- The Spijker brothers' company, Spyker, unveiled its four wheel drive automobile at the Paris Motor show. The one-of-a-kind model, which is now in a Dutch museum, won a hill climb at the Birmingham Motor Club in 1906. But the car's complexity made it more than expensive than other vehicles of its era, explaining its lack of commercial viability. The Twyford Company of Brooksville, Pennsylvania made the first four wheel drive vehicles in the United States in 1906. One of these six autos that Twyford built still exists and is shown annually. The Four Wheel Drive Auto Company of Wisconsin enjoyed more success than its predecessors, thanks to contracts with the British and American armies that led to production of 20,000 of its Model B trucks during World War I. Although Mercedes and BMW introduced sophisticated four-wheel drive vehicles in 1926, the technology did not really catch on until American army ordered hundreds of thousands of Jeeps during World War II. In 1980, the American Motors Company came out with its Eagle, the world's first line of full-time all-wheel drive passenger cars.
- Four wheel drive enables vehicles to transfer the torque created by a vehicle's engine to each wheel. As a result, four wheel drive autos have dramatically better traction when carrying heavy loads or while traveling in snow or unpaved off-road settings than cars or trucks with two-wheel drive.
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In general terms, three types of four wheel drive systems are found in today's vehicles.
* Part-time four wheel drive: When engaged, this system provides trucks and sport utility vehicles with more powerful traction for traveling in difficult terrain or snowy conditions.
* Full-time four wheel drive: While retaining some competence in tough terrain, the main priority of this system is providing added stability for safer everyday driving.
* All wheel drive systems: This system is typically engineered for cars and it has become more popular in recent years. While it promotes safer, more comfortable handling and performance, this system has limited value in off-road terrain. - Full-time four wheel drive and all wheel drive systems are designed for use on all surfaces. Part-time four wheel drive should not be used on pavement because doing so can damage a vehicle's drive-train and also increase wear on tires.
- While sports utility vehicles and many other four wheel drive models are indeed designed to handle challenging terrain, few of these vehicles spend much time in such an environment. According to industry research, only about 15 percent of four wheel drive vehicle owners actually venture into off-road settings.
