AWD versus 4X4

muncybob

The Mrs. insists our next vehicle has one or the other, my only requirement is that it gets around 40 mpg/hwy. There are a few that meet both but my question is does the AWD chew up tires faster than a four wheel drive? I've heard this but don't know if that comment came from real world experience or not.

Tbone289

When you say 4x4, do you mean part-time 4x4?

decal

In a word, no. I assume you are talking about a street vehicle with your 40mpg figure. The bad rap on tire wear comes from big lugged offroad tires driven on the street (not really what they're made for). If you keep your tires properly inflated and rotated they should last upwards of 50,000 miles or more. I drive a full size GMC 4X4 and I get that much mileage from every set of the pretty agressive all-terrain radials that I use.

Syndil

I've got a Jeep Cherokee Sport 4x4. Of course the difference between a 4x4 and an AWD is that a 4x4 operates in RWD mode until you manually switch it to 4x4 when you need the traction. In 4x4 mode all wheels are spun at the same speed, so the road surface must be slippery before you engage 4x4, or you will damage your drivetrain.

AWD is full-time 4-wheel-drive, but with an inter-axle differential that allows the wheels to turn at different speeds. I've never owned an AWD, but it is my understanding that AWD doesn't necessarily wear tires faster, but that if something causes one tire to wear unevenly, all of the tires on the car must then be replaced.

This is because in an AWD system it is important that each wheel have pretty much the same diameter and rolling speed, or the AWD system will behave as if one wheel is slipping all the time, since it will be spinning at a different speed than the rest of the wheels. This can cause components of the drivetrain to wear out more quickly than they should.

I rarely engage the 4x4 mode on the Jeep, even in the winter. It's probably been years since I've used it. Even if I do have to get out of a slippery spot on the roads on occasion, I avoid switching into 4x4 mode if possible, because I'm usually not that far from dry pavement where I'll have to switch back to RWD. I think the last time I used it was at Lake Cumberland, towing a trailer through mud. It's nice to have when you absolutely need it, but it is not a magic replacement for knowing how to drive properly on slippery surfaces.

If this is for the wife... Well, I don't know your wife, but if she's like I imagine most wives to be, she won't want to be hassled with having to decide whether or not to engage 4x4 mode. Get in, turn on car, go.

mhardy6647

I think that the OP wants a Touareg TDI :-)
http://www.vw.com/en/tdi/touareg.html?sem=google

FWIW, Mrs. H has a (nominally) 4WD - not AWD, at least accoding to Ford - Hybrid Escape (2005 model year). It returns about 35 mpg in the summer, and drops to about 29 in the winter. The originally suppplied low rolling friction Continental tires lasted well over 100,000 miles (but they were very noisy and one would assume that low rolling friction and good traction in slush and snow are sort of mutually exclusive). The Contis are also NLA, so we've got the same Michelin all-season tires on there now that Ford used on more recent Hybrid Esscapes. The Escape has done a fine job getting us through New England winters.

My little Fiesta does about 42 mpg summer and 39 mpg winter... but I am not sure it has even one wheel driving all of the time ;-)

Syndil

Ford calls it Intelligent 4WD, but it is an AWD system. Runs in FWD most of the time until it detects slippage, then engages the rears.

I think the reason they call it 4WD instead of AWD is pure marketing, since it is an SUV-shaped vehicle.

muncybob

Tbone289 wrote: »

When you say 4x4, do you mean part-time 4x4?

Yes, put it in 4 wheel only when needed.

Willow

A big chunk of small-mid size suvs use 4wd with the fwd taking most of the work until it detects slipping or when starting from a dead stop. Our rav4 is like this, then we also have the option of having it in 4wd lock upto 40 kms/h then it switches back to auto detect mode/fwd.

Joe08867

A Subaru or what MHardy suggested. If you have to have 4wheel capability and get the mileage.

Jstas

*SIGH*

The difference between a 4WD system and an AWD system has nothing to do with the power distribution, front-wheel or rear-wheel bias. 4WD typically drives all the wheels at the same rate. AWD uses viscous couplings which are not physically connected like 4WD and can therefore adjust the coupling to provide a bias towards the front, rear or either side. The full-time 4WD uses clutch packs like a limited slip differential to provide better economy by driving only one axle under normal driving but still allowing 4WD capability in conditions where traction is at a premium.

