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AWD vs 4WD? - Page 2

post #31 of 156
Quote:
Originally Posted by Finndog View Post
AWD is far superior to 4wd.
That would depend on application and driving abilities.

I've got a pretty simplistic approach to this:
If it has a locking differential with 4-Hi and 4-Lo applying power equally and doesn't kick itself out based on speed, it a 4x4 and shouldn't be driven on dry roads at higher speeds as the differential is putting power to both sides equally and the driver and passenger side needs to be able to turn at different speeds.
If it has an electronic system applying power to each wheel individually as needed, it's AWD and is the way to go for a ski vehicle to be used on highways and not for serious off road driving.
Very few SUVs are actual 4x4's, they're variations of AWD/full time 4WD. The smaller ones tend to have systems that only engage at lower speeds to assist with initial acceleration, which is what most people "need" for getting the city.

My humble opinion - Most people would be better off taking things in steps with #1 being take a driving course that teaches you how to truely handle a vehicle. Then buy the technology to make things easier.
post #32 of 156
My $0.02, if you routinely drive off-road (such as jeep trails), or deep snow and mud, you probably need a 4WD Low transfer range in addition 4WD High.

If you're talking about driving to go skiing and need traction for that, get AWD.
post #33 of 156
Quote:
Originally Posted by therusty View Post
AWD should be sufficient and more practical for normal winter driving. But if you've got the insanity to try driving when the snow is above your axles....
I actually like the "insanity" of snow over the axles - most pleasurable time to drive. The roads are infinitely less crowded (sometimes barren) and the friction from fresh snow is just about as good as it gets - more packed (but not glazed hard) is better. Nice snow shots and clouds of snow flying around the vehicle - only one thing better... and I think we all know what that is!

It gets bad after the salt/sand plows leave 2-3+" of icy slush and the public begins to venture forth. The absolute worst is after the scraping leaves a thin film of water that turns to black ice and everyone thinks it’s dry pavement. Only then is salt a good thing.

AWD for me… 4WD Lo/lock with high ground clearance is great for tuggin' it - especially to secret fishing holes, but unless you've got property back in the woods on a "real" mountain, it's not required for lift-served skiing.
post #34 of 156
From 1999-2005, I drove a '93 Toyota Landcruiser with full-time 4WD, locking diffs and low range. The thing was practically unstoppable, at least until the price at the pump skyrocketed. Last season, I bought a VW Passat 4-Motion, which is equivalent to an Audi Quattro (AWD).

With snow tires on the Passat, the only difference I've noticed between the two vehicles is the ground clearance - and only in springtime (i.e., mud season). The road my house in VT is on can often have mud 6" deep, and where the Landcruiser would simply plow ahead unfazed, the Passat was bottoming out and wandering all over the road. Of course, driving through 6" of mud is not exactly normal.

That's my East Coast opinion.
post #35 of 156
Quote:
Originally Posted by JeffW View Post
...a 4x4 and shouldn't be driven on dry roads at higher speeds as the differential is putting power to both sides equally and the driver and passenger side needs to be able to turn at different speeds...
really, you shouldn't drive a 4X4 on dry pavement, period.

In the Army, we were shown film on how you could literally flip a jeep by doing a turn in 4WD mode on dry pavement (admittedly, this was many years ago, before electronic drive systems were even invented).

Don't put a 4WD in 4WD until you need it.

My plug would be for the Chevy Blazer. I drove one as a company vehicle a coupla years ago. My winter day would typically start with getting out of the driveway (if we had fresh snow, I could have as much as 2 - 3 feet of freshies in the driveway - I lived above 8,000 feet in the San Juans) in 4WD low, getting through the 3 foot berm from the snowplow at the end of the driveway, stopping, shifting to 4WD High, driving down valley about 20 miles before running out of the snow belt, shift into 2WD on the fly - that vehicle allowed shifting below 50 mph.

Often I would get called for service calls (I supported computer systems on gas drilling wells) that involved 25 miles of pavement, 25 miles of gravel/dirt roads in 4WD high, 10 miles of bottomless mud in 4WD low, using all terrain tires. I never found it necessary to put mud tires on the vehicle, and never had to chain up to make it through the mud.

