AWD does not mean 4WD.
E.g. http://www.autotrader.com/research/a...4wd-or-awd.jsp
"But AWD is not the same thing as 4WD - and it's arguably false advertising to lead people to believe otherwise. Each system works differently and offers different levels of capability."
And it's 95% / 5%, not 100% to the front.
However the logo on the back is 4x4 and not AWD - but that's probably just marketing.
False advertising my arse. Yes, there are different systems, and it's important to understand the difference, but their starting point that AWD^=4WD is nonsense. They've simply chosen to describe one system one way and everything else the other, and their 'definitions' are simply made up.
Which is a shame, as the rest of the article is essentially correct and informative, apart from trying to enforce this arbitrary difference in terminology which is by no means universal or consistent across the global industry.
So what I understood 4WD to be turned out to be not covered by AWD. An AWD will not have the grip characteristics of 4WD. If I drive my ÀWD as if it were a 4WD, I might have trouble.
Hence AWD is not identical, synonymous with 4WD.
E.g. http://www.motortrend.com/features/c...d/viewall.html
According to the Society of Automotive Engineers, an all-wheel-drive vehicle is one with an on-demand feature that occasionally or intermittently sends power to the non-primary powered wheels.
That article makes a clear distinction.
The technicalities may be of abstract interest, but frankly for most people they're irrelevant. The fact is, if you buy a car with 4WD, AWD, WMD or whatever - be aware that these thing have different meanings to different people, so if it matters to you, be aware.
I use nordic winter tyres and put 100kg of grit in the boot.
Normally all is ok but each car is different and depends what your wintet tyre size is compared to summer.
Can't get up the hill out of my house if there's snow (25% hill hairpin curve) unless there's lots of weight in the boot.
Auto seems to have no downtune winter mode or am I missing something? Manual into 2 or 3 and still no joy.
Discovery in the same make and model tyre......does not miss a heartbeat or spin or anything. Needs Low gearbox engaged in 30cm depth, though
But you're reading too much into the 'differences', and not enough into just how well they actually work.
In practice, a modern 4wd car, with electronically-controlled drive, stability, braking, systems, will be at least the equal of a traditional old-fashioned permanent 4wd vehicle.
Actually, I realise that this is the real definition, that makes sense. Permanent 4wd, which will work in a purely mechanical way for all sorts of conditions, or the modern e-4wd systems, which I think fall into your definition of 'AWD', which simply drive or brake wheels as appropriate without the need for much driver input or understanding.
All well and good, but the crucial point is this: a modern (e.g. haldex) variable 4wd system will get you out of trouble, or rather avoid getting into it, at least as well as the old-fashioned permanent mechanical systems your American links seem to suggest are better. Fact is, on snow-covered roads the former are actually much better. For driving through a swamp, across a desert or a muddy ploughed field, maybe not, but that's not what the OP was asking about.
Yes, on this we can agree.
The AWD/4WD argument really comes from the US. Their view point is you need a transfer box for it to be 4WD - IE the transfer for torque front/rear can be locked.
I don't see the relevance of that description for a road car in Switzerland. The vast majority of drivers are not buying a BMW 325xi and expect to go "green-roading" in it - in fact that would go the same for any of the BMW X, Porsche Cayenne, Audi Q brigade. All those do have a level of permenance to their torque split as they are derived from a RWD/in-line platform. (As mentioned before).
The US argument appears to derive from the more widely available HALDEX systems which are reactive 4wd systems - only shuffling torque when slip is detected.
In fact, I wish to redefine 4wd to:
Active 4wd - where the characteristics of torque split can be defined BEFORE slip
Reactive 4wd - where the characteristics of torque split are defined AFTER slip
How is that folks?
Oldie here!
In those days when front wheel drive was almost unheard of we all put heavy bags of sand in the boot in Autumn - which also was supposed to come in handy if you got stuck - and carried a fold-up military shovel to dig the car out if need be. We also had a brush and pan in the boot to clear up any glass in case we had an accident!! My first 5 years were with a Ford Cortina, a car that got us everywhere without complaining.
Only the Ms have a proper LSD. The new Alpina B3 has just been launched and I haven't checked whether that comes with a proper slippy diff. (It doesn't - not even as an option)