Are Fwd Cars Overall Superior To Rwd Cars?

[Alberto Michelatti]

I am a FWD cars enthusiast, and I would like to explain why for me FWD cars are overall superior to RWD cars and, from a certain point of view, to AWD cars also.

1) the engine and the gearbox overall mass directly over the front axle means at the same time more brake power, more control, more directionality, more safety, more space, more stability, more traction.

2) the absence of the RWD longitudinal propeller shaft means at the same time less fuel consumption, less noise, less pollution, less space waste, less vibrations, less weight (up to about 100 kg).

3) with a FWD car, if you apply full throttle when cornering the car becomes understeering and the worst thing that can happen is that the car go straight, colliding longitudinally with the obstacles (take a scale car model and lock with adhesive tape the front wheels, make it run on the floor, and see what happens. Then lock the rear wheels and then all the wheels, and see what happens). Furthermore, on a FWD car generally only the wheel with less grip spins, while the other wheel keeps the directionality. With a RWD car, instead, the car become oversteering and the worst thing that can happen is that the car fishtails, colliding transversally with the obstacles. With an AWD car, instead, understeer and oversteer limits are obviously higher, but if you exceed them the car control recovery could be very problematic for a normal driver, because over a certain limit the car understeer with the front axle and oversteer with the rear axle, all at the same time.

4) a FWD car is very easy and instinctive to control, because if when cornering the FWD car becomes understeering you have just to release the accelerator pedal and, eventually, slightly adjust the trajectory. A RWD car is very difficult and not at all instinctive to control, because if when cornering the FWD car becomes oversteering you have to carefully keep pressed the accelerator pedal and quickly countersteer to keep the trajectory. The behaviour of an AWD car is generally quite similar to an FWD car, but when you exceed its high limits the control recovery could be problematic for a normal driver.

Briefly, I think that the overall best possible solution today available is a FWD car with an open differential, better if with TCS (Traction Control System: electronically controlled artificial limited slip differential actuated by brakes) and ASR (Anti-Slip Regulation: electronically controlled power modulation actuated by the drive-by-wire throttle). Why an open differential? Simple: just because with an open differential while one wheel spins the other wheel can keep the trajectory.

I think that the only real disadvantage of a FWD car is that it is not funny to drive, because the rear wheels are almost always perfectly on their ideal trajectory, short of you use some

like for example the handbrake 180° turn or the Scandinavian flick (pendulum turn). However, it is neither funny to bring your RWD car to a bodyshop for the reconstruction of the rear end, it isn't?

I think that the only two possible rational solutions are FWD or AWD; however, I think that a RWD car makes sense only in presence of huge power, rear engine and, most of all, in presence of very skilled drivers. I think that if you don't live in a territory with very slippery steepy roads, an AWD car is substantially useless... a waste, from a certain point of view. For example, I think that on a snow covered road it is safer to drive a FWD car with M+S tires rather than to drive an AWD car with normal tires.

And now, the curiosities corner.

Did you know what is the most powerful FWD car ever? As far as I know, the most powerful FWD car ever is the existing Pontiac Grand Prix GXP, equipped with a 303 hp SAE net 5.3 V8 engine (307 hp DIN, EU-spec).

They who say that the most powerful FWD cars ever are the 1966÷1970 Oldsmobile Toronado W-34 7.5 V8 (455 in³) and the 1970 Cadillac Eldorado 8.2 V8 (500 in³), both with 400 hp SAE gross (open exhausts, no accessories), are wrong, because when in 1972 there was the SAE gross to SAE net switch, the advertised power of the Cadillac Eldorado, for example, was of 365 hp SAE gross or 235 hp SAE net, while the power of the Oldsmobile Toronado fallen from 350 hp SAE gross to 250 hp SAE net (to convert DIN horsepower to SAE net, simply divide the DIN number by 1.0139).

