NGC - Rear wheel drive w/ Snow tires vs. AWD w/ all season tires

[Madtownguzzi]

Subaru All Wheel Drive Traction Testing Video. I have a 2008 RAV4 AWD which is OK in the Wisconsin winter but Subaru beets it in this test.

https://www.youtube.com/watch?v=kRniF4JQN2U

[Kev m]

That's one of the videos I was referencing... Not the first time it's been linked here... Maybe not even the second. But it's a great demonstration!

[charlie b]

So,back to  the OP.

Just what do you want to do with the car?  You are in the NE part of the country, but, you mention driving 100mi in a snowstorm.

That still leaves a ton of information out.

If you only want to drive in the snow once or twice, and it is on plowed and sanded highways, then just about any car will do it, even with standard road tires.  If you need a "get home" option then carry chains.  Did that for many, many years and they 'saved' me several times.

The question also seems to be from some sort of 'bet'.  As in, I have AWD so I can go where you can't, even with snow tires.

As stated before, going is only part of the problem.  Yes, a good AWD or 4WD (like a Subie or my truck) is different than some others, like my Honda Element.  And, yes, they will go forward when others cannot.  Snow tires make a difference, on snow packed and icy conditions.  In deeper stuff, not so much.  

The problem is turning and stopping.  For that is makes less difference to how many wheels are driven than the tire, so snow tires would be better.  How much better depends a LOT on the specific conditions.

Off road tires on the truck are good for snow pack, not good for ice.  All weather are better on ice, but, not as good as snow tires.

If I had to choose to go 100 mi on an unplowed road (with little traffic) with 10" of snow then I'd take a Subie on all weather tires rather than just about any REAR wheel drive with snow tires.  But, if I had a FWD drive vehicle with decent traction control and snow tires I would not feel under equipped either.  The FWD might not be able to keep going forward if you include things like a 10% grade,but, for most interstate and US highways it would work fine.

And, yes, I have logged thousands of miles on snowy and icy roads with FWD vehicles on all weather tires.  Not as many inclement weather miles on my Subies, but, enough to know the difference.

As an aside, going up my driveway in winter is a lot like that traction control test, only driveway is a little steeper  :D  Honda's system sucks compared to Subie's and the truck.

And snow tires make no noticable difference at all when under the snow and ice is frozen mud and gravel :D  :D  :D

[MotoGuzzi]

Subaru All Wheel Drive Traction Testing Video. I have a 2008 RAV4 AWD which is OK in the Wisconsin winter but Subaru beets it in this test.

https://www.youtube.com/watch?v=kRniF4JQN2U

Does your 2008 RAV4 have a locking center differential? And if so, would it have helped it up the ramp in that demo?

[Kev m]

I'm pretty sure the RAV4 never came with a locking center differential (as can be said for MOST of the FWD based AWD systems, but I think there were a few exceptions).

A locking center diff would assure some ratio of power is split between the front and rear wheels (usually 50/50).

So in that test it would have assured about half the power went to the rear axle. However what happens at that point would determine if it made a difference in the test. Does that power just go to the one wheel that is free spinning without traction, or does the vehicle have a way to force that power to the wheel with grip (a locking or limited slip rear different, brake traction control, etc).

A traditional 4wd truck without a locking or limited slip differential or any braking traction control is basically only capable of driving TWO wheels at any given time.

Put it in a situation where 3 wheels have ice under them and you might not move at all because on each open axle the one wheel with the least amount of traction will just keep spinning and the one with traction won't move as all the power is going to the one that is slipping. So a traditional 4wd truck might have a problem on that test as well.

That is actually why when I bought my first Jeep (my old 99 WJ GC) I opted for a model specifically with Quadra-Drive. I mentioned it earlier in this thread. It was then a brand new system they had just developed that contained 3 variable locking differentials - 1 in the transfer case, and 1 in each axle. You could literally put it on a hill with ice under 3 tires and it had the ability in nearly an instant to direct effectively 100% of the engine power to the ONE wheel that still had traction. We used to go out an play in blizzards a lot in that one, as well as some trails and rock quarries. It would just push through snow as high as the bumper, it would climb loose shale inclines. I remember one time we stopped in the middle of a quarry thinking we'd get out and look around, but when we each stepped out of the Jeep we sunk about a foot into the mud. We quickly (and messily) scrambled back in hoping that we weren't stuck, but the Jeep didn't care at all and just drove out of that pit like we were on solid ground.

