The bit I never fully understood was Audi mounting engines longtidudinally but remaining FWD or 4WD. So you got the packaging issues from the RWD cars but not the benefits. The Passat B5 (sharing the Audi platform) also had this as an issue....
I do know it meant they could fit a 4.2 V8 in the front... Difficult in most front drive platforms!
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Saab 99 was FWD with longitudinal engine and had pretty decent packaging especially the Combi .
alfalfa
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As did the Saab 96. One of the many things that interested me about ours was that the V4 engine was mounted ahead of the front wheels. Maybe this accounted for it's incredible grip in snow - when my wife was running this car, I had an Audi 100, and the Saab was a much better bet in snow (we lived in the Pennines at the time).
As for the superior handling of RWD - shame for the rest of the competitors that nobody told Erik Carlsson and Paddy Hopkirk, whose lower powered Saabs and Minis saw off all the RWD competition.
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There's an interesting writeup on the Pug 3008 on this site.
One version has electric motors in the back and an IC* engine driving the front
To me, this is the wrong way round. The electric motors should drive the front wheels - and recover energy through the brakes, and the main engine should drive the rear wheels.
Though, I have to add that all (?) motorcycles are currently RWD :-)
* = infernal combustion
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Isn't there a category error here?
BMW and Mercedes are pretty mainstream.
As are Ford and Vauxhall.
If you want RWD you can buy it.
If you want cheap, you can buy it - but it'll be FWD.
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Or very cheap Smart: RWD only. With certain drawbacks, but the rwd BMWs have drawbacks such as being abandoned in the snow on a slight incline.....
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Don't all RWD cars get abandoned in the snow though? Are you saying that BMW's are more prone to suffering this? If so, please tell me (genuine question) - I have a vested interest in knowing.
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There was a thread about this , I think last winter. Lots of opinion as I recall.
Anyway, it's true enough that FWD is easier to get started from rest on a slippery surface than RWD but in my humble opinion and experience RWD is easier to control once moving when grip is compromised. Trouble is there are now a majority of drivers who have never experienced RWD cars or how to drive them in low grip conditions. They find themselves in a Beemer or a Merc in an inch of snow and don't really understand how to get the best out of them. Not their fault of course. Just the way it is now. Years back when RWD was more common it still snowed and people managed surprisingly well. Different technique that's all.
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Don't all RWD cars get abandoned in the snow though?
Not at all, most of us manage perfectly well.
Bit of weight in the boot works wonders and decent tyres help.
FWD isn't all it's cracked up to be, the advantage most of them have is that the car is usually heavier over the driven wheels
Why BMW's with their almost 50/50 weight split get abandoned so often (allegedly) i can only put down to poor driving.
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BMW no more than any others, SFAIK - just a brand plucked out of the air:) As others have pointed out, its an issue that can be overcome, with correct tyres and technique. But RWD cars do seem to be difficult for some to master in adversity.
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The only reason RWD cars get abandoned in the snow is because drivers don't know how to handle them. Watch your wheel revolutions, your speed and your engine revs and it won't be a problem.
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They don't hold a gun to your head to pay them vast sums, we're quite free to buy something thats pleasant to drive instead.
The problem being that 95% of car buyers wouldn't have a clue whats going on underneath anyway, and arn't in the slightest bit interested.
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Though I have to add that all (?) motorcycles are currently RWD :-)
As are all HGV's. I see far more FWD cars stuck over any given winter than I do lorries; I suspect because most car drivers have absolutely no idea of how to drive in snow.
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it's the sporty tyres that are the problem in the snow. first primera i had was on sporty dunlops and useless in snow, changed to goodyear hydragrips? and it was a very good car in the snow. jag.
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Agree
People are also obsessed with having fat, low profile tyres and our absurd minimum tread depth of 1.6mm doesn't help either. AND they are cocooned in warm cosy cars with a T shirt on and they are too stupid to compensate for the winter weather AND they are in too much of a hurry because "life is sooo hectic these days" when all they really are trying to do is to get home to a microwave meal and watch Eastenders, go on Facebook etc. Even though life is sooo busy.
I'll stop now sorry.
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One of the reasons why B5 VW Passats and Audis mounted the engine north/south and used a transaxle was to keep the driveshafts of equal length thus eliminating torque steer.
