, is designed without any chain or other mechanical transmission, instead using two or even three electrical machines, for example two hub motors and one pedal generator.
As part of the ExtraEnergy LEV Components Special Exhibition, at EUROBIKE in Friedrichshafen this year (27th - 30th August 2014) digital drives will be covered in the form of lectures and a round-table discussion. And at INTERMOT in Cologne (1st – 5th October 2014) a seminar on the theme of low-maintenance technologies for use in fleets and public hire systems will discuss in depth the application of fully digital drives for light electric vehicles.
Seeking a market overview
The number of pedelec drive systems on the market is huge and growing. We showcase here some notable suppliers to the European and Asian markets. Our overview makes no claims to be comprehensive.
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Text: Hannes Neupert and Isabel Wolf
Photos: Manufacturers, ExtraEnergy
28 August 2014