I would gladly buy one for myself in a second, if I could afford the 18 mpg highway.
post #36 of 156
Quote:
Originally Posted by JeffW View Post
That would depend on application and driving abilities.
I would say much more application than driving ablilty.
post #37 of 156
I'd seriously consider the Toyota Matrix as an inexpensive AWD snow car. They get great gas mileage and actually have good legroom in the rear. I like the base model over the XR, mainly because there's less body cladding to drag around. For a sub $20K vehicle, you can't really do much better. Add a rooftop box and you're done.
post #38 of 156
Quote:
Originally Posted by Alaska Mike View Post
I'd seriously consider the Toyota Matrix as an inexpensive AWD snow car. They get great gas mileage and actually have good legroom in the rear. I like the base model over the XR, mainly because there's less body cladding to drag around. For a sub $20K vehicle, you can't really do much better. Add a rooftop box and you're done.
You can only get the AWD in an automatic. For under 20K the Subie Impreza or a base Forester. (Being Subie biased and all ). Plus you get a superior AWD system.
post #39 of 156
Quote:
Originally Posted by trekchick View Post
Its not you your list and I refrained from adding my input because I don't want to confuse you further, but......
I have had good luck with my Jeep with quadratrac.
Second that! Our Jeep was the ONLY car moving down I-70 during the massive spring storm in CO a few years ago and the LAST one through before the whole thing shut down. That included a bunch of Subarus on the side of the road because of clearance and a bouquet of Lexus and Toyotas and others. It has AWD available and you can also engage 4WD lo on demand. We had to use it a few times that day weaving around stuck cars and semis in the real deep stuff. I know you don't want it for off road, but it is a true off road vehicle when needed. we have driven some outrageous tracks in it with no problem. A wonderful, wonderful car.

If you want gas savings, you could consider the liberty deisel.
post #40 of 156

Can o' worms

Quote:
Originally Posted by icanseeformiles(andmiles) View Post
My $0.02, if you routinely drive off-road (such as jeep trails), or deep snow and mud, you probably need a 4WD Low transfer range in addition 4WD High.

If you're talking about driving to go skiing and need traction for that, get AWD.
This is an excellent summary, and it may be all you really want to know.

If you want to know more, well, we could go on and on. There are many different variations of both "AWD" and "4WD," and the meaning associated with each has been corrupted by people in marketing and journalism who don't really understand the technologies and subtle (and not so subtle) differences involved.

Despite what someone in this thread said, all motor vehicles intended for even occasional on-road use allow some kind of speed differential between the wheels on the inside of the turn and those on the outside of the turn, both at the front and at the rear. Even military Jeeps have front and rear differentials. "AWD" generally also allows a speed differential between the front drivetrain and the rear drivetrain, which is necessary on high-friction surfaces because, in a turn, the rear wheels will describe smaller arcs than the front wheels. The term "4WD" is generally associated with systems that lock the front and rear drivetrains together so that both must turn at the same speed. This mode can be very unstable at high speed and on high-friction surfaces. Most (but not all) systems calling themselves "4WD" offer a low range set of gears. Some (but not all) 4WD systems offer both locked and unlocked modes with all wheels driven. Most AWD systems limit the amount of allowable slip between the front and the rear so that you have to lose traction on at least one wheel at each end before you're completely stuck.

As you can see, this is getting complicated. When you start looking at the technologies used, it gets messier yet.

The side-to-side differential action necessary at both the front and rear usually involves a mechanical gear-drive differential at both ends, with or without limited-slip. Front-rear differential action may use a third mechanical differential (and there are multiple designs available), or it may use viscous fluid engagement, or it may use electronically controlled clutches activated by the anti-lock brake system sensors. A traditional 4WD system uses a gearbox (transfer case) to lock the front drivetrain to the rear drivetrain, and forces both to turn at the same speed with no differential action. This has distinct advantages in some situations, and huge disadvantages in others.

Clear as mud? The above is fairly quick and dirty. Amplification and clarification gets even more verbose.

One big caveat for going skiing: Either system is capable of reducing the amount of feedback you get from the surface you're driving on, and may make it so that you're unaware of just how slippery it really is. Be very careful. As has already been noted, vehicles with AWD or 4WD have 4-wheel-brakes, just like everybody else, and you don't stop any better than anybody else.
post #41 of 156
Quote:
Originally Posted by Paul Jones View Post
Are you saying that the prices on these comparisons are similar? A BMW, an Audi and a RAV 4? I wouild rather have an Audi over a RAV 4.

The reason to consider a RAV over a Subaru Outback is AWD vs 4WD, but if the price is the same, hell get the Outback.

