Another FWD/AWD/4WD Thread

[oldmaninsc]

Originally Posted By: HTSS_TR
I understand the need of AWD/4WD for snow belt states, but I don't understand why people in Southern California bought MB 4-Matic (MB's AWD), Audi AWD and BMW AWD ... We never have snow here (may be once a century at less than 1/4") and less than 10-15 rainy days a year.

What are the advantages of AWD/4WD over regular 2 wheel drive(rear) on dry and smooth road ? None that I know.

I agree and have often wondered the same thing, but in all fairness I guess we should remember that some people do like to go to the local mountains in the wintertime, and some people do move here from the snowy states.
But I have heard people who bought them just because "someone" told them they were "safer".

 

[IndyIan]

Originally Posted By: Hokiefyd
Originally Posted By: JHZR2
How does one discern the utility of the AWD system versus its FWD baseline?


FWD would not do this inline from a stop.


Well, I couldn't drop the hammer off the start in my Neon like that guy did, but that looked like pretty ideal snow tire traction conditions. With a very carefull launch my Neon might have been able to start on that hill, and if there was any run into it I'm sure it could go up or maintain speed. Technology can help stupid driving a little but some driving skills and experience can help a fwd or khrappy "awd" car get where you need to go.

We happen to have the very same snowtires on both our cars and at low speeds the Tracker can do all sorts of climbing on icy back roads, or in deep snow, that the Neon can't even dream of. On our regular public roads though, in any conditions other than sheer ice, I've never had a problem getting around with FWD and snows. If our own personal driveway didn't require 4wd for a half a dozen days a winter, we probably wouldn't bother having a 4wd vehicle.

 

[Hokiefyd]

An AWD system is just another tool in the tool bag. You can cut pressure-treated 4x4s with a hand saw, but a power mitre box makes it easier. How often do you cut pressure-treated 4x4s? If very often, or if you just want the tool, a power mitre box would be a good investment. If you rarely ever cut that type of wood, a hand saw can get you by.

This is no different. AWD is a tool to help you along. Snow tires are tools to help you along. Certain skills and experience are also tools to help you along. Any of the three above can improve how a car gets along on snow, but every time you add another tool to the job you get an increase in capability.

The original poster asked if AWD really improves traction over FWD (or at least that's the way I read it). The answer is undoubtedly "yes". Snow tires also help; there's no question about that. But the original question was the context in which I posted that video. You have two small SUVs on typical crossover/SUV type tires and put 'em on the hill. The FWD one may not even make it. The AWD one climbed it with relative ease.

 

[JOD]

Originally Posted By: JHZR2
Is anyone really going to crest a hill covered in snow better in one versus the other?


All else equal, "yes". Is it worth it? I guess the answer is the same as it is to most things: "it depends".

I have the unique experience of driving a ton of miles on the same car, both as FWD and AWD (by "the same car", I mean the exact same car, just with the drive shaft removed). Overall, I preferred to have the car FWD. It felt more peppy, gave better fuel economy and had less maintenance. The flip side is that going up steep stuff in snow was much more difficult, and in some cases not possible, without snow tires.

Thing is, in my situation (I can drive to snow but live in rain), AWD and all-season tires is a nice combo. I'll go up to the snow maybe 10-15 times a year, and locally I'll see maybe 5 days of snow a year--not enough to really bother with snow tires.

So ultimately, I think it depends on your driving conditions, as well as the cost, fuel economy hit, durability and maintenance requirements of your AWD system. I'm guessing for most people and most situations, FWD with snow tires makes more sense.

 

[JHZR2]

Originally Posted By: Hokiefyd
Originally Posted By: JHZR2
How does one discern the utility of the AWD system versus its FWD baseline?


FWD would not do this inline from a stop.



I dunno. I've gone up some fairly steep hills just fine in my Saab, even my 318i! Snow tires help, but I've kept a straight line.

No need to play race at driver flooring the pedal up a snow covered hill, I see very little practical utility in that.

 

[Hokiefyd]

As you know, it takes very little throttle to induce wheelspin on slippery surfaces. He did it just as I would have: give it enough throttle to generate some wheelspin and engage the AWD system, and keep in the throttle to maintain the tires' forward momentum and the vehicle's forward progress going up the hill.

You could also observe that the rear wheels engaged nearly instantly when front wheelspin was sensed (probably the RF wheel). There's very little delay with these types of systems.

 

[MrRPM]

My first few years of driving in snow was with FWD cars, after owning my jeep for 1.5 winters (yes its 4wd not awd) i told myself i would never own another FWD car again. for my life style with the area I live in its a major thing for me. It turns winter from a very stressful thing to an enjoyable fun thing. i no longer worry about getting stuck and not being able to make it to where im gong.

