Your pick for a 4WD car/suv (moving to, design)

[S6Sputnik]

Originally Posted by EscapeCalifornia

BTW, get good tires. All the fancy drive systems in the world don't mean a thing if your tires won't stick to the road. And 4WD/AWD doesn't improve cornering or stopping ability.

No doubt tires are #1 important, but your AWD statement I would have to say is wrong! and the worse the weather the wronger it is . Now all AWD systems are not created equaly, I base my experience on Audi's Quattro system.

[sunsprit]

Originally Posted by preppyglam

(snip)

Can anyone add anything about their experiences with AWD v. 4WD?

AWD systems, such as found in Subaru and Audi (two marques I've owned multiple models of, and drive now)... tend to be better performers on icy/slippery/hydroplaning ROAD conditions compared to 4x4 systems.

A lot of this results from the design basis ... AWD road suspensions are targeted to road driving, while most 4x4 suspensions are targeted to off-road driving, with longer suspension travel and substantially different suspension geometry than AWD cars.

Unless you are intending to go off-road with your vehicle, the better choice of systems for the black ice/slick conditions here is AWD vehicles. You will pay a price in fuel economy to have AWD compared to FWD only, but most of the AWD vehicles I've driven still get much better fuel economy than any 4x4 vehicle. The virtues of a 4x4 will show up in deep snow or mud or loose sand conditions with better ground clearance and suspension travel .... but those conditions are rarely what will be found driving on roads.

IMO, AWD results in far better handling, cornering, and control than any other system on the road. Even with moderate priced all-season tires, I've never had a problem getting around in Colorado winters ever since buying my first Audi 4000CS Quattro. Never needed chains, never gotten stuck, never been off the road with these ... and got close to 30 mpg composite driving. I'm a manufacturer's rep these days, and I travel the rocky mountain states for my sales calls, so I put a lot of miles on year 'round in all kinds of weather conditions. I've gotten similar results with my Subaru wagons, starting with a '95 Brighton wagon. The Subie's don't have the positive feel (for handling and braking) that the Audi's do, but they go just as competently in adverse driving conditions. OH ... my wife drives the '95 Subie now, and with 235,000 miles on it, still gets 32 mpg.

Of course, a driver can overcome the advantages of any vehicle in adverse circumstances. I've "rescued" neighbors up here in Wyoming who have gotten stuck with Toyota, Ford, Jeep, and GM SUV's with my Subaru OBW and needed a ride home so we could get the JD tractor out to pull their vehicles out of the barrow pit. One even got stuck (high centered) in a modest drift on a local county road, and I was able to drive up to their vehicle with my Subie, load up the 4 people, and drive away without any difficulty, much to their amazement ....

I've worked a lot on MB and BMW AWD cars in my shop a few years ago, and didn't find their systems to be better (if anything, far less durable) than those of the Subaru's. IMO, their expense hardly justifies the benefits. Friends with Volvo AWD vehicles have had mixed results ... the cars do well in adverse driving, but are also a bit "pricey" to keep on the road for the long haul.

[steveindenver]

AWD systems, such as found in Subaru and Audi (two marques I've owned multiple models of, and drive now)... tend to be better performers on icy/slippery/hydroplaning ROAD conditions compared to 4x4 systems.

The difference between AWD and 4WD is the formers lack of a low range. That is it. Thus while Subaru's are sometimes mistakenly referred to as 4WD they are in actual fact all AWD these days with the exception of the 70's Leon, the 80's Brat and an available 4WD Justy from the late 80's to early 90's.

As to how the power is sent to all wheels there are a multitude of different solutions.

Take your pick, not all are created equal nor do they perform equally under all circumstances. I won't bore anyone with a list of the various configurations, their benefits and drawbacks, but there is no inherent advantage to one under normal road conditions.

[EscapeCalifornia]

Originally Posted by S6Sputnik

No doubt tires are #1 important, but your AWD statement I would have to say is wrong! and the worse the weather the wronger it is . Now all AWD systems are not created equaly, I base my experience on Audi's Quattro system.

So you're saying that even when your foot is off the gas, having AWD increases the tire adhesion on the road that you need to corner or stop in slick conditions?

[sunsprit]

Originally Posted by steveindenver

The difference between AWD and 4WD is the formers lack of a low range. That is it. Thus while Subaru's are sometimes mistakenly referred to as 4WD they are in actual fact all AWD these days with the exception of the 70's Leon, the 80's Brat and an available 4WD Justy from the late 80's to early 90's.

As to how the power is sent to all wheels there are a multitude of different solutions.

Take your pick, not all are created equal nor do they perform equally under all circumstances. I won't bore anyone with a list of the various configurations, their benefits and drawbacks, but there is no inherent advantage to one under normal road conditions.

