Need to rent a car tomorrow, icy roads - AWD, or FWD?

[The-Noid]

The reason AWD is generally better on ice is that most of the AWD systems have the ability to transfer power to very specific wheel(s). Every 4WD system I have seen does not have that ability.

Some of the new AWD (all-time) trucks/SUV, from Lexus, Acura and Audi do have this feature and with the added weight, my guess is they are probably better on ice. However FWD, RWD and even the majority of 4WD are probably going to be worse.

 

[QuantumPion]

I think what you are talking about is thin tires that are underinflated.

Thick tires that are underinflated still underperform a thinner tire that is underinflated.

I was referring to driving in snow (or sand) where having too much traction causes a tire to get stuck by digging itself in. I'm not sure why a wide tire would be worse than a narrower tire in such a condition where underinflating either tire is beneficial, you'll have to explain that one to me.

 

[BurnItDwn]

AWD is nice for acceleration. Otherwise, not a big difference.

AWD = drive through 2+ foot deep powder without any noticable loss of traction.
FWD = get stuck, or have to rock car back and forth a bit when snow is higher than your bumper, or when on uneven grade.

If you don't think you'll be driving in much 6+ inch deep snow, then it really don't make a big difference...

 

[ShawnD1]

The reason AWD is generally better on ice is that most of the AWD systems have the ability to transfer power to very specific wheel(s). Every 4WD system I have seen does not have that ability.

Depends which system you're talking about. Usually "4WD" is when the differentials are all locked and all of the wheels spin at exactly the same speed. My friend's Jeep YJ had this and it was incredible on snow, but it really damages the vehicle if you leave it on and drive on paved roads. Full time "AWD" found on a Subaru is similar to the above 4WD but it uses limited slip differentials instead of totally locked differentials. This is ideal for most driving because you can leave it on all the time and it always provides power to all wheels. Bullshit fake 4WD found on vehicles like the "realtime 4WD" on Honda CRVs is just pathetic because they're "active" systems. Rather than being a simple on or off, it stays off until it detects slip then it turns on, and even then it often sucks because it's trying to figure out where to direct power instead of directing power to all wheels. In case you've never seen this before, this is what "active" 4WD looks like. It's horrible
http://www.youtube.com/watch?v=ooQRxlChvMw

I'm talking about driving in snow (or sand) where having too much traction causes a tire to get stuck by digging itself in.

???
If the AWD vehicle doesn't have enough traction to get out then obviously the 2WD vehicle won't have enough traction either.

 

[The-Noid]

I was referring to driving in snow (or sand) where having too much traction causes a tire to get stuck by digging itself in. I'm not sure why a wide tire would be worse than a narrower tire in such a condition where underinflating either tire is beneficial, you'll have to explain that one to me.

Because the car does not float even with the tires underinflated. There is more surface area to the tire so when you do end up on snow that becomes packed you lose traction ability with a wider tire. A thinner tire when underinflated helps to compact snow well still offering some of the floating qualities.

Accordingly from viewing information on Arctic Trucks at approximately 30" of pure powder and using >=35" tires on a lifted vehicle a wider tire would be beneficial in that circumstance as their tires with 9 inches of sidewall and ~14 width have the ability to float on snow a toyota hilux.

If the OP was considering renting an Arctic Truck, driving in 30 or more inches of powder it would be beneficial to have a wider tire otherwise it would not be.

 

[jlee]

Depends which system you're talking about. Usually "4WD" is when the differentials are all locked and all of the wheels spin at exactly the same speed. My friend's Jeep YJ had this and it was incredible on snow, but it really damages the vehicle if you leave it on and drive on paved roads. Full time "AWD" found on a Subaru is similar to the above 4WD but it uses limited slip differentials instead of totally locked differentials. This is ideal for most driving because you can leave it on all the time and it always provides power to all wheels. Bullshit fake 4WD found on vehicles like the "realtime 4WD" on Honda CRVs is just pathetic because they're "active" systems. Rather than being a simple on or off, it stays off until it detects slip then it turns on, and even then it often sucks because it's trying to figure out where to direct power instead of directing power to all wheels. In case you've never seen this before, this is what "active" 4WD looks like. It's horrible
http://www.youtube.com/watch?v=ooQRxlChvMw



???
If the AWD vehicle doesn't have enough traction to get out then obviously the 2WD vehicle won't have enough traction either.

The vast majority of 4WD vehicles do not have locking front and rear differentials.