In a fwd car all it takes is a snow drift from some wind, or a big hill, or a big over sized truck that requires you to pull off the path a bit and into unplowed snow and boom, your stuck. If your going to slow you get stuck if your going top fast you cant stop. its just not fun. the jeep doesn't have any of those problems.

 

[LoneRanger]

I might take a FWD car wearing new Nokian Hakka's or Bridegstone Blizzaks over an AWD car wearing something like Firestone Affinity's with some wear on them. Tread depth and design makes a big difference. Bottom line though is if you do have a set of dedicated winter tires with good trear depth on a decent 4WD or AWD system like a Jeep, Subaru, Toyota 4Runner or FJ, (probably others not playing favorites just cant enumerate them all at the drop of a hat) etc, you're going to be pretty unstoppable in snow until you high center it, or encounter an unusually steep grade.

 

[MCompact]

Originally Posted By: HTSS_TR
I understand the need of AWD/4WD for snow belt states, but I don't understand why people in Southern California bought MB 4-Matic (MB's AWD), Audi AWD and BMW AWD ... We never have snow here (may be once a century at less than 1/4") and less than 10-15 rainy days a year.

What are the advantages of AWD/4WD over regular 2 wheel drive(rear) on dry and smooth road ? None that I know.


As I said in another thread, AWD is a BIG selling point for those brain-dead imbeciles who say things like, "I'd really like a RWD car, but I need something that I can drive in the rain."
Those pathetic fools should be required to exchange their operators license for a bus token.

 

[IndyIan]

Originally Posted By: Hokiefyd
As you know, it takes very little throttle to induce wheelspin on slippery surfaces. He did it just as I would have: give it enough throttle to generate some wheelspin and engage the AWD system, and keep in the throttle to maintain the tires' forward momentum and the vehicle's forward progress going up the hill.

You could also observe that the rear wheels engaged nearly instantly when front wheelspin was sensed (probably the RF wheel). There's very little delay with these types of systems.

In a very limited traction situation though(the video is not), the need to get some wheelspin to engage the other tires can be the difference between sitting on two icy patches or driving away. Or the difference between sliding sideways further into the ditch or driving away...
Wtih snow tires you can get away with some wheelspin before making patches of ice, but not with all seasons in my experience.
I find when I drop a rear wheel into a ditch when I'm doing a 12 point turn on the wrong icy cottage road, how gently you can engage the clutch is the determining factor in creeping out of a mess when you have real 4wd. Spinning the tires is a recipe to get out the shovel or push...

 

[rjundi]

I have owned FWD with winters, primitive but effective Subaru AWD with winters, and now advanced AWD with all-seasons.


My family's place is on a steep hill where you climb approx 1000' over 1.5miles of gravel roads. FWD even with winter tires simply slips and slides all over. I have an advanced AWD (Acura SH AWD) and it does extremely well even with decent all-seasons in terms of climbing. But also grasping road as it sends torque up to 100% left/right rear wheel to keep from kicking out if you push it around corners. The same is true of my wife's Subaru with full time AWD and Conti ExtremeContact DWS. You can fly down those gravel roads and climb the hills without drama.

Also I find FWD with winter tires can get stuck in really deep snow. Where AWD even though with decent all-seasons always finds a wheel with some traction and you move.

Another cool feature in my vehicle is on steep hills it senses that and runs up to 70% torque to rear driving wheels. In normal driving on pavement it flips to 70F/30R.

Another place it was AWD ftw was a in grass or field parking lots during fairs or festivals when it rained. My Subaru had no issue clawing its way out. FWD even if it had winters would fail. But good thing is folks around to push.

 

[rjundi]

Originally Posted By: HTSS_TR

What are the advantages of AWD/4WD over regular 2 wheel drive(rear) on dry and smooth road ? None that I know.


Some AWD can torque vector meaning send 100% power to individual rear wheel to correct understeer. Sort of the next iteration of stability control. My Acura MDX has it and can do .86G on a skidpad apparently with 18" all-season SUV tires.

 

[LoneRanger]

Three different approaches to AWD:

http://www.automobilemag.com/reviews/12_...heel_drive.html

Link is to page 3 which summarizes the AWD system of each. Page 4 is sticker price and etc, page 1 and 2 a blow-by-blow of the test course and off-roading, etc.

 

[Pablo]

How good is the Subie Imprezza AWD set up?

At least it gets 27MPG or so.