They don't have the same packaging issues as rwd as stated above.
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One of the reasons why B5 VW Passats and Audis mounted the engine north/south...... They don't have the same packaging issues as rwd as stated above.
No, but they're very nose heavy instead. Note that the latest Passat now has a "proper" FWD transverse mounting...
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>>No, , but they're very nose heavy instead. Note that the latest Passat now has a "proper" FWD transverse mounting...
How can they be nose heavy? You still have an engine and gearbox up front whatever the orientation.
There is actually more of the lump behind the front axle line than in a transverse layout.
I have a B5 Pasat and a new model Jetta and I would say the weight distribution is better on the Pasat.
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How can they be nose heavy? You still have an engine and gearbox up front whatever the orientation.
Because, in order to have the longitudinal set-up, not ruin the interior space and run FWD, they pitch the engines up quite far forward under the bonnet, resulting in more weight in front of the axle than other RWD or FWD set-ups. This is well known Audi quirk that's much commented on by many motor journos over the years... Try googling for "Audi" and "nose heavy"...
Still, if you find it OK, then that's cool - just IMHO it's not the ideal set-up.
Edited by TheOilBurner on 01/08/2009 at 18:34
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As an owner of one of these afflicted "Audis" (old Skoda Superb = old Passat in drag), my observation is that the design does not suffer so much from front end weight as polar moment of inertia.
Assuming that for a given car size/power unit rating, the engine and transmission assemblies are likely to be of similar weight whether mounted transversely or longitudinally, the operative factor becomes the location of the centre of mass of the power unit, relative to the front axle.
The Passat/Skoda handles like a boat because there is too much weight ahead of the axle. Even in the long wheelbase encarnation which is the Skoda, the dynamic performance is poor when conpared with my old (proper) SAAB. The difference, of course, is that SAAB adopted a very expensive transmission arrangement featuring a primary drive which enabled all of the transmission to be positioned under the engine.
Luckily, for my job (towcar) having the engine hanging yards ahead of the front axle gives good traction when the back end is loaded. VAG have, of course now abandoned this layout in this size sector of vehicle. The lack of torque steer on the NS layout VAG vehicles is due to the front swivel geometry - but with a total of 8 balljoints in the front suspension (+ 4 more on the steering rack) the execution is a real liability...
659.
Edited by 659FBE on 09/08/2009 at 17:33
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People are also obsessed with having fat low profile tyres and our absurd minimum tread depth of 1.6mm doesn't help either.
Why absurd? I never had a problem when the minimum tread depth was 1mm.
There are "drivers" who think that because they have 7mm tread depth they can drive at 70mph in a monsoon
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With mechanical drive systems it looks like FWD is the best all-round compromise for small and medium cars and will remain so. If we see future hybrids adopting hub-mounted individual electric wheel motors, where there is no mechanical driveline, then FWD would lose its packaging advantage and it would be relatively easy for manufacturers to offer a choice of FWD, RWD or 4WD on the same model.
Edited by Sofa Spud on 01/08/2009 at 14:06
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Absurd because 1.6mm gives next to no grip or water shedding ability in poor weather conditions.
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FWD is indeed all it's cracked up to be, and with ABS it's good fun on small country roads in the snow when there's no traffic. These cars are just fantastic. The whole point of manufacturing RWD is that you can delude the gullible that they are such proficient drivers that they must buy more expensive vehicles in which to zoom around (I could save minutes on that journey, knock that hospital down..)and get back in time for EastEnders (a popular programme on the television, I believe). There is at least one manufacturer who caters for this type of driver.
Hydraulic power steering works for 15 years with absolutely no problem and no maintenance in my experience, and electric power steering seems just as good despite the comments of pundits. Lets hear it for FWD- RWD may for all I know be better at 100mph but who cares?
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I'm the OP and this wasn't a topic to discuss if RWD was better than FWD, just a question if it was commercially viable for ONE mainstream (rather than premium badges) manufacturer to sell a RWD mondeo sized car.
My preference is RWD but I fully accept that FWD is more suitable, in more situations for the masses.
I have had 3 series/c classes, etc and whilst they are great cars, they are not full size family cars like the Mondea/Insignia are. The 5 series/E class cars have the size but also large price tickets to go with them. That's why I questioned a mainstream manufacturer making a family sized car at mainstream prices.