Yet those AWD Subies are usually the ones that are on the side of the roads first. People think AWD magically makes you be able to take on any roads.

Not up here...then again, people in NH usually know better than to drive their '11 WRX in the snow with OE summer tires.

 

[ShawnD1]

AWD is nice for acceleration. Otherwise, not a big difference.

.....

If you don't think you'll be driving in much 6+ inch deep snow, then it really don't make a big difference...

It's not all about getting stuck. It's about being able to clear intersections or make turns. With bad 2WD traction, making a left turn is virtually impossible. I'm sure you can think of at least one time where you're in the intersection, you're trying to turn left, but there's ice under one of your tires and it causes your car to sloooowly make that turn. So the result is that you're directly in the path of oncoming traffic for probably a good 5 seconds. If some asshole is texting while driving and he doesn't stop for you, it's technically your fault there was an accident because the guy turning left is supposed to yield to the guy texting while driving! Grrr! You could lose thousands of dollars and possibly die all because your car can't clear intersections when there's a tiny bit of ice.

 

[The-Noid]

Depends which system you're talking about. Usually "4WD" is when the differentials are all locked and all of the wheels spin at exactly the same speed. My friend's Jeep YJ had this and it was incredible on snow, but it really damages the vehicle if you leave it on and drive on paved roads. Full time "AWD" found on a Subaru is similar to the above 4WD but it uses limited slip differentials instead of totally locked differentials. This is ideal for most driving because you can leave it on all the time and it always provides power to all wheels. Bullshit fake 4WD found on vehicles like the "realtime 4WD" on Honda CRVs is just pathetic because they're "active" systems. Rather than being a simple on or off, it stays off until it detects slip then it turns on, and even then it often sucks because it's trying to figure out where to direct power instead of directing power to all wheels. In case you've never seen this before, this is what "active" 4WD looks like. It's horrible
http://www.youtube.com/watch?v=ooQRxlChvMw


???
If the AWD vehicle doesn't have enough traction to get out then obviously the 2WD vehicle won't have enough traction either.

Locking diffs you can't drive more than about 10 mph, unless things have changed in the last 4-5 years (haven't been in any suv with locking diffs in a while). My first car was a Land Cruiser with the ability to lock the diffs, it was great when I drove in the ditch like any 16 year old.

 

[ShawnD1]

The vast majority of 4WD vehicles do not have locking front and rear differentials.

You're right that they don't really lock, but there's a lot of friction to resist spinning at different speeds. In the owner's manual for a Nissan Xterra, it says not to exceed 55mph while 4H is engaged; high speed in a high friction system is hard on it.

The downside of the high friction or locked system is that you can't use it all the time. The upside is that it works really really well when you decide to use it.


I'm not sure if my friend's YJ actually locked differentials in 4H, but I know that it would vibrate the vehicle like mad if one tried turning while in 4H on dry pavement. It might not be locked, but god damn does it have a tight limit on that limited slip differential.

 

[BurnItDwn]

It's not all about getting stuck. It's about being able to clear intersections or make turns. With bad 2WD traction, making a left turn is virtually impossible. I'm sure you can think of at least one time where you're in the intersection, you're trying to turn left, but there's ice under one of your tires and it causes your car to sloooowly make that turn. So the result is that you're directly in the path of oncoming traffic for probably a good 5 seconds. If some asshole is texting while driving and he doesn't stop for you, it's technically your fault there was an accident because the guy turning left is supposed to yield to the guy texting while driving! Grrr! You could lose thousands of dollars and possibly die all because your car can't clear intersections when there's a tiny bit of ice.

Agreed, that is what I meant. AWD = better acceleration, but FWD should work.
I have AWD in my car and like it, however, My first 3 cars were all FWD, and I've driven in snow hundreds of times and never had issues other than one time I spun out in 1997.

 

[rh71]

Another thing is that if you get something like a luxury SUV, it is probably going to have big wheels. Big wheels are usually wider, and wide wheels actually do worse on snow and ice.

True in general but it really depends how bad it is. It's snowy here with some patches of ice and I ride on my all-seasons with 315-width 20" rims in the back perfectly fine. Was also fine when we got 15" of snow and they plowed just a little.

In short, I wouldn't worry about what your rental is as long as it's not RWD. I got a Dodge Journey FWD rental a couple weeks back... was just fine.

 

[0roo0roo]

awd gets you started.
stopping has the same 4 wheels as ever...