 

[JHZR2]

Originally Posted By: rjundi
Also I find FWD with winter tires can get stuck in really deep snow. Where AWD even though with decent all-seasons always finds a wheel with some traction and you move.


Of course you will. The ground clearance of a typical FWD car is much lower than most AWD vehicles short of an Audi or similar.

Thus my question about cars like CRV, Explorer, etc., where the getting stuck because the car is literally dragging in the slow is less of an issue.

 

[rationull]

Originally Posted By: MCompact

As I said in another thread, AWD is a BIG selling point for those brain-dead imbeciles who say things like, "I'd really like a RWD car, but I need something that I can drive in the rain."


For me it was "I'd really like a RWD car, but there were none on the market that meet my criteria in my price range." I have a Subaru, but practically never have to deal with real weather. There's an off chance the car might see snow once a year or so on a trip, but that's basically it. I don't really buy what some people say about "needing" AWD in the rain, or even about it being an advantage in rain based on my experience so far, if you're driving sanely.

But what it does have is 50% torque to the rear wheels all the time via a straightforward mechanical setup, a very nice point-and-shoot feeling around corners, and no torque steer. A more satisfying drive than its FWD competition, IMO.

I realize this is slightly off topic given the OP was focused on weather issues, but this was my reason for choosing AWD despite the cost, mpg, weight, and complexity penalties. Doesn't address the topic of BMWs and MBs, which IMO, are better left RWD.

 

[JHZR2]

Originally Posted By: rationull
I realize this is slightly off topic given the OP was focused on weather issues, but this was my reason for choosing AWD despite the cost, mpg, weight, and complexity penalties. Doesn't address the topic of BMWs and MBs, which IMO, are better left RWD.


But it is good insight. Yes, I am talking about useful vehicles. As much as some would like to market them as such, these are cars, modern station wagons, sedans with a "trucklike" body on them to serve a more utilitarian way, with FWD and AWD options.

I keep my German cars RWD, thank you very much (unless it was an ML350 or X5 diesel).

 

[rjundi]

Originally Posted By: JHZR2
Originally Posted By: rjundi
Also I find FWD with winter tires can get stuck in really deep snow. Where AWD even though with decent all-seasons always finds a wheel with some traction and you move.


Of course you will. The ground clearance of a typical FWD car is much lower than most AWD vehicles short of an Audi or similar.

Thus my question about cars like CRV, Explorer, etc., where the getting stuck because the car is literally dragging in the slow is less of an issue.


My majority of experience is low slung Subaru(WRX and 05 Legacy GT) with primitive AWD with LSD rear vs say a Honda Civic and wife's old Nissan.

Our family's place seems to seperate out AWD as its really a test everytime we go. FWD CRV(friends) with winters struggles up a steep public gravel road during mud season. Also the driveway drifts in deep since it crosses an open field. Its plowed when the neighbor gets to it which can be daily with wind and higher banks.

FWD with Nokian winters CRV got stuck in 10" of light snow. My sisters recent RAV4 with all-seasons/AWD and software diff locker motored through. It did struggle when the traction control was working OT and basically slowed it.

My MDX made it however almost slowed itself to a stop due to traction/stability control engaging. Its defeatable and then it works fine.

At my family's place AWD is not really a gimmick. However you can tell what works better than the other but it can be condition dependent.

My favorite feature of my SH AWD getting there is about 3 miles of climbing gravel roads with good corners. It keeps the vehicle from kicking out. The turbo Subaru is blast too especially "hill climb". In sections where cars are not there I blast up to 55MPH on gravel uphill. Then I let the turbo idle down......

 

[refaller]

Not many places like that in NJ. Maybe in the far North West corner. Jeez, even at my grandparents farm in the Poconos there are few unpaved roads. Like I said, I have found the AWD system a little beneficial, but certainly not necessary. My new solution- keeping the ole gal as my beater and buying a RWD "fun" car for cheap. I do not think I will replace the CRV with an AWD option if I ever need to replace it. FWD works fine in this area.

ref

PS- I do enjoy seeing everyone go get milk before snow storms even though I have never seen roads here be "impassable" for more than an hour or so after the snow stops.

 

[LoneRanger]

Originally Posted By: Pablo
How good is the Subie Imprezza AWD set up?

At least it gets 27MPG or so.


I'm seeing an avg or 24-25mpg in mixed city/suburban driving and 28-29 on the interstate @ 75mph. My Forester uses the Imprezza running gear, an actual Imprezza should do slightly better due to more aerodynamically shaped and less weight. EPA sticker said 20/27 so as long as its meeting that, I'm happy. It has the manual transmission 50/50 f/r bias.