In contrast I had a old Chevy Blazer as a kid that I remember being pulled out of a Florida swamp more than once.

[jreagan]

I obviously dislike the tire pressure systems in general.

However the Jeep system is neat, not only monitoring pressure, but it also gives you a digital display of each tire's actual pressure (accurate to less than 1 psi of my analog dial pressure gauge).

It's generally great as you can even watch pressures rise as the tires warm.

But yes, you lose that and/or would have to reprogram with each wheel swap.

And when they are below spec I believe the digital readout that displays that or other data like fuel mileage, range, coolant temp, oil temp, oil pressure, trans temp, Nav directions, etc. Will alternate flashing between the selected display and a warning triangle, which is not only annoying but makes it hard to use the other selected function.

The latest Honda CRVs (and other Honda models) have eliminated the stem-mounted pressure transmitters.  They now rely on the anti-lock wheel speed indicators to detect low pressure (a tire with pressure lower than the others spins at a different RPM).  No more reprogramming.  No more dead batteries in the transmitters.

I use all-season tires on my AWD CRV and did just fine when I lived in NH.

[Zoom Zoom]

Back to the original question: I have had an AWD vehicle since 2003 when I bought my first Subaru. It was not until last winter that I bought a set of rims and had a set of winter tires for said car.

My work vehicle, a 2009 E250 has winter tires on all four corners. It still sucks in the snow! It simply sucks less.

I would take my Subaru with all season tires any day over the RWD van with winter tires. ANY DAY!

Now with the winters added into the mix on the car, it went from great to awesome.

John Henry

[Kev m]

The latest Honda CRVs (and other Honda models) have eliminated the stem-mounted pressure transmitters.  They now rely on the anti-lock wheel speed indicators to detect low pressure (a tire with pressure lower than the others spins at a different RPM).  No more reprogramming.  No more dead batteries in the transmitters.

I use all-season tires on my AWD CRV and did just fine when I lived in NH.

That's similar to the system Mini (and I THINK BMW) used (perhaps still do) on their vehicles with runflats.

Nice simple solution.

Good to know, makes me hate Honda just a little bit less.  :BEER:

[Madtownguzzi]

Does your 2008 RAV4 have a locking center differential? And if so, would it have helped it up the ramp in that demo?

The RAV does have a center locking differential of sorts as explained here. http://rav4world.com/pdf/2006/2006_4wdsystem.pdf
I do not think that in the Subaru test ramp that it would make any difference though as it would only have power to one wheel on each axle. In the real world in deep snow starting out up hill it makes little difference if the center differential is locked or not and once you get over 25 mph it reverts back to front wheel drive.   

[Kev m]

A lot of manufacturers are playing fast and loose with the term "locked".

The RAV4 system is not all that different than the Juke system. The biggest difference is the Juke uses a pair of electronically controlled couplings, one for each rear halfshaft, which allows for individual rear wheel control.

But both systems can't be forced to remain engaged and will vary balance in most conditions. Ultimately control remains with the computers.

[charlie b]

Wouldn't it be nice if they would put a couple of switches on the console so you could manually 'lock' all that electronic stuff.  Like having an ABS switch on a dual sport.  When you just know you are going to be sliding, at least let all the tires spin at the rate you want them to instead of the computer just 'turning off' the power (or applying full brakes).

Rant off. 

PS being an engineer makes me hate other engineers some times :(

[Madtownguzzi]

Wouldn't it be nice if they would put a couple of switches on the console so you could manually 'lock' all that electronic stuff.  Like having an ABS switch on a dual sport.  When you just know you are going to be sliding, at least let all the tires spin at the rate you want them to instead of the computer just 'turning off' the power (or applying full brakes).

Rant off. 

