The motor is a central functional element in the frame, so it's no wonder that it gets a lot of attention. Sometimes with undesirable consequences for bike manufacturers: Customers no longer ask for a specific bike, but for a specific motor - the bike manufacturer degenerates into an extra. In the past, a Shimano XT rear derailleur had to be attached to the rear axle of a mountain bike, but with e-mountainbikes this role seems to be taken by the Bosch motor at the moment.
Bosch recognised the signs of the e-bike early on and reacted accordingly. While others were still struggling with development or at least with teething troubles in recent years, the Swabians were able to deliver reliably. So much for the past. 2016 is already seeing greater diversity on the motor market, and the cards will certainly be reshuffled this year. Some systems - including the Bosch system - give bike manufacturers less freedom when designing the bike, with many settings and add-on parts being predetermined. Other drive systems, such as Brose, are more variable in this respect and allow independent solutions for integrating motors and batteries into the bike. There is also an increasing trend towards customising displays and own software. Software tuning in particular allows the entire characteristics of the motor to be influenced and thus the riding behaviour to be individually adjusted to the bike. In the following overview, we present the key data of the individual systems in a clear and comparable manner. Important to know: The continuous output of the motors is limited to 250 watts; the torque can be used as a guide for the greatest power. Although the battery capacity is a basic indicator of the range, the actual values often deviate from the factory specifications. That's why, in our tests, each bike has to prove in reality how far the battery can go.
CENTRE ENGINE
With the birth of e-mountain bikes, the mid-motor has quickly established itself as the
established itself as the best concept. There are now numerous systems from different manufacturers. The advantages clearly outweigh the disadvantages: thanks to integrated gearboxes, the electric motors work at high speed, which makes them highly efficient. In addition, the bike's centre of gravity is central and low, making it easy to control. Disadvantages: high chain wear, more complex technology - therefore expensive.
REAR ENGINE
Rear-wheel motors are quite common in hardtails. However, they often show weaknesses on climbs. Especially on long climbs, many systems tend to overheat or provide too little support. In full-suspension bikes, the high weight of the rear hub drive has a negative effect on the suspension performance. The rear-heavy weight distribution of the bikes is also a problem. Hub motors in the front wheel are not at all an option for sporty pedelecs due to their negative influence on the riding behaviour.
ADAPTIVE DRIVES
The market for aftermarket drivetrains is large, and there are systems that work reasonably well when retrofitted to a bike. If you are travelling off-road and also like a lot of suspension travel, you should take a closer look at the Ego-Kit. It can be quickly flange-mounted to the bottom bracket and the battery pack disappears into the rucksack. The BionX-D series makes sense for hardtails. The oversized rear hub motor doesn't run out of breath on every steep climb. Problematic: Drives that go faster than 25 km/h are illegal in open terrain.
A market overview of the current E-MTB drives can be found below as a PDF download:
- Bionx D-Series
- Bosch Performance Line CX
- Brose e-bike system
- Cleanmobile - TQ
- Impuls EVO RS Offroad
- Panasonic Inter 2
- Shimano STEPS E6000
- Yamaha PW
Stephan Ottmar, EMTB test manager: If you want to do ambitious mountain biking with an electric drive, a fully with a permanently installed mid-motor is a must. On good bikes, the performance of the chassis is right and all the components fit together. The problem with retrofit systems: The normal frames are often not designed for a drive unit, and the question arises: Will the bike be able to withstand the loads permanently? In the past, hub motors often weakened or failed completely.
