Why Rear-Wheel Drive For Sports Car Better
Jun 18 '00 (Updated Sep 15 '00)
So you decided to buy a sports car. Unless you buy it just to look cool, you care how it drives. Rear wheel drive should be your first choice then.
Rear wheel drive provides better handling through better weight distribution (front wheel drive cars tend to have irregular weight distribution, i.e. 60/40, where most part of the car's weight will affect front wheels. That's why front wheel drive cars tend to understeer.
Rear wheel drive cars have better weight distribution since driveshaft, rear differential and power transferring rear axle add weight in back. RWD cars have better handling in turns and sometimes provide "fun to drive" element with oversteer.
"Too much torque" situations
"Oversteer" happens usually in rear wheel drive cars, when in turns the rear part of the car looses traction (too much torque applied through the rear wheels) and slides towards outside of the turn ("fishtailing").
"Understeer" happens primarily on FWD cars, when in turns the front wheels lose traction (too much torque through the front wheels) and slides towards outside of the turn.
When the car is entering a corner, it is good to have some understeer to provide the stability while the driver is easing off the brakes. In the middle of the corner, the neutral steer is preferred. And in the exit from the corner, a slight oversteer is needed to help to tighten the path. The degree of oversteer should be easily controllable by the throttle - "Power Oversteer". This is a type of handling the RWD cars usually provide.
If the car understeeers in the turn, you have to lift off the throttle and slow down. In RWD car, if the car understeers in the turn, you can increase the throttle (not before the mid corner!) and car will start oversteering, correcting the trajectory.
So In a FWD car, you lift of the throttle, have to slow down, the engine loses revs, so it takes some time for it to come to the full power again, and you may not have sufficient road ahead to slow down in tight corners.
Also keep in mind that during acceleration, front of the car lifts and rear wheels get more weight. That's why front wheel drive car's wheels may start to spin, yet the RWD car's rear wheels will get better traction.
"Torque steer" happens in FWD cars when the steering wheel during hard acceleration tends to turn (usually to the left) by itself. It happens because the drive shafts in FWD cars don't have the equal length like the RWD siblings do.
The all wheel drive, of course is better than RWD and FWD in terms of traction and control, but:
1. It's more expensive
2. Weights extra
3. Increases fuel consumption
AWD does not produce power oversteer (neutral handling). Most people prefer it simply because it provides superior cornering grip improving cornering speed.
People argue, what is better: RWD's power oversteer or AWD's neutral steer. AWD provides better cornering grip, but does not provide the "corrective power oversteer" capability.
All this is based on general assumptions though. Some AWD cars are biased towards power oversteer by splitting power unequally, forwarding more power to the rear wheels, or special suspension geometry. These cars combine the best of both worlds.
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