Here's where we're going to disagree on the AWD vs 4x4 in real world on the road driving in adverse conditions .... and it's more than the basis of a "low range" gearing. As you mention, there's lots of ways to distribute the power to all 4 wheels, and the differentials and inter-axle differentials play a big part in balancing the vehicle and it's performance on slick surfaces. And this effect holds true for cornering, too; the AWD system places the optimal amount of power onto the respective tires to enhance the cornering performance, even on slick roads.

I know from experience that driving my MB Jeep, my Dodge 2500 4x4, and numerous other 4x4's (including a forgettable Bronco and an International Scout), that when I hit icy surfaces ... it can be a "white knuckle" experience at cruise speeds on the highway. In my Audi's and Subaru, with AWD, it's almost a trivial experience, and many times ... you don't even notice that the road surface was as poor as it was until you see other vehicles near yours having difficulty maintaining control. That's because those AWD cars actively manage the power distribution and balance of the car much better.

While it's an advertising campaign, it's interesting to look at the Subaru "road test" videos where many other vehicles do not get up slick surfaces and the Subie does.

EscapeCa ... you miss the point that even when your foot is off the gas, there is a balance and distribution of the drag forces on the wheels that greatly affects how the vehicle will handle. While the drive system doesn't change the traction of any given tire, it does greatly affect how much load is placed upon each tire. It's why I can drive my 1982 MB300Dt in a lot of situations through the mountains on slick days and not need to use my brakes, because the motor drag is very pronounced on the rear wheels. Similarly, my Subie's balance the drag in a way that enhances the car's balance instead of just dragging the front end of the car or the back end of the car, so it takes better advantage of what traction is available.

[rkb0305]

Love my 2004 Acura MDX. Got it last fall for about $16K. We wanted a 3rd row for out of town visitors.

[steveindenver]

AWD system places the optimal amount of power onto the respective tires to enhance the cornering performance, even on slick roads.

This depends entirely on the system, of which there are a multitude and to what problem they are attempting to answer.

I used have a rear engine AWD vehicle that was for all intents and purposes a RWD vehicle. It *could* send up to 40 percent of the power to the front wheels, but in the snow it was more or less a rear wheel drive car with just about zero advantage being derived from sending power to all four wheels. Of course tires were a big factor here too. Put just about anything on a set of fresh Blizzaks and it will go in the snow.

Most AWD systems on the market tend to be adapted from either front or rear wheel drive layouts and more or less only send power to the other set of wheels when wheelspin is detected. This is less than ideal in a general sense and the sensation and effectiveness of such systems can vary depending on what type of center differential is used. Couple this with traction control systems (more about that in a second) and you have a very limited vehicle. Most all of the cute-utes come to mind here.

Subaru's symmetrical AWD system is different and in my experience ice racing a friends STi on good tires a total blast - and entirely different from say a Volvo V70R which has a pronounced desire to over steer in the snow. Then again, the STi uses a clutch style center differential with a mechanical limited slip device that is different from the rest of their lineup.

Another interesting thing to note -- with all of the bells and whistles applied to vehicles in the past dozen years or so, importantly among them the various means of traction control even a capable 4WD SUV can be hamstrung by the gadgetry. I managed to get the wife’s Land Rover stuck in an impossibly stupid manner at the edge of a road with just a slight rise in the snow. The stupid ****ing traction control system kept pulling power from the spinning wheels until you ended up with no movement. Fully disabling the system requires multiple steps -- and upon doing so the vehicle easily pulled itself the few inches it needed to before more traction was available.

The last snowstorm I witnessed a similar predicament taking place for a Lexus RX350 driver. As it turns out -- there is no way to fully disable the nannies in that car and he ended up needing to be pushed. Amazing.

Oh -- and with 4WD you can also quite easily manage to push enough snow long enough when it is really deep such that you end up ramping up onto it with no wheels touching the ground. Done that, sadly twice now.

[Brian_M]

Originally Posted by steveindenver

Oh -- and with 4WD you can also quite easily manage to push enough snow long enough when it is really deep such that you end up ramping up onto it with no wheels touching the ground. Done that, sadly twice now.

Lol... didn't learn the first time?

I've done it once (thought with my FWD car with 4" of ground clearance).

[maximusmgm]

Originally Posted by Brian_M

Lol... didn't learn the first time?

I've done it once (thought with my FWD car with 4" of ground clearance).

I've *almost* done that. I have 6" of clearance. I tried driving through what I estimate to be an 18" pile of snow. I got myself un-stuck (disabled the vdc in my subaru) and made it through though with snow flying all over the place. No digging required.

[EscapeCalifornia]

Do you carry a small shovel in the trunk just in case?