Car fans know it by heart: this is the non-negotiable requirement for high-performance coupés and roadsters. But do you know exactly what makes RWD so desirable among sports cars? Let’s find it out!
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Why are Sports Cars Rear-Wheel Drive?
While all traction systems have pros and cons, the characteristics of rear-wheel drive make it more appropriate to sports cars than any of the others. In short, they enable them to reach the expected dynamic behavior without driving up fuel consumption or production cost.
Nevertheless, the automotive industry has never thought that nothing could ever be better than RWD, even for sports cars. It has been studied that all-wheel drive is also interesting for them but in different ways. This article is going to show you more information to help you make such a delicious decision when choosing your next car.
#1: Better Performance Under Acceleration
Forward acceleration causes the dynamic effect of transferring a part of the car’s sprung weight towards the rear axle. This addition increases its traction capacity so, in the end, a car with rear-wheel drive will gain traction the more it accelerates.
Traction capacity is directly related to how much the driver can control the car. Sports cars are designed to perform well at high speeds and intense driving styles, so they should use whatever solutions there are to excel at that. In short, RWD grants them more traction capacity the more they accelerate.
Another important factor is that this layout makes the rear wheels controllable as well – the front ones are always controllable because of the steering system, albeit in a different way.
All-wheel drive turns out to be more effective in this regard because having control over all wheels is safer than over only two. However, RWD is still the favorite option for sports cars, especially in the opinion of car fans, mostly because of the other two reasons listed here.
#2: Ability to Power-Oversteer
When engine power is high enough, which is common among sports cars, it is possible to induce oversteer on any surface. Skilled drivers may use that effect in a controlled way to take turns at higher speeds to decrease lap time or to drift for amusement purposes.
Oversteer happens when making a curve. In the regular case, the further the car’s center of mass is moved towards the rear axle, the more likely it will be to oversteer. The opposite situation makes it more likely to understeer, which is the opposite effect.
Regular oversteering happens when only the rear wheels lose traction during the curve. They tend to move along with the tangent of the curve, which means the axle starts pushing sideways. Since the front wheels are still following the curve, the rear ones tend to spin around them with a smaller diameter than that of the curve.
While this effect is dangerous when executed by accident, especially with inexperienced drivers, skilled ones induce it on purpose for the two reasons mentioned above. In general, they do it once and keep it through the whole curve when driving at high speeds to make the curve faster and do it in repeatedly alternating directions when drifting. The latter case is usually called “fishtailing”.
#3: Shorter Overhangs
With RWD, it is possible to minimize both front and rear overhangs, that is, both longitudinal distances outside the wheelbase. Having the axles close to the respective limits of the body makes the car more stable, which is extremely helpful for high-speed driving.
Sports cars do not need large trunks, so their rear overhang is naturally short. With RWD, they do not need mechanical components connected to the front axle, so there is more freedom to push it forward. In other words, the front overhang can be shortened as well.
The closer the wheels are to the body’s corners, the more mass will be located within the rectangle formed by them. That makes the car’s dynamic behavior easier to control, which is highly suitable to driving at high speeds even for experienced drivers.
What Popular Sports Cars Come with Rear-Wheel Drive?
Pretty much all dedicated coupés and roadsters. In other words, models which come from an exclusive project rather than being derived from city cars. Audi R8, Chevrolet Corvette, Dodge Challenger, Ford Mustang, and Porsche 911 are only some of the many examples of that.
Choosing between FWD and RWD implies several complex changes in the car since we are talking about changing the driven axle. Therefore, automakers frequently make this decision at the very beginning of the car’s project and only reconsider it when it is time to give it a complete update.
Some sports cars also offer AWD. In practice, the modern solution to that is to use RWD as a standard and add an electronic system to route part of the available torque to the other axle (the front one, in this case). This is the part-time AWD system, which is activated only when the car’s ECU detects the need for extra grip.
What are the Disadvantages of Rear-Wheel Drive?
When analyzed alone, they offer low capacity at low acceleration. Considering RWD with front-engine, they need a transaxle system, which increases mechanical complexity. When it is paired to the rear engine, it increases oversteering tendencies to the point of making the car unstable.
According to the previous topics, RWD gains traction capacity at high acceleration, so it has low effectiveness at typical city speeds. Even though those are not sports cars’ habitat, they still have to be considered when choosing which model to buy.
A front engine with rear traction, usually abbreviated to FR layout, implies the need for a drive shaft that extends through the whole length of the wheelbase. It cannot be placed too low because that would make it too susceptible to damage from daily use. As a consequence, it reduces the available space for the center passenger of the rear seats – some cars even remove this seat altogether.
The rear engine with rear traction (RR) layout eliminates that problem by placing the engine and driven axle close to one another. However, it also maximizes weight on the driven axle. Sports cars with RR layout end up with a higher than usual tendency to power-oversteering, as mentioned before.
The first Porsche 911 units, for example, were problematic for inexperienced drivers for that reason especially because it was designed long before the release of modern-day electronic assists.
AWD vs. FWD vs. RWD. What’s the Best for Sports Cars?
RWD with part-time AWD is the best for sports cars. Even though it looks like wishing for more wishes, that layout has become quite common among sports cars precisely because it joins the best of both worlds.
Front-wheel drive is usually associated with front-engine, so it has high traction capacity at low speeds because the driven axle supports the engine; having everything on the same region minimizes the mechanical chain, and setting the rear free of essential parts makes it easier to adapt the platform to other body styles. While those qualities are important, they are not relevant to sports cars.
Rear-wheel drive allows the automaker to tune the car’s dynamic behavior in a way that benefits performance. However, all-wheel drive maximizes the available grip, which ends up being even more suitable to performance cars when we think of safety.
As mentioned in some paragraphs above, AWD can now be offered as a part-time system installed on top of a permanent FWD or RWD layout. Rear-wheel drive with part-time AWD is perfect for a sports car because it gets the necessary amount of traction no matter the driving condition.