Why did all (most?) car makers change from BWD to FWD?

Factual Questions
21

I have an '87 Acura coupe with about 190K mi. on it. All but about 50 of those were put on it by me.

As to steering - I have NEVER had the front wheels break free (the left front is the drive wheel).

Anecdotes:

I routinely leave the folks who are on my butt behind when merging with high-speed traffic on interchanges - I drop back throttle upon entry to give the tail-gating morons in front of me time to figure out, one more time, that 2 objects (cars) cannot occupy the same space at the same time. This delay clears out the on-ramp for my use as an accelration lane - my FWD is accelerating while the morons behind me are standing on their brakes to take the curve. Sigh… people should not be allowed to operate high-speed vehicles (or reproduce, but that’s another story…).

I have driven in the following road conditions:

Clear, dry

Wet - including the first rain of the season - when the motor oil from the last 8 months rises to the surface. There’s a hint in there, folks.

snow (packed, fresh, and in various stages of being plowed/de-iced)

sheet/black ice

freezing rain - in February, 1991, I drove I-65 from Chicago to Florida. At the time, Indiana had freezing rain in the early (01:00-03:00) morning, and the shoulders were lined with long-haul semi’s (except the one in the center culvert just south of Gary - as there were half of dozen truckers on scene, I did not stop to assist). For the next 2 hours, it was just me and 2-3 State Troopers on the Interstate.

The only time I thought that maybe, just maybe, I’d have preferred your basic Detroit land yacht was on a washboard stretch of road in the high desert (no rain to smooth out the surface, and, as this was a road most of us would prefer others NOT to find, I thought it was a wonderful way to discourage dilettantes).

A few years ago I hosted a 17-yo neice who fancied herself a ‘wild child’ - I took her up to the giant sequoias - and demonstrated what scary driving was on the skinny, corkscrew back roads on the way back. The ‘wild child’ ended up in the fetal position. At no time was I not in control of the vehicle - not even close.

The only other car I’ve had which held the road as well was an old VW Bug - again, the weight of the engine/transaxle over the drive wheels made that the only thing moving when there was about 12-15" of fresh snow on the ground.

22

Without a limited slip your differential/transaxle will send power to whichever wheel resists the least (a basic flaw with them).

As far as the rest, its pretty simple. Pulling is self-righting and inheirently stable. Pushing is essentially the opposite. It requires constant, minute corrections and is inheirently unstable. There are other factors, but that’s the core of why FWD is generally better than RWD.

Think of a boat, or a shopping cart…

23
      • Car companies went to front-wheel-drive because it was cheaper. As they re-engineered the entire engine/drivetrain to make all the pieces smaller (as cars themselves got smaller and lighter) it became obvious at some point that they no longer needed to stretch the drivetrain out the length of the car. Better traction ain’t got nothing to do with it–that was just something they said after they had decided to do it anyway. The original reason that cars were rear-wheel-drive was that [in the past] mechanically it was easier to drive the rear wheels than the front, because the rear wheels did not need to be able to steer.
  • In moderate-to-high traction situations rear-wheel drive accellerates better than front-wheel-drive, and allows you to slide out the rear end with far better control. Nowadays the only cars that maintain rear-wheel-drive are those that the manufacturer doesn’t want to spend money to update, or that the manufacturer wants to provide “classic” sports-car handling–but for liability reasons, for the most part–US companies won’t admit to making racing cars anymore.
  • Also I would challenge anyone who thinks that front-wheel-drive is better than 4-wheel drive in very-low-traction driving (snow, mud, gravel). It just ain’t so. Borrow a truck that is switchable between 2 and 4WD, and go out and play in a mud puddle or the snow, and you will see for yourself.
    ~
24

Everything I’ve read and heard on the subject, as well as my own experience, is that the switch to front-wheel-drive is for reasons of cost, weight, and packaging efficiency. Rear-wheel-drive is still superior for handling and high performance.

And no one has mentioned weight shift, yet. Under acceleration, the weight of the car is borne more heavily on the rear wheels. (Think of a dragster during a run, it can shift the weight so far back that the front wheels barely touch the ground, or leave it completely.) Even without torque steer, there’s a limiting factor in how fast a FWD car can accelerate. As the weight shifts off of the front wheels, they will lose traction and start to spin. A RWD car (with similar engine and tires) can accelerate faster because it shifts the weight on to the wheels that are providing the acceleration.

25

And I agree with you. Does any one really think this?

If you have never had a wheel break free, what makes you think that your left front is the drive wheel?(which is incorrect in any case) - Just sayin…you should probably learn more about your car before you push it too hard.

26

FWD is definitely cheaper. This was probably the biggest reason for the automakers to start pushing for them. As was mentioned above, this probably has a lot to do with unit body construction. For a FWD vehicle, you build a body, then add the drive train to it. For a RWD vehicle, you start with a frame, which becomes an entire chassis – wheels, frame, drivetrain, everything but the body in gray. But you’re still building the body! This is a huge extra step in the manufacturing process. See the potential for savings here?