PS being an engineer makes me hate other engineers some times :(

I would sure welcome those switches. The RAV4 has a warning alarm when you start sliding on snow or ice that drives me nuts. Growing up in Wisconsin as kids we could not wait for the roads to get snow covered and go out cruising trying to get stuck and once we did everybody would bail out of the car and push us out of the snow drift. Every time I want to put the RAV4 in a four wheel drift around a corner that dam alarm goes off and dont even get me started on ABS in the snow. I would welcome those switches!!

[segesta]

For what it's worth...
I have a Audi A4 AWD with all season tires, and a Ford Crown Victoria RWD with snow tires. The Audi is much better in snow.

That said, snow tires on a big powerful RWD car like the Crown Vic are an absolute necessity. They don't let you accelerate quickly, but they make the car go where you point it. And control is the most important thing when the snow gets bad.

[Sasquatch Jim]

  My two wheel drive P/U gets along just fine with the tires it came with, the deep snow at 12 to 14 thousand feet is no problem cause I don't drive there.
  I just admire it from down near sea level.

[Eunos9494]

I guess I take a different approach in tires/driven-wheels.  I drive RWD with snow tires from mid-Nov to the end of March.

AWD will help give you traction when you attempt to accelerate.  Snow tires will help you accelerate, turn, or brake.

I've not heard too many people ever say "I would have avoided that accident, if only I could have accelerate on ice faster."

There are some great Youtube videos comparing RWD/AWD and All-seasons/Snowtires.  (I think I remember Tirerack doing one with cars on a hockey rink some time back.)  My own experience is that I can often accelerate faster and stop sooner with my X-Ices than most of the guys I know with Audis and Subarus that still have all-seasons on.

[Kev m]

I guess I take a different approach in tires/driven-wheels.  I drive RWD with snow tires from mid-Nov to the end of March.

AWD will help give you traction when you attempt to accelerate.  Snow tires will help you accelerate, turn, or brake.

To be fair.

AWD WILL help you turn also, and not only in snow or ice.

AWD improves handling and safety year round, on all surfaces.

[rodekyll]

Stopping is more important than going.  I like studded tires for that.

[Kev m]

Stopping is more important than going.  I like studded tires for that.

One could argue you won't have to stop if you can't get going.

Chicken - egg ?

[mach1mustang351]

I'm 100% on board with Studless snow tires, more specifically the Bridgestone Blizzak.  With the Volvos in our fleet the ice and snow may as well be dry pavement.  They are that impressive.  Even my R model with the 6 speed manual.  So I guess that is AWD with winter tires.  There are some studded that work well too.  I have Firestone Winterforce on my AMC Eagle and they work great too. 

[Eunos9494]

Yeah, if it's snow tires on AWD versus snow tires on RWD, snows on AWD will perform better.  If it's all-seasons on AWD versus all-seasons on RWD, all-season on AWD will perform better.  But if you compare all-seasons on AWD versus snows on RWD, I'd put my money on the snows making a bigger difference than the AWD/RWD would.  Who knows?  Just been my experience the tire made the most change.

I found these related videos interesting.

http://www.tirerack.com/videos/index.jsp?video=26
https://www.youtube.com/watch?v=STaximkaQxo

[Kev m]

I found these related videos interesting.

http://www.tirerack.com/videos/index.jsp?video=26

https://www.youtube.com/watch?v=STaximkaQxo

I agree those ARE interesting.

But let's look at a couple of things here.

1. How often (percentage of time) do you drive on pure untreated ICE? Your answer to this may have a lot to do with your choice of tires.

2. The tireRack video was well done, and I don't doubt MOST of what they showed. But they SELL TIRES (especially winter wheel/tire packages) for a living and they didn't tell us what they were comparing? How good were the all-seasons, from the measurements they were a lot closer to the summers than the winters.

In addition the TireRack video purposely chose the worst type of car for such conditions, a RWD. I would argue this was smart of them because a FWD and an AWD would have been closer to the winter tire in 2 of their 3 tests (acceleration and cornering). So kudos to them for not lying, but they are certainly choosing to show tests and data in their own best interest.

