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Two-Wheel Drive Vs. Four-Wheel Drive

Do you really need four wheels putting power to the ground?

Text By Jason Thompson

I grew up in Minnesota, where I learned a few of the tricks to driving on snow and ice. My first lesson came when a couple buddies and I decided to take our first vehicles across an icy field after a foot of snow fell. I still remember how hilarious my friend’s gas-powered Chevy truck (with its 3-inch body lift and wide, 35-inch mud tires) looked trying to climb 5-foot-tall snowdrifts with only one front and rear tire spinning. Remember, with an open differential, if one tire has less traction than the other—it’ll spin. So even with a four-wheel-drive truck, you can get stuck with only one tire on each axle spinning.

One of the reasons I recall that day so well is because my other buddy’s front-wheel-drive Chevy Corsica was able to bust through the snowdrifts and literally drive circles around the beached Chevy 4x4. The little car had to use lots of momentum everywhere it went, but it was able to stay on top of the snow and not get stuck. Even though it was only two-wheel drive, because the car’s weight was concentrated over the driving wheels, the driver had just enough traction to keep moving.

Do We Even Need Four-Wheel Drive?
I used to have a full-time four-wheel-drive ’96 Jeep Grand Cherokee. I loved the coil-sprung solid axles and light, unibody construction. The 4.0L gas hog was another story—I wanted to replace it with a VM Motori diesel (like some European models had), but that project got put on hold. I drove that Jeep in all kinds of winter weather, and although it had a short wheelbase (which made it kind of squirrely in two-wheel drive), in 4-Hi it pulled straight through even the deepest snow banks.

After my last winter in Minnesota, I decided I didn’t need four-wheel drive all the time. So I unbolted the front driveshaft and strapped it down in the cargo area. I drove the Jeep like that in two-wheel drive all the way to Florida, then back to Minnesota, and finally to California. It was nearly two years later when I was driving on the sand dunes of Pismo Beach before I actually had to put the front driveshaft back in. Between those dates, I bet the truck got at least two more miles per gallon out of every tank, and the Jeep had a much better steering feel.

I came to the conclusion that the only time I really needed four-wheel drive was the rare occasions when I was looking for trouble or couldn’t gain enough momentum to drive through deep snow, mud, or sand.

Two-Wheel Drive Has Impressed Me
A friend of mine used to have a ’79 Chevy two-wheel-drive ½-ton pickup painted like a cow. He grew up driving all kinds of farm machinery, golf course equipment, motorcycles, and basically anything else with wheels. His driving skills were like that of Diesel Power Challenge winners Rocky Horn or Erik Clausen. When we would go wheeling, it wasn’t a surprise to see his cow truck be at the front of the pack. Two-wheel drive made his job much simpler. He never had to worry about whether he should use two- or four-wheel drive. The cow truck just went. But if he slowed down, failed to plan ahead, or didn’t trust his instincts for one instant—the cow truck was done for.

Later in life, I learned to respect two-wheel-drive trucks more and more. Some of the best off-road race trucks are two-wheel drive. Also, some of the quickest diesel drag trucks are two-wheel drive. With two-wheel drive, you have less maintenance costs and less moving parts to fail. Not to mention two-wheel drive makes everything lighter. Heck, even 4x4s spend most of their lives in rear-wheel drive—but they carry around the extra weight and capacity of a front axle and transfer case all the time.

Four-Wheel-Drive Perfection
Take a long look at Audi’s new E-Tron Quattro hybrid drive system in the R18 race car. This is the future of four-wheel drive, and Audi’s competition-tested powertrain gives us a glimpse at one of the most significant automotive technological advancements to date. Though the rear wheels of the car are powered by an impressive turbodiesel V-6, the front wheels are driven by an even more exotic electric motor and flywheel combination.

With this four-wheel-drive system, braking energy is stored in a carbon-fiber flywheel and then transferred to the front wheels when the vehicle needs to go again.

The other upside I see with this system is the elimination of the horrible driveline angle plaguing lifted four-wheel-drive pickups. Extreme traction control is also possible, but perhaps the most interesting aspect (at least for a kid who remembers messing around with cars in a field in Minnesota) is the ability (theoretically) to do a burnout with the front wheels spinning the opposite direction of the rear wheels.

By Jason Thompson
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