Torque steer is overcome-able. My previous GM vehicle 220hp FWD had very, very strong torque steer to the right when ragging on it from a full stop. My current Ford FWD 275hp FWD exhibits no noticable torque steer at all. I don’t know about the lesser Fords, though.

Front wheel drive on strong vehicles can be problematic, I suspect. I’ve already had to replace various front end suspension components on my car, and I have to assume it’s because it’s just not built to constantly accelerate from a dead stop with the gas pedal all the way to the floor, every single time (well, not every single time). On the other hand, I’m probably the only guy under 55 that owns one.

27

Isn’t that called “drifting”?

/learned how to drive from Grand Taurismo. :smiley:

28

After moving to Minnesota from Florida we had our first winter approaching.
We were loading some things into the trunk of my wifes 97’ Corolla.

Me- “Um, dear, why do you have two 40lb. bags of salt in your trunk?”

Wife- “I had the guy at the grocery store put them in there.”

Me- “Ummmm, why?”

Wife- “My dad used to do that in his car every winter in Chicago.”

Me- “Yes dear, however, I don’t think your father’s Ford was FWD.”

29

The 200hp FWD limit is a number you’ll hear very frequently. I believe it was said by some Alfa Romeo engineer. I’ll try to find the exact quote.

Note that Alfa Romeo makes several FWD cars with more than 250hp, but they are notorious for not allowing the driver to disable the electronic stability control.

30

It is overcome-able, but the car makers have to sacrifice steering precision and feeling and/or increase the steering wheel turns, which are both no-nos for sports cars.

The best example of this is the Civic (Euro) Type-R. In order to counteract the car’s strong tendency to torque-steer, they had to make the steering wheel very “light” and insensitive.

31

The GM was “sporty” (okay, it was a Bonneville). The Ford isn’t sporty, but it is a sleeper (okay, it’s a Continental). I haven’t thought a lot about steering precision – the Bonny and the Continental seem like they steer the same. Heck, they seem like they steer the same as anything else – I’m probably dead wrong, but driving is instinctual I guess and I just never notice but rather adapt. The Continental does, though, have adjustable steering resistance in three degrees, from that way-too-easy-to-turn mode to a very tight mode, kind of sporty. Suspension tunes itself in three degrees, too, so it does get kind of sporty.

Given that everything I’ve ever driven has been a “consumer” car or truck rather than a “performance” vehicle, I guess I just don’t know what I’m missing. To me Civic EX = Mustang = Tahoe = Bonny = Continental = Ranger. Of course, I mean turning the wheel – it’s obvious that there are a lot of things that make their overall performance very, very different.

32

Lots of good info and some bad here.
I think that Robot Arm nailed the reasons

Why FWD? Packaging as has been said. Not for the driveline, not for the hump, but for the people. I had this question come up in 1993 when we introduced the 850 (Volvo’s first FWD) here is what I answered then.
Why FWD? Simple, it’s all about space. Our current largest car is the 960 right?
Answer Right.
Does a 960 have more interior room than an 850?
Answer No
So what advantage is there to having a bigger outside if the inside is smaller?
Answer aaaaaaahh beats me.

Simply put, car makers are under pressure (CAFE standards) to make their cars have better gas mileage. Speaking in general terms, cars that are smaller, and weigh less get better gas mileage. So cars have been getting smaller for almost 30 years, but there is a limit of how small a passenger compartment a customer will accept. People want large interiors, but they also want good gas mileage. So to maximize the interior room for a given exterior dimension FWD is almost a must.

On the torque steer issue, torque steer occurs when the angle of the two axles is different causing the CV joint on one axle to be harder to turn than the other axle. This causes the car to pull to one side or the other. With early FWD this was a big problem. Nowadays the axles are equal length so the angles are exactly the same and torque steer is almost a thing of the past.* The only time I notice torque steer on the cars I drive is if I flog it hard when turning out of a driveway. The suspension loads unevenly, causing a very slight (as in hardly noticeable) amount of torque steer. This is much different than the early VW GTI when if you stepped on the gas the car would make a lane change.
As far as horsepower limits on FWD, thank OG nobody told our engineers that above 200 HP was impossible! Let’s see, our S80 is 268HP, my V70R is 300HP (It is AWD, but runs as FWD most of the time), S60T5 is 275HP or so. I built a 315HP race car out of a 850 Turbo and ran it the Silver State Classic car race. We crossed the radar trap at the finish line at 163 MPH. That car was also very streetable, no torque steer at all. The 315 was a number we got running the car on a chassis dyno, so engine HP was somewhat higher
As far as where the power goes, on any car FWD or RWD in absence of a locking diff, or some type of traction control power always goes to the wheel that has the least amount of traction. If both wheels have the same amount of traction, then both wheels will drive the car equally.