For the ultimate, I think that the annoying and not dangerous FWD cars' torque steer issue, mainly noticeable on high torque FWD cars, is not depending by the half-shafts length, but instead it is depending by the overall torsional stiffness of the left-side half-shaft and of the right-side half-shaft, no matter if the equal length half-shafts or the unequal length half-shafts system is used. I think that when full torque is delivered by the differential to the half-shafts, the longer half-shaft, due to its weak torsional stiffness, accumulates a delay in torque delivery to the right-side wheel, and this phenomenon makes the car steer to the left-side.

FWD-FTW! Safety first!

Alberto.

[houston]

the engine and the gearbox overall masses directly over the front axle means at the same time more brake power, more control, more directionality, more safety, more space, more stability, more traction.

under acceleration weight moves to the rear of the car causing less grip on the front wheels causing less power transfer and slower acceleration, under braking all the weight at the fron will cause the car to nosedive and cause slower decelleration, torque steer also ruins your more directionality theory, but i'll agree there definately more safe

the absence of the RWD longitudinal propeller shaft means at the same time less fuel consumption, less noise, less pollution, less space waste, less vibrations, less weight (up to about 100 kg).

rwd is actaully more fuel efficient, just think next time your moving a chair, is it easier to pull it or push it? same principle in cars, but yeah less space waste but its space under the car that you dont need anyway

fwd are are good for daily drivers but if you want a sports car the its got to be 4 or rear wheel drive, everyone always goes on about how rwd cars are more dangerous round corners but a fwd car has understeer at slower speeds than a rwd car has traction issues, its mostly driver error thinkin they can just plant the throttle mid corner, i never had any trouble with my mr2 and even driving it in snow i had no issues, yet my calibra sacred the livi9ng daylights out me at every corner, just didnt want to turn, and that was with non standard slip diff fitted!!!

[Flat Pack]

Ok I'm bored... I'll bite ;)

1) the engine and the gearbox overall masses directly over the front axle means at the same time more brake power, more control, more directionality, more safety, more space, more stability, more traction.

Just plain wrong I'm afraid. Consider the concepts of weight transfer and tyre grip circles and you'll find that a FWD car with a front mounted engine, gearbox and diff has less traction, less braking ability and less cornering grip than a RWD car with a front engined, gearbox, propshaft and rear diff. That in my mind immediately makes it less safe.

In an acceleration situation we want as much weight as possible over the driven wheels, to aid traction. As soon as you accelerate, you transfer weight towards the rear of the car. This increases traction for a RWD car and decreases it for FWD. The static weight distribution of a FWD car will be further forwards than a RWD one, but not by enough to compensate for the weight transfer effects.

When braking you want the wheels as evenly loaded as possible, as the brakes can act on all 4 wheels. Braking transfers weight forward, loading the front wheels more and the rear ones less. As a FWD car has the weight further forwards to start off with, you'll end up with a greater imbalance between front and rear wheels and less overall braking ability. The relationship between tyre loading and grip isn't linear, so you want to keep the weight over front and rear wheels as balanced as possible when making use of all four tyres.

Finally cornering. In simple terms a tyre has a finite amount of grip available. That can be used for cornering or accelerating / braking, or some combination of both. In a FWD car if you're accelerating through a bend you're using some of the grip of the front wheels to accelerate, hence less is available for steering. In the RWD case you use the grip of the rear wheels to accelerate and the front wheels to steer, a much better situation. Under braking, the FWD car has to have more front brake bias because of its further forward weight distribution. So for a given deceleration the front tyres on a FWD car are working harder to slow the car down than on a RWD one, so again less grip is available for steering.

2) the absence of the RWD longitudinal propeller shaft means at the same time less fuel consumption, less noise, less pollution, less space waste, less vibrations, less weight (up to about 100 kg).

True, I'd be concerned about a propshaft that weighs 100kg though :o I've got an entire front engined, rear wheel drive car that only weights 540kg.