I guess the debate has proved that some people on this site would prefer a RWD car however as I stated on my orginal post, we may be enthusiats and not typical of the motoring masses. My wife couldn't care less if a car is FWD/RWD/AWD as long as it has PAS, an auto box and is quite comfy.
Take care all
Edited by a900ss on 09/08/2009 at 18:47
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How much extra would people pay for rear wheel drive? How much would the expert drivers of the backroom pay? How much would an ordinary member of the public be prepared to pay?
One thing is for sure - it costs a significant amount extra to provide rear wheel drive, it certainly isn't a no-cost option.
>>How much would an ordinary member of the public be prepared to pay?
For, it's only if ordinary members of the public would pay that any mainstream manufacturer would tool up to produce such a car.
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One thing is for sure - it costs a significant amount extra to provide rear wheel drive
So that's why Triumph, when developing the Dolomite 1850HL/Sprint, changed from FWD to RWD (with fully independent suspension all round, I might add) on the grounds of cost? Personally I think that the RWD is more expensive thing is a load of slurry designed to stop ordinary motorists having fun and to drive those who insist on RWD to more expensive prestige brands.
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Back to the original question then...MG Rover went to all the trouble of converting the 75/ZT into RWD, and that wasn't exactly a run-away success, although the big underpowered yank V8 might have had something to do with it.
The economics just aren't there for mainstream cars anymore. I'd love to know how many BMW/Merc/Lexus owners even realise that their cars are RWD.
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I enjoyed all my BMWs -mainly because of the joy of RWD - I preferred it then and having driven recent fwd cars (I include the CRV in this) find that they are still not quite what I like in a car. Been out in a newish (08) A3 Quattro today - brilliant car if rather soulless in the handling dept - but felt totally safe in all scenarios encountered on the 120 mile trip. (Mixed As and B roads)
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Well put! There is a "joy of RWD" for those who like the characteristics of that form or drive, just as there is a "joy of FWD" for others. Neither group of people are wrong.
I'm not surprised that you felt safe in an A3 Quattro. In poor conditions AWD is a more reassuring prospect than either FWD or RWD.
I am seriously considering AWD for the next car that I get. Closer to the time I'll ask the BR for advice.
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The economics just aren't there for mainstream cars anymore. I'd love to know how many BMW/Merc/Lexus owners even realise that their cars are RWD.
I have a Lexus IS and live in Cumbria (any of you BR's drove on Cumbria's A and B roads) and I certainly know i'ts RWD Brillllllllllllll
DJ
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I remember the big deal when the Escort shifted from rear to front wheel drive - around 1980 I think. My brother got one and the lack of any sort of transmission tunnel certainly freed up rear foot space in the middle.
And then when the Mondeo replaced the Sierra, it was probably deemed to be better handling than the Sierra (4x4 versions like the Sierra Cosworth and Escort Cosworth derived model excluded).
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Well - I'm going to risk it in an "Emperor wearing no clothes moment"; I have driven many Focuses over the years, both in petrol, diesel Mk1 and 2 guises. Whilst the handling is undoubtedly good (possibly excellent) compared to other cars in its' and, indeed, other classes to me it still feels "dead" around the middle of the steering range - as I say I have driven dozens of them and none of them feel any different - maybe terminally flawed in its FWD way ???
MX5 (case for the defence) driven two examples an 02 1.8 litre which was RWD joy in all respects and latterly a brand new 2.0 demo. Absolute peach of car in every way, especially in its perfect (for me) RWD set up.
The owner of the Quattro has part ex'd it for a brand new 2.0 Sportech MX5 due on 1st September - we both wait with bated breath !
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One thing I find ironic - when the original FWD Escort came out a lot was made of the space going to FWD. Which was true. But a lot of platform sharing today means most FWD cars have some of the draw backs of the RWD cars - a transmission tunnel.
VAG can be FWD or 4WD so need the tunnel. My Mazda6 was available as the MPS which was 4WD. The Rover 75 was engineered to be either FWD or RWD (the latter only available towards the end).
