Do YOU Need Four-Wheel Drive?

Here’s the difficulty: there are two essentially different purposes for 4WD. One for SUVs and pick-ups is to get the best traction possible in snow, mud and on slippery surfaces as well as to be sure-footed in off-road excursions of the intentional kind.

The other 4WD (sometimes called “all-wheel drive”) is meant to give cars superior traction and better handling on dry pavement. This 4WD is the sort that appears in high-performance cars. This 4WD is indeed useful in bad weather, but the low ground clearance in most of these cars keeps them from coping with deep snow or rough stuff.

When traction control appeared I predicted that 4WD in cars would fade away because few people really “needed” it in anything but an SUV or truck. (Not even 100 miles farther north.) Of course 4WD is increasingly popular. What do I know.

But actually some of the 4WD systems (in the likes of Audi, Subaru WRX, Mitsubishi EVO) are there because the cars are front-wheel drive platforms and FWD is discordant with another trend in the automotive world - higher horsepower.

In front-wheel drive the wheels that are driven by the engine and charged with transferring power to the ground are also the wheels that are steered. Excessive power coming through the front wheels usually leads to what is called torque steer. You can feel the tugging through the steering wheel. It’s at best annoying and at worst dangerous.

It seems around 200 hp is the limit to avoid troublesome torque steer, though some manufacturers are better than others at dealing with it.  Acura’s engineers caught on early. Swedish cars (or once Swedish maybe one should day) on the contrary seem to wear torque steer as a badge of honor. I’ve felt torque steer in even 4WD Volvos. What is it with Swedes and torque steer?

A good way to cope with the problem of putting herds of horses though the front wheels is to circumvent it altogether and use 4WD. The rally-bred cars like the WRX and EVO are developing upwards of 300 HP. They have to be 4WD.

But remember, when it comes to getting a grip on the road (i.e. traction) the critical difference is not 2WD or 4WD but the correct tires. Whatever the season, whatever the weather, tires rule.

Comments:

Always enjoy your articles in Autoweek and several other publications over the years.  I
have mentioned previously I met you at Meadowdale Raceway when you were racing one of
my all time favorite cars, a Ferrari GT SWB. Long ago eh?  Anyway, I just read your coments
about 4WD and All WD.  I agree about tires. Just
put a new set of Continenal Extreme Contact DWS
tires on my ‘07 Acura TL. Replaced the factory
Michlins that came on the car at 46000miles. Biggest difference in handling I’ve ever experianced upon changing tires on any previous
car.  Wow!  Better handling and ride.

Just found this site as a link on the weekly
Sports Car Digest blog.  Best, Evert.