The rest of your points seem to be based around having less grip making you drive more slowly and hence more safely. If that were true, surely we should all buy the cheapest tyres we can find? On the road you should never be unintentionally in the situation where the handling characteristics of the car actually matter. If I make a mistake / misjudgement I'd rather have a more capable car and be further away from the car starting to handle than be closer to that limit and have it handle in a 'nicer' way. That way I can make a mistake and think to myself 'oops that was a bit quick / close / whatever' rather than have to deal with a skid situation, be that front, rear or all 4 wheels sliding. If you're intentionally reaching the limit handling, then you have to assume that you know what you're doing and are able to control it in either case :) If you're regularly reaching it unintentionally then you probably need some more lessons in how to drive.

[Hou]

What he /\ said!

[ObsidianGT]

Alberto,

I just created an account to specifically call you an idiot!

Here's a neat post I found on another forum:

Why Front-Wheel Drive Sucks: Car/s*x metaphors are unavoidable, so let's get right to today's: Front-wheel drive cars are like bad s*x. Rear-wheel drive cars are like good s*x.

Let me explain!

Sometime in the early 1980s, I asked my friend Paul why he drove a crass Chevy Camaro. He said he liked the "balance" of a rear-wheel drive car. I nodded but secretly sneered at him. Everyone knew that front-wheel drive cars were the efficient, sophisticated wave of the future. Audis were front-wheel drive. Saabs were front-drive. GM, Ford, and Chrysler were about to embark on a massive shift to front-drive, resulting in the current Detroit product lineup, in which even the venerable Caddy DeVille is a front-drive car.

The advantages of front-wheel drive (FWD) seem self evident: By avoiding the need for a driveshaft connecting the engine in front with the rear wheels, front-drive cars save space. The entire drivetrain can be packed into a neat compartment in the front, leaving the rest of the car's volume for passengers and cargo. Plus, front-drive cars have better traction in slippery conditions (in part because the weight of the engine is on top of the wheels that are providing the power).

I should have realized the grim truth decades ago when I borrowed a friend's Audi 100 –- the first front-drive car I'd ever driven -- and took it out on Sunset Boulevard. In one of the curves leaving Beverly Hills, near the pink house that used to be owned by Jayne Mansfield, I mashed the throttle, expecting the satisfying "lock in" effect I got in my old rear-drive Volvo – the nose turning in, the car seeming to stop slipping, tightening its grip on the road even as it went around the corner faster. But that's not what happened. What happened is the front tires went all gooey and the car started to head for the living room of a nearby mansion. Only panicked braking calmed things down.

Naturally, my brain did what the human brain tends to do with a bit of aberrant data: I ignored it. All during the '80s and '90s the car magazines assured me, seemingly continually, that in sophisticated front-drive designs you couldn't even tell which set of tires was providing the power. Weren't front-drive Hondas the hippest cars around? Wasn't even Volvo switching, belatedly, to front drive? I also blamed the victim! I must just be a lousy or unsophisticated driver, I figured.

Then, a bit over a year ago, I conducted an abortive test drive of five convertibles. The idea was to sample cars that had at least a semblance of a rear seat. The entrants were Ford Mustang, Chevy Camaro, VW Cabriolet, Chrysler Sebring, and Toyota Solara. And that was the order of finishing (though the test was interrupted by 9/11 before I could drive a final production version of the Toyota). None of the cars was very good – you give up a lot in chassis stability when you chop off the roof, I discovered. But the old, junky, rear-drive Ford and Chevy pony cars were by far the most enjoyable – they rattled and guzzled, but at least they were a blast to drive around corners. The other three cars, all front-drive, were simply pleasant forms of transportation.