The Passat B5 1 was compromised in terms of space due to the orientation of the engine. Most were FWD, as were the Audis it shared components with but they had longitudinal engines... but not RWD. Okay again 4WD was on some models (and Audi A4 and larger still have longitudinal engines).
1 Of course the longitudinal engine meant the compact 4.0l W8 fitted in the Passat B5 but it won't fit in the current Passat which shares a platform with the Golf etc.
Edited by rtj70 on 10/08/2009 at 17:45
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My own (and no doubt flawed view) is that FWD is an accountant's rather than an engineering led solution. BMW 330d and 330i are amongst the finest handling saloon cars, not least due to where the driven wheels are. Mind you they are crap in the snow !
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Mind you they are crap in the snow !
Not with the correct winter tyres! In Europe they'd be fine. It's us with mostly not too cold or icy winters that have problems.
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is that FWD is an accountant's rather than an engineering led solution.
What exactly do you mean by that PU?
The accountants versus engineer's argument is one that is often used in cases like this, but, I really do not understand it.
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Production line costs - drop engine/transmission into the front of a car vs engine/transmission/ prop shaft and rear axle thingy. Happy to be educated if there isn't a cost difference.
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No, there's definitely a cost difference. And it's quite significant.
The point is that manufacturers have clearly taken the view that most people won't pay the extra - adding rear wheel drive will not add the same profit that adding, say, a leather covering to the gearlever might.
It's no surprise that RWD has become entrenched at the upper end of the market - where it's extra cost becomes a small proportion of the overall cost of the vehicle, and in the part of the market where the buyer is more likely than the buyer of a small hatchback to be concerned about which wheels are driving the car.
So, rather than saying FWD is a triumph of accountancy over engineering, I would argue that it's actually a better fitting of a car's specification to the needs of the people who are going to buy it. In other words, it's actually a triumph of engineering.
For me, the engineering versus accountancy battle is much more likely to be seen in the detail (the bits where most buyers are quite blind) - how are the switch contacts plated? Are the electrical connections well weatherproofed? Are the hose clips plated to prevent corrosion? Are the pipe runs well supported and routed? Is the timing chain single row or double? Are the ignition and injection parts any good? (preferably Bosch).
From a purist's point of view, the drive should be continuously apportioned to whichever of the wheels can best cope with it - an intelligent all wheel drive. So, in those terms RWD is a compromise.
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You should have been a politician ! :-)
Remember I was married to an accountant for 25 years and can come within a galaxy of knowing how they think !
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Re-reading your post and applying it to the Quattro I drove today I have to agree with you. Lovely drive - if rather sanitized in delivery. The car I had had a rather "rorty" 170 PD engine, linked to the new VAG Common Rail I would say it could be almost perfect !
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From a purist's point of view the drive should be continuously apportioned to whichever of the wheels can best cope with it - an intelligent all wheel drive. So in those terms RWD is a compromise.
IMO FWD is a bigger compromise, as you are ask the same pair of wheels to power AND steer.
That in a nutshell I believe, is why us RWD fans prefer RWD.
IMO, I honestly believe there is a better feel when the chassis is on its limit, by that I mean you can feel/sense then the grip between tyre and tarmac is at the point of letting go.
with RWD, under power you can feel that the drive wheels are loosing grip, and in cornering you can feel the grip through the front wheels - and then adjust the inputs as necessary.
With FWD, you are trying to read both through the same wheels, which muddies the water, so to speak.
Also, on a technical level, by combining two forces (acceleration/deacceleration and steering ) the grip is more likely to be lost in a big way, and without the warning you get with RWD.
Of course none of the matters much if the cars are driven in a 'normal' way! ;-)
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Best FWD drives for me were in order of Joy - Ford Puma 1.7 and close behind our Golf GTi ! Endless list of RWD cars including ancient Morris 1000s.
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IMO I honestly believe there is a better feel when the chassis is on its limit by that I mean you can feel/sense...
I think that used to be a valid argument, but with cars increasingly using electric power steering, there's practically no feel in the steering whether it's FWD or RWD!
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I think that used to be a valid argument but with cars increasingly using electric power steering there's practically no feel in the steering whether it's FWD or RWD!
Agreed.... another reason I strongly dislike all the electronics on modern cars!
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>>as you are ask the same pair of wheels to power AND steer.