Oh no it was more of the systems that I like, for the dollar, I strongly recommended the Subbie. hands down, I have and X5 and it is incredible in the snow and heavy rain, but yes, that's a couple of dollars more. BMW actually has a new improved drive coming out that will restrict some of the power going into wheels that are slipping from dead stops to very slow speeds. This allows better traction on really nasty stuff. If the computer senses spinning it sends gradual power to the wheel.
post #42 of 156
Quote:
Despite what someone in this thread said, all motor vehicles intended for even occasional on-road use allow some kind of speed differential between the wheels on the inside of the turn and those on the outside of the turn, both at the front and at the rear.
Sure, they have a little bit of forgiveness, just not enough to allow for 4wd on dry roads at higher speeds like an AWD/full time 4wd system. In the context of the thread, though, it's an accurate enough statement.
post #43 of 156
Quote:
Originally Posted by JeffW View Post
Sure, they have a little bit of forgiveness, just not enough to allow for 4wd on dry roads at higher speeds like an AWD/full time 4wd system. In the context of the thread, though, it's an accurate enough statement.
Thats not entirely true, my 92 Jeep Cherokee XJ has an NP242 transfer case which allows for 2wd, 4wd Hi (fulltime), and 4wdLow. I can use the 4wd system 100% of the time (wet or dry) with no additional wear to any of the components, the planetary gears in the t-case and the limited slip axles allow for it.

XJguy
post #44 of 156
Quote:
Originally Posted by medmarkco View Post
I actually like the "insanity" of snow .... it's not required for lift-served skiing.
The one time I drove in snow deep enough to billow up over the hood of the Rodeo was to set first tracks to the resort so that I could help get it open for the masses. Fun in a sick sense yes, but basically it was a lot of work. I was told that several people got stuck (and blocked the road)trying to follow my tracks. Those conditions require proper equipment AND skill. It's rare for Pennsylvania, but it happens every few years. If it can happen here, it can happen at any outdoor ski resort. When you drive in these conditions you are basically a RCH away from beaching yourself, overheating the engine or going off road. It's much smarter to watch the weather forecasts and be where you need to be ahead of time and stay there until the roads are cleared. Still, some of us choose to learn things the hard way. Ah, the lure of waist deep freshies!
post #45 of 156
Quote:
Originally Posted by XJguy View Post
Thats not entirely true, my 92 Jeep Cherokee XJ has an NP242 transfer case which allows for 2wd, 4wd Hi (fulltime), and 4wdLow. I can use the 4wd system 100% of the time (wet or dry) with no additional wear to any of the components, the planetary gears in the t-case and the limited slip axles allow for it.

XJguy
So you've got a full time 4wd system, which, in the interest of keeping things simple, is in the realm of the AWD's.
Again, in the context of the thread, all most people need to be able to differentiate is between full-time 4wd/AWD which can be safely operated in 4wd all the time and a true 4x4, which can't.
Those that already know the difference likely also know which one they need or want.
post #46 of 156
Quote:
Originally Posted by verdugan View Post
From the Toyota website:
Electronic On-Demand 4WD with 4WD manual lock switch (Automatically disengages at speeds above 25 mph.)

So above 25mph, you're only on 2 FWD? That would really suck. But if I learned anything from all the posts, it means that above 25pmh you can't have it on/locked all the time, but it would still kick in automatically, correct?
No I think that what it means is that it will go into fulltime 4wd mode, where there is slippage allowed between front an rear axles, to allow for drivability and less wear and tear.
post #47 of 156
For what it's worth, I used to own a '95 Chevy Blazer 4x4, which did exceptionally well in the snow. It had a lever shift, as opposed to push button), and would easily shift in and out of 4WD at 65mph with a lot of control and no ill effects at all. I did it many, many times, and put 130k miles on that truck. The only issue I ever had with the 4wd system was once when the vacuum pump that engaged the transfer case would not shut off, and it didn't come out of 4wd. So I basically had it in 4WD for a week until I could get it fixed. This was in the summer, and I drove it to work. I never had any issues with wearing out the gears or bearings in the transfer case, but that probably only by luck. The issue was covered under warranty. I currently have an 02 Dodge dakota 4x4 quad cab with a limited slip rear diff. It has a push button 4WD system. I've only shifted it in/out of 4WD at highway speeds a couple of times. It took it a few seconds to get the gears lines up, but went smoothly in and out. Always wait until you are on the loose surface to shift in, and shift out before you get back on dry pavement.

