Front vs rear-wheel-drive -- the war rages

By T. Uncle

The battle has been raging for decades and it still rages today, although one side appears to be slowly getting the upper hand.

Like most battles, it is a case of conflicting belief systems and, also like most battles, each side believes fervently it is fighting for a just cause. The only just cause.

The battleground is the new-car market, and the spoils for the winner -- once again the driving inspiration behind most combatants in most battles -- are world domination.

And so we introduce the contestants: On one side we have the believers in rear-wheel drive as being the only true way of configuring a motor vehicle's driveline, while on the other, we have the ongoing revolution started by the front-wheel drive believers a long time ago, but which has only become a real force in the last two decades.

The lines are drawn, and the fighting is intense, and any assessment of who might be winning is clouded by the difficulty of determine what "winning" in this case actually means.

It is almost an issue of quality versus quantity. Examining new-car sales figures anywhere around the world will give the clear indication that front-wheel drive has the battle won.

In sheer numbers, front-wheel drive is clearly way ahead of rear-wheel drive as the most popular choice of new-car buyers.

This has come about not just because the buyers wanted it: front-wheel drive has been adopted by carmakers for other reasons we will go into a little later.

Rear-wheel drive, on the other hand, appears to be gradually losing ground as carmakers say they intend to include more front- wheel drives in their future plans.

The stumbling block -- for the front-drive fraternity -- is that carmakers at the prestige end of the market, where development and engineering costs are fixed by different criteria than those used for the mass market, steadfastly put their faith in rear-wheel drive.

So who is right and who is wrong? Is there, in fact, any right and any wrong?

The answer, as always, appears to be that both systems have their positives and negatives.

Proponents of rear-wheel drive say their configuration has better inherent chassis balance than a front-drive system: the weight of the drivetrain -- engine, gearbox and differential -- is spread more evenly over the length of the vehicle.

The result is that chassis engineers have a sound base to work on when developing the car's handling and ride comfort characteristics.

It can be made to respond more easily to the steering because there is no particular design "quirk" to overcome.

The issue of under or oversteer comes up here.

Understeer means a vehicle will have a tendency to go straight ahead when asked to go around a corner at any reasonable speed.

Oversteer is the opposite: the car will tend to tuck into the corner more tightly -- sometimes much too tightly, resulting at best in a tail-out attitude, at worst in a complete spin in which the car swaps ends.

The reasons for this can be best illustrated by comparing a front-wheel-drive car, with most of its mechanical weight over the front wheels, with the now-rare breed of rear-engined rear- drive cars that had most weight over the back wheels.

The front-wheel-drive car tends to behave like a lead-tipped arrow -- straight and stable -- but reluctant to change direction, while the rear-engined car is more like a ball at the end of a piece of string. It likes to spin.

Those who recall the rear-engined VW Beetle will remember the trouble drivers had on wet roads, or any other conditions that put vehicle stability to the test.

The rear-drive car with the engine in front is nowhere as prone as the early Beetle design, but you get the idea.

Improved understanding of suspension dynamics means that even a rear-engine, rear-drive configuration can be extremely stable these days, as witness the latest Porsche 911.

The same applies to front-drive designs: today, most front- drivers have little or none of the plowing understeer that afflicted their very early predecessors.

The fact, however, is that even a very basic front-drive design will always tend to behave more predictably than a front- engine, rear-drive design.

Most drivers can come to terms with a car that at least is heading in the direction the front end is pointing; not so easily coped with is a tail-out slide, or spin where most drivers find their reflexes are being taxed way beyond normal capabilities.

Of course, these are extreme conditions, most drivers will rarely get to experience them and, depending on the sophistication of the suspension, the levels of controllability will vary enormously.

So, in reality, neither side scores a convincing philosophical win here.

The trump card, for the front-drive design, is the packaging factor.

Because of the compact design allowed by front-drive configurations, having the entire drivetrain at the front of the vehicle means there is more space, within a given overall length, for passengers.

Most front-drive engines are installed crosswise across the front of the car, therefore taking up little of the overall length.

And, because there is no driveshaft going to the back wheels, there is also more opportunity for maximizing floor space.

Having no differential, to power the back wheels also means more freedom in the design of the boot area, while bulky items such as the fuel tank can be more easily located to minimize intrusion into usable space.

Rear-drive stalwarts, such as Mercedes-Benz and BMW, maintain that the better weight distribution optimizes comfort and handling and since "optimum" is a vital word in their design briefs, they see no other way of maintaining their premium images.

Front-drive is a compromise that doesn't befit their market.

Others, such as Saab, or Honda (with its Legend model) don't see any reason why front-drive can't offer the luxury market a handling balance comparable to rear-drive, along with unquestioned packaging efficiency.

Many are taking a bet both ways: Lexus has its rear-drive LS400 and GS300 models, as well as the front-drive ES300, Audi has its front-drive and four-wheel drive models, and Volvo its rear-drive, front-drive and all-wheel drive models.

But, for the mass market -- the high-volume Toyotas, Mitsubishis and Mazdas -- front-drive rules.

The days of the rear-drive small car were over long ago.

The winner?

Not so long ago it depended on what you were buying -- rear- drive was the natural choice in the prestige market, front-drive the common denominator in the smaller, mass-market cars -- but now, even the luxury buyer is faced with a choice.

In the end, the car-buying public will declare who is the victor, although the buyer, more often than not, usually gets what the carmaker thinks is best...