As per a recent thread - just because the front wheels turn relative to the car during steering does not, of itself, mean that they bear any extra load.
For most people, who never go anywhere near the limits, FWD or RWD is completely irrelevant, and it's much easier to convince them to pay a bit extra for posher seats and a better stereo than it would be to get them to pay the extra for RWD. I'm not overwhelmed by the number of (abhorrent) BMW 1 Series that I see in comparison with the number of (equally disgusting) MINIs.
I agree about the subtelty of feel, but, for most drivers it's an irrelevance.
Like most photographers will produce adequate photos with a standard camera with automatic settings but would fail to get anything even focussed from a top of the range professional SLR - yes, the pro will get top results from the SLR, but, that doesn't make it the right camera for everyone.
To reply to PUs almost below the belt politician jibe!, imagine that you are chairing a concept design meeting for a mainstream manufacturer considering introducing a new Focus sized car - would you even allow the meeting to spend any time discussing rear wheel drive?
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>>as you are ask the same pair of wheels to power AND steer. As per a recent thread - just because the front wheels turn relative to the car during steering does not of itself mean that they bear any extra load.
SNIPQUOTE!!!!
I agree with all of that, NC.
The fact is that for most driveing done by most peopel there is damn all difference.
In fact most people seem to confuse handling, road holding and steering, all totaly different things but all things which do interact to some extent.
Roadholding is the absolute measure of how much grip a car has, in other words how hast it can take a corner of a given radius. It is something which cvan be measured absolutly.
Handling is the desription of how a car behaves as it approaches the limit of roadholding. If it tends to try to go in a straight line whe say that it understeers and if the back end tries to pass the front end we say that it overseers. Oversteer is not to be confused with a power slide in a RWD car.
If both ends of a car run out of grip together we say that it is neutral. If the car is designed to be neutral it will in fact be difficult to drive near the limit as the driver will not know in advance which end is going to give way first.
Handling I would say is subjective, it can be described but not measured.
Steering I would describe as the combination of feel for what the front wheels are doing and the gear ration between the steering wheel and the front wheels. If a car understeers the steering should have good feel while a car which oversteers can get away with steering which is just quick.
Weight distribution and polar moment of inertia are two differnt things. The weight distribution is just that, the ratio of the weight on front and back wheels.
For acceleration we want most of the weight, better still all of it, on the driven wheels. As the car accelerates ther is weight transfer to the rear so in the case of acceleration, I mean hard acceleration, not a trip to the supermarket, RWD is the way to go. The extreme case of course is a dragster or a quick bike doing a wheelie.
In the case of brakeing we have weight transfer to the fron of the car. The wheels which are driven are of course irrelevant but the weight distribution does matter. If we want to have the front and rear wheels do an equal part of the work we want to start off with more weight on the back than on the front. Although which wheesl are driven is irrelevant from in brakeing case the fact that we want a rear weight bias to get the ultimate brakeing performance means that RWD wins the day.
The polar moment of inertia we can describe as a measure of how close the masses of the car are to the center of graivity of the car. BMWs clain to have about a 50/50 weight distribution but I would imagine have a fairly high polar moment of inertia. Low polar moment of inertai means that a car can react more quickly but catch out the unaware more quickly.
In the case of steering the FWD does have a problem in that most of the weight is going to be on the fron wheels and there is probably some torque steer so power steering is going to be pretty nuch essential, at least if you want to be able to sell any number of them. The problem is that the pwer steering tends to mask the steering feel while the FWD car will tend to understeer and woud idealy give good steering feedback.
From the cost point, back in the days when RWD was an engine at the front driveing an axle hung on the back with cart springs FWD would have been more expensive. These days when every car has some form of half decent rear suspension that would not be the case and also the FWD engine/gearbox/final drive package can be easly used across arange of cars so I would think that it would win on cost for a volume manufacturer.
Another thing about the FWD/RWD discussion is that these days most drivers have learned to drive on FWD and the transition to RWD can be expensive! It is amazing how many cars with rear damage I see at the local Lotus specelist.
Haveing said all that I would say that for a car which is to be enjoyed RWD is the way to go but to make money selling a car used for transport FWD makes more sense.
Edited by Dynamic Dave on 18/08/2009 at 15:13
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