For normal commuting to the mountain and as an every day car, I'd probably suggest an AWD system alond with most others here. It's lighter weight, gets better mileage and is lower maintenance (from what I've heard). One other advantage to AWD is the fact that it is basically "on" all the time, so if you are on wet pavement in the summer or hit black ice in the winter, and it starts to slip, it automatically engages the transfer case. You don't want to have a 4x4 in 4WD just because the road is wet. Just being wet, the road is usually too grippy, and will wear on the gears of the transfer case.

The reason you don't engage 4WD on a 4x4 on dry/sticky pavement, is that the transfer case forces the front and rear axle speeds to be the same. If your tires are slightly more worn on the front or back (as is always the case), they won't want to travel at the same speed due to the different outside diameter of the tires. This will cause the tires to get chewed up prematurely and/or the gears in the transfer case to get worn. AWD systems don't lock the gearing to the front axle, as has been mentioned. They use a clutch or fluid (like an auto transmission) to send power to the front. That allows for differences in axle speed front to back.

Comapring the AWD systems available, I'd probably look for something that has a computer controlled anti-skid system, which applies brakes to specific wheels as needed to prevent skidding. I understand these systems to be very effective, and would significantly help cornering and evasive maneuvers on loose/slippery surfaces.
post #48 of 156
Quote:
Originally Posted by XJguy View Post
No I think that what it means is that it will go into fulltime 4wd mode, where there is slippage allowed between front an rear axles, to allow for drivability and less wear and tear.
I agree with XJ. It sounds like, below 25mph, the transfer case can be locked (50/50 power front/rear), allowing for better ability to go off roading or getting you out of a sticky situation. It would also allow for good use of engine braking on very steep off road downhill sections.
post #49 of 156
Quote:
Originally Posted by JohnH View Post
For what it's worth, I used to own a '95 Chevy Blazer 4x4, which did exceptionally well in the snow. It had a lever shift, as opposed to push button)...
Not sure when Chevy went to it, but the 2001 and 2003 S10's I had for company vehicles had 2 dash-mounted buttons. 1 for 4 High, 1 for 4 Low.
post #50 of 156
Quote:
Originally Posted by icanseeformiles(andmiles) View Post
Not sure when Chevy went to it, but the 2001 and 2003 S10's I had for company vehicles had 2 dash-mounted buttons. 1 for 4 High, 1 for 4 Low.
They had it back in '95 on the LT package. Actually, I thought it had 3 buttons - the third was for neutral. I had the LS package with the lever. I like the lever better because it has display lights to show what position the transfer case is actually in, vs where the lever currently is. If I had had the push button, I would never have known that my x-fer case was locked due to the vacuum pump malfuntion, and I would definitely have done some damage to the x-fer case and or my tires.
post #51 of 156
Quote:
Originally Posted by JeffW View Post
So you've got a full time 4wd system, which, in the interest of keeping things simple, is in the realm of the AWD's.
Again, in the context of the thread, all most people need to be able to differentiate is between full-time 4wd/AWD which can be safely operated in 4wd all the time and a true 4x4, which can't.
Those that already know the difference likely also know which one they need or want.
I know what youre saying but in the case of the Jeep (most Jeeps anway), it is a true 4x4 system in that it does have a fully locked setting. Be weary though, Jeep has no less than 3 different 4x4 systems available in their vehicles, not all have full time 4x4, some only have part time.

My bro just bought a base model Grand Cherokee that has no transfer case settings, its awd all the time and as such is not "Trail Rated" by Jeep (has no low and fully locked 4x4).
post #52 of 156
Only one person's experience, of course, but the Subaru I used to own ... well, let's just say there's a reason for the used to own it. On the other hand, I've never been disappointed in any Toyota.
post #53 of 156
Quote:
Originally Posted by JeffW View Post
Sure, they have a little bit of forgiveness, just not enough to allow for 4wd on dry roads at higher speeds like an AWD/full time 4wd system. In the context of the thread, though, it's an accurate enough statement.
Hmmm. I can see I'm causing confusion.

Caution. This could get worse.

We need to differentiate between front and rear differentials, and the third one between the front and the rear.

All vehicles with 4WD or AWD have front and rear differentials. These differentials allow the side-to-side wheel speed differences necessary in all but the worst off-road situations. The front and rear differentials, however, do not, by themselves, allow speed differences between the front and the rear.

4WD may not have any mechanism for allowing differential action between front and rear (although it might); AWD always has some means of allowing some speed difference between the front and rear drivetrains.

