What Is the Difference Between a 4X2 & a 4X4 SUV?by Rob Wagner
The differences between a 4X2 sport utility vehicle and a 4X4 are vast, and prospective buyers should consider their driving needs before deciding which type of SUV to purchase. The 4X2, or two-wheel-drive, features a drive system that transmits power to either the rear or front wheels. A 4X4, or four-wheel-drive, has power delivered to all four wheels via a transfer case. All-wheel drive is different from 4X4, and the two shouldn't be confused with each other.
Rear Two-Wheel Drive
Most North American automobiles throughout automotive history have been rear-wheel-drive automobiles. The rear-wheel-drive vehicle reigned supreme through the 1980s when automakers began switching to front-wheel drive as they made cars smaller. Rear-wheel-drive cars are usually bigger, like the luxury Mercedes-Benz or the Chevrolet Corvette. Virtually all SUVs have rear-wheel drive because it provides a better weight distribution -- close to the optimum 50:50 ratio -- than front-wheel drive does. It allows the front wheels to do the job of steering and the rear wheels to receive the engine's power and propel the vehicle. However, a two-wheel-drive SUV is only good for pavement driving, since having all wheels driven is necessary to navigate rugged terrain.
Front Two-Wheel Drive
Although front-wheel-drive vehicles can trace their history to the 1920s, they didn't fit Detroit Big Three's concept of a powerful, well-proportioned car. The fuel shortages of 1973 and 1978 forced U.S. automakers to shift to smaller cars. This required building cars with front-wheel drive that put engine and transmission at the front of the car. It eliminated the driveshaft to the rear wheels. Makers of the compact crossover SUVs embraced the front-wheel-drive concept. Crossover SUVs employ passenger car frames and suspension systems, but ride high and have the look of truck-based SUVs. Compact SUVs like the Honda CR-V and Ford Escape are front-wheel drive SUVs.
The engine of a four-wheel-drive SUV transmits the power to all four wheels via a two-speed transfer case and its drive axles. The most important aspect of the four-wheel drive is the transfer case's ability to drop into a lower gear range, to allow the SUV to navigate through winding, uneven trails, rough desert terrain or heavy snow. Older SUV models often just featured a shift-on-the-fly, or part-time four-wheel drive system. This type of four-wheel drive allowed the driver to manually shift from two-wheel to four-wheel drive without stopping and while driving under 60 mph. Newer automatic versions shifted to four-wheel drive when conditions demand it. Chevrolet Suburbans and Ford Explorers employ four-wheel drive.
All-wheel drive delivers power to all four wheels. It provides the SUV with better traction and stability, but that is about all it does. All-wheel-drive vehicles do not feature a reduction gear transfer case to shift the SUV into low gear to handle off-road conditions. It will not adequately climb trails or push itself out of soft sand.
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