FWD RWD AWD

[C M Smith <cmsmith@domain.elided>]

For those who will not buy one or other of the above because it "wouldn't 
drive right" please remember that FWD actually has a theoretical 
superiority to RWD in generating cornering force. This results from the 
intuitively correct suspicion that turning the drive wheels in the 
direction of the desired direction actually produces a cornering force 
derived from traction and not from slip angle.

AWD may be superior for some applications but carries a substantial weight 
penalty (and cost). Also, the dead feel on the steering can be annoying to 
some (er... some consider dead steering to be a virtue on FWD, as that 
means no torque steer, I beg to differ but there you are).

RWD actually has little to recommend it for a road car. For a racing car it 
is generally accepted to be superior to other layouts, but it isn't 
actually. All successful rally cars are AWD for the simple reason that with 
enough power the weight penalty doesn't matter, and the handling/traction 
is unbeatable. So why does the myth of the superiority of RWD persist? It's 
more fun! But apart from that, a well sorted FWD will outperform a RWD car 
in almost all road situations. Racing and slalom etc show a superiority for 
RWD that is simply not borne out by the physics of the thing. It's purely a 
driving thing.

I've driven FWD for so long now, RWD just feels weird. It's just so bad in 
slippery weather I wonder why anyone puts up with it.  I drive 
hard,  winter spring summer and fall, and just can't be bothered to adapt 
my driving style to the season (wise, as in Calgary the seasonal weather 
doesn't match the actual seasons!). With FWD, you just drive. Sure, I've 
lost, even spun, FWD cars (a neat trick I can tell you, only on snowy roads 
though), but generally you can recover a FWD easily (unless it starts 
spinning then you're just a passenger).

Now, AWD is very entertaining, but even Audi and Subaru, probably the best 
exponents of the genre at the moment, haven't really dealt with the dead 
steering feel. Plus it is very difficult to position the car using the 
throttle, something very easy to arrange with either FWD or RWD. Also, the 
precise split of torque front to rear is very important and different 
depending on the situation (now don't start claiming Porsche has solved 
these problems, they haven't, though I admit I have not driven an AWD 
Porsche, more's the pity). And on a street car developing less than say 230 
hp the weight penalty is just too much. Once the power goes much above 230 
hp then FWD runs into pure traction problems which do not affect RWD or AWD.

  In slippery weather AWD gives one an entirely unjustified feeling of 
security which can really get the unwary deep into the doodoo with no way 
out. Last time I checked even Chrysler equipped their cars with four wheel 
braking (though it can be hard to tell that the rears are working until 
they lock up and spin the Van) (aren't all Chryslers vans (or trucks) under 
the skin?) so AWD cars do not have any inherent superiority in slippery 
weather that I can make out anyway (for the street).

I would never have a RWD car as my daily driver in winter, they just are so 
primitive (especially the BMW and Mercedes which are just a joke when the 
going gets tough, hmmm neither marque even attempts the World Rally 
Championship). But, I concede that it is a matter of taste and expected 
driving conditions. Just a word to those died in the wool (woops, froidian 
slip?) (oh keep those puns and letters coming) RWD aficionados, try living 
with a really good FWD car before you make your final decision, a 164 would 
be an excellent first choice.

Michael Smith
Calgary, Alberta
Canada
91 Alfa 164L, White, original owner

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End of alfa-digest V7 #1457
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