Planning to buy a 4 x 4 vehicle
Research by Ali A. Karim (Jeddah)

SUV – An Overview
The definition of a sport-utility vehicle (SUV) is becoming more & more flexible these days. There was a time when these vehicles fit nearly into a small market niche and were all built to a rather specific set of design criteria. The first models were all based upon trucks, pickup trucks that is. By taking the bed of a pickup truck, putting a covering over it & converting it to passenger use, the SUV was created.

Before too long, however, people began to discover the one asset that really enabled the SUV market to grow into what it is now. SUVs can be used for more than just work: They can be used for play. In other words SUVs are fun.

In some ways, the name "sport-utility" often leads people to believe these vehicles are something that really are not. The sport part doesn’t at all mean they offer sports car performance. No SUV comes close to that. These are large, usually heavy vehicles with a high center of gravity. Some offer reasonably good acceleration, but handling could never be described as nimble or thrilling when compared to even the lowliest of sports cars or even most family sedans. The "sport" in sport-utility refers entirely to the concept of going places (off road) other vehicles can’t.

As for the utility function, that varies depending upon the vehicle itself. In the mini SUV category, the ability to hold cargo and more than two people comfortably is largely absent. But when you move up in size, these are all shaped like station wagons and tend to hold quite a bit of cargo, & ready to go out camping for the weekend. People who aren’t interested in rugged off-road adventures, still like to have the look and feel of a rough, tough truck. With large, rear-drive passenger car station wagons now nearly gone from the market place, sport-utility wagons perform the same tasks.

Mini SUVs: Honda CR-V, Jeep Wrangler, Kia Sportage, Subaru Forester, Suzuki Vitara & Grand Vitara, Toyota RAV4 etc.

Compact SUVs: Chevrolet Blazer, GMC Jimmy, Jeep Cherokee, Mitsubishi Pajero, Nissan Pathfinder, Toyota 4 Runner etc.

Midsize SUVs: Dodge Durango, Ford Explorer, Isuzu Trooper, Jeep Grand Cherokee, Land Rover Discovery, Lexus RX300, Mercedes Benz M Class, Mercury Mountaineer, Mitsubishi Montero, Musso Ssong Yong, Nissan Patrol, Subaru Legacy Outback, Toyota Prado etc.

Full-size SUVs: Cadillac Escalade, Chevrolet Suburban, Ford Expedition, GMC Suburban, GMC Yukon, Land Rover Range Rover, Lexus LX 470, Lincoln Navigator, Toyota Land Cruiser etc.

Top 10 SUVs: (Source: Consumer Review – 1999 SUV Buyers Guide)
Each of the following categories emphasizes a particular use for an SUV. Two entries in each category have been chosen, the first one at the high end of the price range and the other towards the lower end. (US models only)

Different 4-Wheel Drive Systems: All Wheel Drive & 4 Wheel Drive systems are often used interchangeably. But while there’s a distinction between them, there is no real agreement on exactly what that distinction is. Here’s an attempt:

Part Time 4WD: This is the most basic system. It gives the driver the choice to engage or disengage 4WD at his will. If you really want to go off-roading, part-time 4WD is hard to beat. It is a simple system, less costly to buy. It is often very durable under heavy stress, but has no means of allowing the front & the rear wheels to turn at different speeds, thus causing problems to steer around a corner on pavement. When 4WD is not needed it can be reverted to rear-wheel drive for slightly better fuel economy on the road. Part-Time 4WD SUVs include Chevrolet Blazer / GMC Jimmy (some models), Jeep Cherokee (some models), Jeep Wrangler, Nissan Pathfinder, Nissan Patrol, & Suzuki Vitara / Grand Vitara etc.

Full Time 4WD: This is an increasingly common system. 2-wheel drive mode changes automatically to 4WD mode when driving conditions change. Very convenient for most drivers, but it has a disadvantage off road, it can shift power from axle to axle at the wrong time, upsetting the vehicle’s balance and causing a skid or loss of control. Full time 4WD SUVs include Chevrolet Blazer / GMC Jimmy (some models), Chevrolet / GMC Suburban, GMC Yukon, Ford Expedition, Jeep Cherokee (some models), & Jeep Grand Cherokee (some models) etc.

Permanent 4WD: A variation of Full Time 4WD. It has no 2-wheel drive mode. Always in 4WD. Permanent 4WD systems also have "High" and "Low" range gearing (i.e. 2-speed transfer box) and virtually all of these systems also have a lockable center differential for serious off-road adventures. This system is relatively costly but it does offer the best of all 4WD worlds. Permanent 4WD SUVs include Jeep Grand Cherokee, Land Rover Discovery, Land Rover Range Rover, Lexus LX470, Mercedes Benz M-Class, & Toyota Land Cruiser etc.

All-Wheel Drive: These are permanent 4WD without a 2-speed transfer box. Its totally automatic & always in 4WD mode. And if your idea of off-roading is a dirt trail, then its all the 4WD you need. But if your idea of adventure includes serious rock climbing, or towing in mud or sand, a 2-speed transfer box is needed. All-Wheel Drive SUVs include: Honda CR-V, Lexus RX300, Subaru Forester & Legacy, & Toyota RAV4 etc.

Tires: For off-road use, tires are extremely important. The proper tires can make a 2-wheel-drive SUV perform better off-road than a 4WD model with more street-oriented tires.

Locking- or Limited-Slip Differential: If you are a serious off-roader, also check if locking- or limited-slip differential is available or not. A limited-slip differential detects when one wheel is slipping and sends engine power to the opposite wheel that is not spinning. It operates automatically. A locking differential mechanically "locks" both wheels on the axle to turn together. That way each wheel gets an equal share of power at all times. But you cannot take a corner on dry pavement with a locked differential.

So! What are you waiting for?? Go and get one SUV for your family and HAVE FUN!!
Source :- Consumer Review - 1999 SUV Buyers Guide
- Petersen’s 4 Wheel & Off Road (January 2000 issue)