 

[thepd7]

I'm going to rent a car from Avis and have to do a few hours of driving tomorrow. Since it's icy up in the north east tomorrow, I was wondering if it would make sense to rent something with AWD rather than a regular FWD.

Will it make much of a difference?

Where in the NE? If it's MA it doesn't matter, they keep the roads really clean. If Vermont and/or NH, you'll want AWD.

Bullshit. He said icey, not 4 feet of snow.

Subura's are, by far, the best cars I've ever driven on snow and ice as long as its not more then a foot of snow. WRX is no exception

Just curious, what have you driven beside subarus?

 

[The-Noid]

awd gets you started.
stopping has the same 4 wheels as ever...

Just to be clear your really implying braking hasn't had a quantum shift in the last 20 years? Really?

 

[jlee]

You're right that they don't really lock, but there's a lot of friction to resist spinning at different speeds. In the owner's manual for a Nissan Xterra, it says not to exceed 55mph while 4H is engaged; high speed in a high friction system is hard on it.

The downside of the high friction or locked system is that you can't use it all the time. The upside is that it works really really well when you decide to use it.


I'm not sure if my friend's YJ actually locked differentials in 4H, but I know that it would vibrate the vehicle like mad if one tried turning while in 4H on dry pavement. It might not be locked, but god damn does it have a tight limit on that limited slip differential.

That's what you get when you have a locked center differential and your front and rear wheels turn at a different rate. You'll have issues turning on dry pavement with front and/or rear lockers as well, but what you're describing is normal for any 4WD vehicle in 4WD on dry pavement (which is why you don't use 4WD on dry pavement).

 

[zerocool84]

Just to be clear your really implying braking hasn't had a quantum shift in the last 20 years? Really?

He's saying AWD doesn't help you stop any better. I don't know where you get any of that from those few words he said.

 

[jlee]

Just to be clear your really implying braking hasn't had a quantum shift in the last 20 years? Really?

What zero said. AWD does not help you stop. You still have brakes on four wheels.

 

[The-Noid]

nm

 

[The-Noid]

What zero said. AWD does not help you stop. You still have brakes on four wheels.

Ah I get that. Most new car whether 4wd, 2wd, fwd, rwd is going to have massively improved braking to only a few years ago. Computers and ABS have greatly improved the cars ability to stop on many surfaces.

That is a good point, but that is what snow tires are for...

 

[jlee]

Ah I get that.

That is a good point, but that is what snow tires are for...

Yes, but some people get an AWD car and think 'wheeee, I have AWD and I can do anything!'..then forget that they can't really stop any faster than their Civic did with snow tires.

 

[The-Noid]

Yes, but some people get an AWD car and think 'wheeee, I have AWD and I can do anything!'..then forget that they can't really stop any faster than their Civic did with snow tires.

You are right in that, I am genuinely shocked how poor the driving is in MN these days during the winter. People drive WAY TOO fast on snowy days and ditch all the time.

I am also for fully banning cell phones at least during winter months. There are simply too many things that can go wrong when you have blowing snow on a day in and day out basis.

 

[zerocool84]

Yes, but some people get an AWD car and think 'wheeee, I have AWD and I can do anything!'..then forget that they can't really stop any faster than their Civic did with snow tires.

Do you guys train in snow/ice in your cruisers at all???

 

[The-Noid]

Do you guys train in snow/ice in your cruisers at all???

I am shocked at how well police do in MN with cruisers and RWD cars. I always tell people the reason I keep buying cars with AWD is because I genuinely believe I am not that good a driver in the snow and that no one is. See a lot of RWD BMW's around and I can't imagine they can be great in the snow. Same thing with cruisers. High HP and RWD in the snow can't be great.

If I ever move somewhere warm, first thing I will be doing is buying an M5 as my daily driver though.

 

[ShawnD1]

Do you guys train in snow/ice in your cruisers at all???

I sure hope so. The police would be at a major disadvantage if most of the people are driving to work in FWD cars then are paid to chase people using RWD cars.

 

[rudeguy]

Do you guys train in snow/ice in your cruisers at all???

Ever watch a cop take off when its snowing out? They usually manage a couple of fish tails and throw up a pretty good rooster tail.

Now someone responsible like Jlee...I'm sure he's never kicked his ass end around just to see how far he can travel sideways.

I stay out of these threads on purpose because I hate idiots from Lake Tahoe that try to talk like they know how to drive in snow. The answer is that everyone should go to a safe place and mess around a bit when it first snows. How are you going to know how to drive in bad conditions if you avoid them?