Why are rear-drive cars more fun? Every enthusiast may know the answer, but I didn't. So I called up a helpful GM suspension expert, Vehicle Chief Engineer Ed Zellner. There are, I learned, five basic reasons:

1) "Balance": The car rides on four patches of rubber, each about as big as your hand. An ideal car would distribute its weight evenly, so each tire had to bear the same load, and none would give way earlier than all the others. The ideal weight distribution, then, would be split about 50/50 between front and rear (actually, 48/52 to help with forward pitch during braking). "A rear-drive car can typically approach that," says Zellner. Engineers can move the front wheels forward, so that the engine – which doesn't have to be connected to those wheels -- sits behind the front axle. Meanwhile, the driveshaft and rear differential (necessary to send power to the rear tires) add weight in the rear. Front-drive cars, which must connect the engine and transmission to the front axle, typically have their engines mounted way forward and can't do much better than a 60/40 front/rear weight distribution.

2) Center of Gravity: This is the point the car wants to "rotate around" in a turn. On a rear-drive car, it's "about where the driver sits," says Zellner. In a turn, in other words, the car seems to be rotating around you – you're at the center. It's a natural pleasant effect, suggesting you're in control, the way you're in control when you're walking or running around a corner and your weight is centered inside you. (Analogy No. 2: It's like wearing stereo headphones and having the sound centered between your ears!) A front-drive car, in contrast, with its massive front weight bias, wants to rotate around a point in front of the driver. So in a corner, the driver isn't just rotating around his spine. He's moving sideways, as if he were a tether ball on the end of a rope, or Linus being dragged when Snoopy gets hold of his blanket. Not such a pleasant feeling, or a feeling that gives you a sense of natural control.

3) "Torque Steer": One of the most annoying habits of many powerful front-drive cars is that they don't go straight when you step on the accelerator! Instead, they pull to one side, requiring you to steer in the other direction to compensate, like on a damn boat. This "torque steer" usually happens because the drive shafts that connect the engine to the front wheels aren't the same length. Under power, the shafts wind up like springs. The longer shaft -- typically on the right -- winds up a bit more, while the shorter left shaft winds up less and transmits its power to the ground more quickly, which has the effect of pulling the car to the left. (This winding-up phenomenon occurs the moment you step on the pedal. After that, the wind-up relaxes, but "torque steer" can still be produced by the angles of the joints in the drive axles as the whole drivetrain twists on its rubber mounts.)

Engineers try various strategies to control this veering tendency, but even designing shafts of equal length (as in all Cadillacs) doesn't completely solve the problem because the engine still twists a bit in its mounts and alters the angles of the drive shafts. True, some manufacturers -- Audi, for example -- are said to do a particularly good job of repressing torque steer . But even a top-rank company such as Nissan has problems -- its otherwise appealing new front-drive Maxima is said to be plagued by big-time, uninhibited torque steer. Rear-drive cars, meanwhile, don't really have a torque-steer problem that needs repressing. Their power goes to the rear through one driveshaft to a center differential that can a) have equal-length shafts coming out from it and b) be more firmly mounted.

4) Weight Shift: Suppose you just want to go in a straight line. What's the best way to get traction? Answer: Have as much weight over the driving wheels as possible. Front-drive cars start with an advantage -- but when any car accelerates, the front end tips up, and the rear end squats down. This transfers weight to the rear wheels -- away from the driving wheels in a FWD car but toward the driving wheels in a rear-drive car, where it adds to available traction. In effect, the laws of physics conspire to give RWD cars a bit more grip where they need it when they need it. (This salutary effect is more than canceled out in slippery, wet conditions, where you aren't going to stomp on the accelerator. Then, FWD cars have the edge, in part, because they start out with so much more of their weight over both the driving and the turning wheels. Also, it's simply more stable to pull a heavy wheeled object than to push it -- as any hotel bellhop steering a loaded luggage cart knows. In snow, FWD cars have a third advantage in that they pull the car through the path the front tires create, instead of turning the front tires into mini-snowplows.)

