Yamaha two-wheel drive motorcycle

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Two technologies can be used to transmit power to the front wheel of a motor cycle: mechanical or hydraulic. On a car, the power is transmitted mechanically to the wheels by driveshafts but from an engineering viewpoint, a motorcycle is essentially a "two-dimensional" vehicle, and to transmit power to the front wheel isn't easy. The situation is complicated by the fact that a hub of front wheel on a bike is surrounded by the forklegs, and in certain cases by double discs, making the hub even more difficult to reach.

The majority of the prototypes constructed by Front wheeland Yamaha used a mechanical drive by chain or gears connected to the front wheel. These systems were found to have many disadvantages: they were heavy and complex and required high maintenance. Another problem associated with mechanical systems is that fitting them required complex modifications to the frame and suspension.

By comparison, an hydraulic system is relatively simple, light, compact and discrete: it is for all these reasons that YAMAHA and 'hlins chose the hydraulic system. On a conventional rear-wheel-drive bike, the rear wheel patters on loose surfaces and the engine power is not completely transmitted to the ground through the rear wheel. By diverting 15% of the power to the front wheel, the 2-Trac system decreases the power loss from lack of rear-wheel traction and offers better overall traction. Another advantage of the 2-Trac system is that it easily adapts to any machine without requiring large changes to the engine or frame. For these reasons, Yamaha is convinced that a hydraulic system is the best for motorcycles.

What does it feel like to use?

The 2-Trac represents one of the most significant developments on the off-road scene for many years, and its potential impact can be compared with that of the first 4x4 off-road cars. "While riding with the WR450F 2-Trac, you will be surprised by its capacities and its performance in the most difficult situations as sand or mud," according to Jean-Claude Olivier, President of Yamaha Motor France and one of the main test pilots in the development program. " The WR450F 2-Trac motor bike passes where the a standard WR450F digs in," he said."In addition to excellent traction on wet or poor surfaces, the 2-Trac system also offers improved straight-line stability as well as in corners.

You turn into the corner and the rear end of the bike follows the same trajectory as the front wheel. This is quite different conventional enduro bikes where you must battle with the rear end. In the turns, the WR450F 2-Trac is easier to control, and that represents an unquestionable advantage for both beginners expert riders " The tests also revealed that the corner speed of the WR450F 2-Trac is 10% higher on the sandy tracks thanks to its increased traction. The 2-Trac will be produced for competition motorcycles only at this point, but Yamaha has been very keen to point out that the current 2-Trac system has enormous potential to be used on motor bikes or scooters in the future.

Yamaha has already noted in its pres release that the system is easily adapted to existed machines, and the press release specifically mentioned the possibility of the system being fitted to the Yamaha R1 road bike and the T-Max scooter.Yamaha Australia is planning to import a limited number of the machines and the company is buoyed by the reports from Yamaha Europe.

No price has been set for the WR450F 2-Trac but Yamaha has indicated that the price will not be substantially greater than that of a standard WR450F.

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