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Wunderlich hybrid BMW X2 in the driving report

The power of two hearts

Hybrid technology has long since gone into series production in cars, but it is still uncharted territory in the two-wheeler sector. With the hybrid BMW X2 prototype, BMW specialist Wunderlich is now showing what is conceivable. MOTORRAD was able to try out the electric / combustion GS.

VWe are all familiar with internal combustion engines. One or the other may have ridden motorcycles with electric drives, after all, a few series machines are already on the market. So far, however, nobody has dared to combine the two types of drive. But what sense would such a hybrid two-wheeler make??

Wunderlich hybrid BMW X2 in the driving report

The power of two hearts

Different solution approaches

The interaction between the electric and combustion engine is solved differently and is very much dependent on the performance of the electric motor and the battery capacity. Sometimes an electric drive is used more as a booster for short acceleration processes (mild hybrid), which in principle is also the case with current Formula 1 racing cars. On the other hand, some hybrid series vehicles with high battery capacity and powerful electric motors can even drive purely electrically over certain distances (full hybrid).

Nevertheless, one can be divided about the sense or nonsense of this technology. Because these are often models in the upper price category with large-volume combustion engines that want to adorn themselves with the cloak of environmental friendliness through the hybrid drive.

Hybrid makes sense in two-wheelers?

If it were all about reducing consumption, hybrid technology would probably make little sense in a two-wheeler. Especially since it is inevitably complex, expensive and heavy. No argument for a two-tonne car in the upper price range, but for a fraction of the price for a 200-kilo bike. But there is another aspect with the motorcycle: You could gain functional advantages if the combustion engine conventionally drives the rear wheel and the electric motor also drives the front wheel.

Which brings us to the subject of two-wheel drive. In the course of evolution, some hobbyists and tinkerers, but also well-known manufacturers such as Ohlins / Yamaha, have tried this too. However, these highly complex mechanical or hydraulic drive variants have not yet caught on, prototypes or small series have remained. Seen in this light, the additional electric drive on the front wheel would be innovative.

Wunderlich X2 intended for combined drive

This is exactly what BMW specialist Wunderlich has implemented in a prototype based on the BMW R 1200 GS. The hybrid BMW-GS X2 has the unchanged drive train of the boxer, in addition, a 7.6 kW electric motor in the hub drives the front wheel. The batteries with a capacity of around 2 kWh are distributed across the two cases. You can easily calculate that with this energy reserve you could really only drive to a limited extent purely electrically. The electric drive is very practical when maneuvering, especially since the motor can be easily switched to reverse mode using a toggle switch.

However, the Wunderlich X2 is intended for the combined drive. In terms of operation, it works like any other BMW R 1200 GS: starting, clutching and shifting – everything is normal. Seen in this way, one could actually forget the additional electric drive at the front. Only the additional controls on the tank cover distinguish the Hybrid-GS from a normal one. The electric drive can be switched on here and the maximum electric power can be limited via a controller. Whereby 150 percent means that in extreme cases the maximum current of 15 amperes can flow. If necessary, the electrical drive power can be reduced. While driving, the control together with the combustion engine is proportional to the position of the throttle.

A total of 315 kg total weight

However, the hybrid drive is not completely imperceptible; it is initially noticeable through the higher weight. The heavy front wheel including the hub motor, the batteries and the complex control electronics add up to a total weight of 315 kilograms. This is of course noticeable when maneuvering and at low speeds. Even when driving, the weight is always present thanks to the front wheel, which turns slowly due to the higher gyroscopic forces. The Wunderlich X2 drives like a heavily loaded BMW R 1200 GS. Wunderlich also had to cut the spring deflection and steering angle at the front, as the control technology had to be stowed under the duck’s bill.

But what does the driven front wheel bring? The boost effect is definitely noticeable, the electric motor mobilizes the full additional thrust for a maximum of five seconds when accelerating. It is available every time you change gears and loads, so this short period of time is definitely sufficient on the country road. When accelerating out of a curve, the hybrid drive also provides more stability because the front wheel pulls. On the other hand, the front wheel, which slows down as a result of the recuperation, brings some unrest in the steering when entering. Nevertheless, the coordination of the hybrid drive of the Wunderlich X2 looks successful.

Unfortunately only little energy gain

From 120 km / h, the front-wheel drive switches off completely. In addition, it is of no use, because its share of the total drive power becomes smaller and smaller with increasing driving resistance due to the motor power limited to around 10 HP. The driven front wheel has the greatest advantage when there is a lot of slip, for example off-road. The all-wheel drive of the Wunderlich X2 provides more traction on slippery terrain, for example when starting on wet grass.

And what about the environment? The energy gain through recuperation is very low and will certainly be eaten up again by the additional weight and higher frictional resistance on the front wheel. No wonder that the consumption on the MOTORRAD test lap of 4.8 / 100 km was within the scope of the usual measured values ​​for the normal BMW R 1200 GS. But that’s not what the Wunderlich project was about. “The idea came up sometime in the evening at the counter. We then looked for and found ways to implement this, ”explains Wunderlich’s managing director, Frank Hoffmann. Series production or further development is not considered. So the Wunderlich X2 remains a pure show bike, even if the potential of the all-wheel drive is already recognizable in the prototype stage.

Technical data Wunderlich X2

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Integrated quite inconspicuously: the electric motor in the front hub is only noticeable at second glance.

Wunderlich hybrid BMW X2

engine

  • Two-cylinder four-stroke boxer engine
  • 101.0 x 73.0 mm
  • 1170 cc
  • 92.0 kW (125 hp) at 7700 rpm
  • 125 Nm at 6500 rpm
  • Front wheel hub drive
  • 7.6 kW (10.3 PS)
  • with electric motor
  • Lithium polymer battery
  • Capacity 2.0 kWh

landing gear

  • Bridge frame made of steel
  • wishbone guided telescopic fork
  • directly hinged strut
  • Double disc brake at the front, Ø 305 mm
  • Four-piston fixed calipers
  • Rear disc brake, Ø 276 mm
  • Double piston floating caliper
  • Traction control
  • SECTION
  • Cast aluminum wheels 3.00 x 19; 4.50 x 17
  • Tires 120/70 R 19; 170/60 R 17

Dimensions + weight

  • Wheelbase 1507 mm
  • Suspension travel front / rear 180/200 mm
  • Seat height 850–870 mm
  • Weight with a full tank including batteries 315 kg
  • Tank capacity 20.0 liters

price

  • not specified, prototype

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