5) "Oversteer" and the Semi-Orgasmic Lock-In Effect: In a rear-drive car, there's a division of labor -- the front tires basically steer the car, and the rear tires push the car down the road. In a FWD car, the front tires do all the work – both steering and applying the power to the road – while the rears are largely along for the ride. That, it turns out, is asking a lot of the front tires. Since the driving wheels tend to lose traction first, the front tires of front-drive cars invariably start slipping in a corner before the lightly loaded rear tires do -- a phenomenon known as "understeer." If you go too fast into a curve -- I mean really too fast -- the car will plow off the road front end first. In rear-drive cars, the rear wheels tend to lose traction first, and the rear of the car threatens to swing around and pass the front end -- "oversteer." If you go too fast into a corner in an oversteering car, the car will tend to spin and fly off the road rear end first.

What's the best way to fly off the road? Safety types prefer frontwards -- understeer. Why? To control an oversteering skid, where the rear wheels are heading for the weeds, you have to both slow down and counterintuitively turn the wheel in the opposite of the direction you're turning. In a front-drive car, with the front wheels slipping, you slow down and keep turning the way you'd been turning to get around the corner in the first place -- a more natural maneuver, since you're pointing the car in the direction you want to go. This is why, for safety reasons, even rear-drive cars sold to average consumers tend to have their springs and other suspension bits set up to make them understeer -- to make the front tires slip first, despite the car's innate oversteering tendency. Only by applying lots of power in a corner can you actually break the rear end of a bread-and-butter rear-drive car like the Mustang loose -- a maneuver favored by sports car freaks, but one you try at your own peril.

Big American manufacturers (all heavily invested in front drive) like to say that for 99 percent of drivers, driving at normal speeds, FWD's inherent understeer and better traction in the wet makes it preferable -- both safer and easier to drive quickly. It's only the 1 percent of speed freaks who enjoy breaking the rear end loose and then catching it with a bit of "reverse lock." Here's where I emphatically dissent.

It's pretty clear to me, after driving hundreds of different vehicles over several decades, that rear drive offers a big aesthetic advantage to ordinary drivers at ordinary speeds in ordinary conditions. Why? The lock-in effect I mentioned earlier. Suppose you go into a corner in a rear-drive car at a reasonable, safe, legal speed. Nothing's about to skid. But you can still feel the front end starting to plow wide a bit. What to do? Step on the gas! Don't stomp on it -- but add a bit of power, and a miraculous thing happens. The front end swings back in, the car tightens its line. Cornering traction seems to increase. And the car feels locked into a groove, balanced between the motive power from the rear and the turning power in the front.

You don't have to be a race driver to feel this. You can be a defensive driver and feel it. You can be driving a 1973 Ford Maverick with leaking shocks and you'll feel it. Accountants feel it on the way to the office and housewives feel it on the way to the Safeway. Even Ralph Nader probably feels it. It's a good part of what makes driving a car a sensual act. (What's happening, technically? None of the tires is at its limit of adhesion. But the added speed is making the front tires --which [since they are undriven] have plenty of surplus traction -- apply more force to the road surface to change direction. Meanwhile, the rear of the car is shifting outward, ever so slightly -- not a Bullitt-style power slide, but a subtle attitude adjustment that cancels the plowing effect. The power "helps you through the corner," as Zellner puts it.)

This doesn't happen in a front-drive car. The best an ordinary driver can hope for in a FWD car is that it "corners as if on rails" -- no slippage at all. No plowing -- but also no semi-orgasmic "lock in." More typically, if you hit the accelerator in a fast corner, things get mushy up front (as they did that evening near Jayne Mansfield's house). The lesson the FWD car seems to be teaching is: Try to go faster, and you're punished. Front-drive cars are Puritans! In a rear-drive car, you hit the accelerator and things get better! Rear-drive cars are hedonists. (This is assuming you don't hit the accelerator too hard.)