[quote]
4WD drive cars have 2 wheels on opposite corners doing that). [/quote This is not true. The one front and one rear wheel that have the least traction will be the ones that get the power. If you pulled off the road, where your left side tires were on dry pavement and your right side tires were in soft mud, and stepped on the gas, what would happen? Your right side tires would spin, and dig holes in the mud. This is why electronic traction controls are so popular.
As far as the hump goes, come on you can’t tell me the hump for a 3" diameter exhaust pipe is as large as the hump for a transmission bell housing that is 24" across! Or the body of the transmission that maybes measures 12" across. :confused:
*There is no technical reason for torque steer to be present in modern cars. The answer is out there, and it is not a difficult solution. However, if the bean counters won’t let the engineers have the money, then some cheap cars may still have unequal length axles and torque steer.

33

DantesTenth, if you’ve never had the wheels break loose on you, you’re not pushing the car to it’s limits. Most of the things you talked about in your examples have more to do with power to weight ratios and weight balancing than they do with FWD and RWD. I had a 1965 Ranchero that someone had shoehorned a 302 and an automatic transmission in, and I routinely blew the doors off of guys in hopped up “ricers” with manual tranny’s. On the initial launch they’d get maybe a car length ahead of me before I could catch up to them, after that, all they saw was my taillights. Pretty funny watching some slackjawed punk furiously row through the gears, desperately trying to catch up to me.

Weight balance can be tricky to get right in a car where the engine sits directly over the drive axle. Depending upon who you talk to, and what kind of cars they like to drive, you’ll get different answers as to what the ideal front to rear weight ratio is. The first Porsches had to have weight added to them on the front end, because the rear was too heavy and caused stability problems.

Rick, on my Chrysler, the tranny hump is buried well under the dash, and the drive tunnel starts roughly where the dash ends. Admittedly, I haven’t measured the drive tunnel in the Chrysler and then compared it to the measurements of the exhuast hump in my Pontiac, but visually, the tunnel in the Chrysler looks lower than the exhaust hump, though it is most definately wider. It might be an optical illusion, since the drive tunnel gradually slopes, whereas the exhaust hump is rectangular.

This statement

Pretty much nails all the problems in the automotive industry today, the bean counters are running everything, and when you add in places like GM where the engineers rarely get their hands dirty, you’ve got a recipe for disaster.

34

My 260 hp front wheel drive has a handy button on the dash to turn off the traction control and stability assist. There are many, many FWD cars with engines that produce in excess of 250 hp.

35

Ummm…

I have the original shop manual for this car, and have spent a few hours under the hood - replacing the starter, and adding fog and driving lights, filter changes, etc.

The shop manual shows, IIRC, the output shaft of whatever kind of gearbox/differential (it has never needed to be opened - the only major maintenance item is the timing belt, which requires the engine to be lifted from its mounts - I don’t do that) connecting to something real close to the LFW. I am not going down to check it, but that is my recollection. If I am remembering incorrectly, I apologize.

36

Obviously you can have as much power as you want on the front wheels. But the question is: Can you use that power during cornering? Floor the gas pedal inside a corner, and the car will start to understeer; the more powerful the car, the more it understeers.

37

GM actually has very good products these days. The real problem is when your engineers become unionized. They go home after 8 hours, don’t solve problems, and you end up with Chrysler-style quality!

38

But they don’t look all that pretty. (Which is mainly a design department problem, admittedly.)

39

Adding weight to the back of a FWD car is still sound advice because of the excessive weight differences between front and rear. If you have a FWD car it is easy to loose control in panic braking conditions. Go out on a rainy day and practice in a deserted parking lot. It’s an interesting ride when you loose control. Anti-lock brakes really help out a FWD car. The last time I tried to avoid a deer in a FWD car I found myself on the opposing shoulder facing the other way. Luckily no traffic involved. The next time it happened I kept it straight and lost a turning indicator lens.

It is always a bad idea to add the weight with a loose item like salt, which can shift and make things worse. Moving the battery to the trunk (over the axle line) is always a benefit. Adding weight behind the axle line is less beneficial because of the principles of rotating mass.

To answer the question, FWD cars eliminate the mass of a drive shaft and axle housing. The center hump remains intact because it give rigidity to the unibody but the transmission hump is reduced in the front. So there is a gain in foot room in a FWD car.

Although FWD cars have been around since at least the 30’s it is a little more difficult to transfer the power to a transaxle which requires a constant velocity joint to turn smoothly.

40

Remember the first commercially successful General Motors FWD car?

The Oldsmobile Toronado, introduced in 1966.

In 1967 my Dad bought one. It came standard with a 425 cubic inch (almost 7 litre) engine producing 385 horsepower.

I loved that car, drove it many times. My Dad was a big FWD fan after that, he also had a 1972 Toronado and then moved into Eldorados.

Oh yes, and in the 30s the Cord Motor Car company manufactured the Cord L29, a front wheel drive vehicle. They later introduced the 810 and 812, of which my dream car is a 1937 Cord 812 Beverly Sedan, like the one pictured here. The 812 had a 288 cubic inch (4.7 litre) Lycoming V-8 engine with a Schwitzer-Cummins supercharger producing 195 brake horsepower. Not bad for 1937. It would push this 3800 lb. behemoth vehicle to an unheard of top speed of 111 MPH (179 kmH).

Tuckerfan may like his Tuckers, but give me a Cord 812 any day of the week! No offense intended, Tuckerfan!