A traditional, gear or chain drive, locked-up 4WD system has no "forgiveness" between the front and rear. This is why serious off-roaders like them, and it is why they are dangerous on-road. They are excellent in low-speed, low-traction situations; they are unstable at speed on a high-friction surface.

Many people fail to realize that the rear wheels do not follow exactly the same arcs in a turn as the front wheels. Because they don't, it's necessary to allow them to turn at a different speed than the front wheels if the surface has a high coefficient of friction (i.e., pavement). If the 4WD system is designed to be used only when friction is low (traction is poor), then the compromise in handling is considered acceptable. Either the front or the rear can slip without a problem. On the highway, forcing the front or rear to slip can cause big problems.

The short answer is as before: For skiing, poor weather, on-road, AWD is usually the system of choice. Which AWD? Now you really have to start digging to find out how each one works. They are not all created equal.
post #54 of 156
Quote:
Originally Posted by jhcooley View Post
Which AWD? Now you really have to start digging to find out how each one works. They are not all created equal.
I didn't want to open THAT can of worms. But yes, all AWD systems aren't created equal.
post #55 of 156
Thread Starter 
Quote:
Originally Posted by XJguy View Post
No I think that what it means is that it will go into fulltime 4wd mode, where there is slippage allowed between front an rear axles, to allow for drivability and less wear and tear.
yeah, I answered my own question, but it was too late. Thank you for the reply.
post #56 of 156
Quote:
Hmmm. I can see I'm causing confusion.
Nope, you're just mixing up simplification and confusion.
post #57 of 156
Quote:
Originally Posted by therusty View Post
When you drive in these conditions you are basically a RCH away from beaching yourself, overheating the engine or going off road. It's much smarter to watch the weather forecasts and be where you need to be ahead of time and stay there until the roads are cleared. Still, some of us choose to learn things the hard way. Ah, the lure of waist deep freshies!
You're right, I should have put caveats all over that statement. It isn't the thing anyone wants to do without considering/understanding the consequences if something does happen, and having some plan for what you're going to do about it. Also many years of winter driving helps. No guarantee that life won't get real miserable, real fast, but taking "calculated" risks.

Equipment plays a big part in the decision. Prior to the last two years, I've been driving truck-based AWD or 4WD vehicles with enough ride height to help avoid becoming a beached whale. (Help being the key word - I've beached but was always able to rock out.) Moved into S-10 blazers (4WD) with off-road packages starting in '84, then transitioned into Bravadas with smartrack (AWD) when it arrived in '96. In those 20 years ('84 - '04) I never encountered a storm that stopped me from going whenever I wanted to go.

Those were all "gentleman's" off-road vehicles and not true Bubba off-road vehicles. There's obviously a big difference if you're serious about off-roading. As I moved West to East, my off-road requirements became non-existent so AWD became the better technical solution for me. I don't like the torque steer of FWD so I stayed away from 2FWD -> 4 AWD vehicles. I finally tired of poor handling 85% of the time that I didn't need the ride height and moved into a cross vehicle (SRX AWD) last year. It isn't a quintessential snow vehicle, and I wouldn't recommend it to others for that criteria- but it works. For specific reasons, I narrowed my list to the Touareg, Cayenne, and SRX. Since my father is a retired GM exec., the SRX won out. I'm still learning the limitations - deepest snow so far is 27". I know my snow wings have been clipped ... just not sure how much. The Cayenne/Touareg with PASM would have been a better deep snow vehicle.

If handling would have been my only requirement I would have moved into the car-based AWD platforms. However, I'm fortunate enough to have more than one vehicle which gave me more options.
post #58 of 156
Quote:
Originally Posted by icanseeformiles(andmiles) View Post
Not sure when Chevy went to it, but the 2001 and 2003 S10's I had for company vehicles had 2 dash-mounted buttons. 1 for 4 High, 1 for 4 Low.
It was right around '96 - coincided with the launch of AWD Smartrak Bravada.
post #59 of 156
Have you looked at the Hyundai Santa Fe's? They are in your price range and the 2007's have a totally new, more sporty design. You can get AWD and they come with the best warranty in the world - 10 years or 100,000 miles bumper to bumper. I have a 2002 Santa Fe and I love it, although I don't have AWD. I've never had a problem with it.
post #60 of 156
Remember that when the 4WD feature is engaged, the turning radius becomes far greater. It is the difference between an SL and an SG ski! :

Not true of my AWD Volvo, but my T-100 Toyota truck is NOT going to make any tight turns when the 4X is engaged.
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