I'm not saying there aren't sophisticated techniques that allow FWD cars to do better. A recent issue of Grassroots Motorsports tested a humble FWD Acura RSX against a classy rear-drive BMW. The Acura actually turned laps a bit more quickly. How'd that happen? The Grassroots people realized that by stepping on the brake hard enough on entering a turn, the rear of the Acura could be made to swing wide, canceling out its inherent understeer. (This is the same effect you get by stepping on the gas in a rear-drive car.) But normal drivers aren't going to mash the brakes and go sliding through turns like a rally champion. Nor does braking to achieve "lock-in" seem as satisfying as accelerating to achieve lock in. I suppose I shouldn't knock it until I've tried it -- but I'm not going to try it! That's the point. Housewives heading to the Safeway aren't going to try it either. The joys of rear-drive are accessible to them -- it's the joys of FWD that are reserved for the skilled Grassroots Motorsport elite.

It's also now clear to me why Acura is in trouble (it only offers FWD sedans), why GM is busy working on a new "Tubular" rear-drive chassis, why the Infiniti G-35 and Lexus IS-300 (both rear drive) are so popular, and why the RWD Cadillac CTS and Lincoln LS are so refreshing to drive.

I'm not saying that any rear-wheel-drive car is better than any front-wheel-drive car, the way, say, any car with plain black tires looks better than any car with whitewalls. But it's close! Front-drive cars can be fun. Even bad s*x is fun. But why choose it?

[Phoenix999]

Wow this has sparked a debate

I have had FWD, RWD and AWD cars now and I can say they each have benefits.

I feel that a FWD car tends to be the slightly better daily drive when faced with variable road surface conditions especially where slippery roads are concerned. A RWD car clearly handles greater power in a better way as oversteer, in my opinion, somehow feels better and easier to control. The AWD car has far superior grip in all conditions and feels safer.... but.... give me a powerful RWD car any day

All cars can be controlled in all conditions if the driver knows what he/she is doing. We all have our preferences but Alberto I consider you are a fool.... look at the racing car world. Don't you think that all racing cars over a certain power output would be FWD if that was the way to go! I have as yet to see those red Italian F1 cars with a FWD configuration

Have I made sense? Somehow I doubt it as we all have our own opinions

[PaulT]

What a shame I hadn't read any of this thread before I lost the back end of my FWD Celica on track last weekend---embarrassing 180-degree spin!

From now on I'll know this can never happen

Paul.

[kimi]

ObsidianGT

welcome to the club

keep posting you know you want to

i have both FWD and RWD both can be fun its a personal preference ;)

funny how i never saw this topic when it was new back in 2007

kimi

[JappyBeast]

I remember it, thought it was a bit pointless!

[dawesy]

FWD rocks!!!!! *runs and hides*

nah FWD and big torque sucks, me going 4WD

[Leeky]

Yeah!? GT4 running gear or you finally moving away from the rolla dude?

[Karma Supra]

BWAHAHAHAHAHAHAH HAHAHAHAHAHA

HAAAAAAAAAAAAAAAAAAAAAA

I can't be ubikd with going into details all I'll say is:

Top fuel dragsters, designed for ultimate acceleration and speed are RWD. not FWD not 4WD.

F1 cars, designed for maximum handling and agility are RWD, not FWD, not 4WD

[1bloke1dog1mr2]

I remember it, thought it was a bit pointless!

Pretty much like most of the stuff Alberto was posting last year ;) !

[Fizz]

Amy - your spot on... i gave up biting after a couple of one way debates with him..

[dawesy]

nah 4WD running gear in the rolla!!

[ObsidianGT]

ObsidianGT

welcome to the club

keep posting you know you want to

i have both FWD and RWD both can be fun its a personal preference ;)

funny how i never saw this topic when it was new back in 2007

kimi

Kimi, will I get in trouble for bumping this?

Oh well, too late!

I got an email about this thread out of nowhere.

I don't have a Toyota anymore, so I'm not really interested in posting on TOC. But, I'm curious what the red car is in the top banner? It looks very nice.