3. I've seen the Forester vs. M3 video before. You notice they specifically said SUMMER tires on the Forester, and you notice that it STILL made it up the hill. That says something right there.


So if you look at those videos from another perspective it MIGHT suggest that if AWD and/or All-Seasons can narrow the gap between summer and winter tires. And if you don't expect to drive many miles in THAT severe kind of untreated winter conditions, and perhaps if you slow down and leave a greater following distance, just perhaps you'll be FINE with AWD or FWD and all-seasons.

Just another perspective.

[Rough Edge racing]

 Slippery road traction begins with the driver...A skilled driver in a two wheel drive PU truck is better than a unskilled nervous driver in any all wheel drive vehicle. Just take a look what happens in areas where snow is uncommon and the sheer number of AWD vehicles off the road  when it does snow...

[charlie b]

Depends.  I'd rather have AWD and all season tires than RWD and snow tires.  Done both.  Hate RWD in icy stuff even on snow tires.  Now, if you throw the Beetle or Porsche in there then maybe I'd be OK with RWD and snow tires.  Or add studs to the tires  :)

The videos were interesting but not really conclusive for me.  RWD definitely needs snow tires and regular tires suck for 4wd in winter.  Too bad the second video wasn't with all season tires as the do a little better.

[rodekyll]

One could argue you won't have to stop if you can't get going.

Chicken - egg ?

True, true.  So you advocate staying at home for the winter eating chicken?    :D

Assuming though that we don't want to hibernate, one can also argue that in the snow or ice, you're more in control of your get-going than you are in your have-to-stop.  The three blocks it might have taken to safely accelerate 0 -> 25mph might be reduced to three car lengths on the 25mph -> moose side of the equation.  I appreciate my studs for that.

[Kev m]

Agreed!

Winter winter chicken dinner!

[BrianK]

Boston here.  We get winter.

The first time I tried to take a corner in my (FWD) Saab, I turned the steering wheel to ABSOLUTELY NO EFFECT.  Massive understeer.

With Blizzaks, the Saab is unbelievably sure-footed all winter.  My wife had an AWD Audi A6 with snows, which has to be close to the gold standard in this regard.  I'm not sure it was much better than the Saab.  So to me, it's the tires that are the main factor (and RWD does suck on anything but dry pavement, but you don't necessarily need AWD or 4WD - although I'm a big fan of both).

All season tires in real winter (you guys from south of Pennsylvania, just be quiet)?  I don't care how many driven wheels you got, they'll all be spinning helplessly around here.

[Kev m]

No no, when we were running snows on everything we had a Jeep Cherokee, a Subaru Baja, and a Mini Cooper S. Aside from the Cooper being better at handbrake turns on ice, the Baja and Jeep were SIGNIFICANTLY better at being hooligans or daily drivers in severe weather.

[rboe]

But, at the video's are pretty good at showing, (and years of driving in the winter in Minnesota) snow tires are superior on everything. Even all season tires pale compared to all snow tires. It also shows that even the lowly rear wheeled drive car, with good snow tires (but not all, Mom had this big V8 Buick Skylark that was stupid in the snow; too much power, too much weight in the front) will do just fine in snow - with a skilled driver.

After all, that is pretty all we had for years, 4WD being a very specialized vehicle. When it was really bad out, you simply stayed home.

[Kev m]

But, at the video's are pretty good at showing, (and years of driving in the winter in Minnesota) snow tires are superior on everything. Even all season tires pale compared to all snow tires.

But I continue to argue it may suggest that, but doesn't PROVE that because we have no idea if they choose the best or worst examples of each style of tire.

My personal experience suggests that they chose a worse than average all season for it to be so close between the too.

But again and again, yes, true winters can be an advantage from a tire standpoint.

[Aaron D.]

I suggest practice. Back before we became barbarians and shopping mall parking lots were empty on Sunday, I taught snow driving techniques I'd been practicing for a long time.

Understeer was no problem with a good handbrake. Now cars are coming with 4 wheel emergency brakes, so you need to learn to upset the car a bit if it understeers, and get the rear around.