A 4WD system incorporates the use of a transfer case driven by gears and/or chains and sometimes clutch packs. An AWD system uses a viscous coupling and works like a series of torque converters and clutch packs.

AWD and 4WD do not chew up tires unless something is wrong or out of alignment.

I have an AWD vehicle, a part-time 4WD vehicle and a full time 4WD vehicle. None of them chew up tires any faster than my 2WD trucks or the 2WD/FWD passenger cars.

You should make your choice based on needs that the vehicle needs to fulfill. A heavier truck (usually more than 4500 pounds) will typically have 4WD either part or full time. It needs 4WD because to build an AWD system for it with a viscous coupling it would have to be pretty large and heavy and wouldn't be very reliable lumbering around all that weight. An AWD vehicle does not need to handle a large amount of weight typically and isn't usually a tow rated vehicle either. They are typically less than 4500 pounds.

There are exceptions but they are typically very expensive like the mentioned Toureg TDi.

If you need to tow stuff, look for something with 4WD. If you just want foul weather stability, a crossover or something like a Subaru or Audi should be all you really need.

Glowrdr

Get an Infiniti :cheesygrin:

Wife has a RAV4 (coming from a Suzuki Grand Vitara) - Not saying that all women are the same (if this is wifeys vehicle) - but I/We personally like the AWD. It's instant, and just "there"

The wife had a 4x4 GV, and she either didn't use it when appropriate, or just left in in 4x4 all the time. The AWD is a no brainer. I'm actually pretty impressed with the driving capabilites of her vehicle. I came from a Dodge Ram ('04 quadcab) and hers is a better driver than mine was.

Also - I think just about all 4x4's nowdays have a limited slip differencial in them. This is why there is auto-4, 4 high and 4 low. 4 low locks the differential so all 4 tires spin at the same time. 4-high includes a limited slip for high speed (otherwise you wouldn't even be able to turn) and the auto is just that - it monitors tire slippage and engages when needed. I actually prefer 4-high over auto, but auto is a good backup I guess.

gdb

Quattro

bikerboy

What will get 40mpg and awd? My 04 subaru wrx will get 26mpg on the highway with my wife driving. If I drive it with the access port in hp mode I get 18-20mpg in the city.

muncybob

bikerboy wrote: »

What will get 40mpg and awd? My 04 subaru wrx will get 26mpg on the highway with my wife driving. If I drive it with the access port in hp mode I get 18-20mpg in the city.

I think you are right, after doing some searches today it looks like I either have to compromise on the mpg or convince her she doesn't need awd/4wd. This wouldn't be hard to do if she would drive the truck!

F1nut

I rarely engage the 4x4 mode on the Jeep, even in the winter. It's probably been years since I've used it.

It is a good idea to engage the system at least a few times a year to keep things moving.

brgman

F1nut wrote: »

It is a good idea to engage the system at least a few times a year to keep things moving.

+1.you need to work it for sure.another issue that comes up often is that the auto kind use vacuum lines and if one gets old or pinched and leaks it is a B^tch to fix.Manual hubs are best but you are not going to find them on any of the fancy shmancy stuff.

Danny Tse

bikerboy wrote: »

What will get 40mpg and awd?

The all-new Subaru Impreza is rated at 36 mpg highway with AWD.

Syndil

According to Edmunds, the Impreza is the only car that even comes close to 40 MPG with AWD. Looks like your only choice. New, anyway. Just avoid the gee-haw WRX. Next in line would be a Saab 9-3 at 33 MPG.

Jstas

Saab is dead. No new Saab sales. Not an option.

Drenis

I'm just going to toss this in the bunch.

Suzuki SX-4. AWD, 6 speed manual (Sorry i'm biased) and great mileage.

I'd rock one for a daily driver in the winter up here.

zingo

AWD is the way to go as there is no thought involved, just traction. It's not close to 40MPG, but my wife drives a Honda Pilot, and it's the first car she has really LOVED. You can lock the AWD if you choose, but it normally functions in 2WD with all four engaging with slipping tires.

For better MPG, I highly recommend the CRV if you need an SUV.

Syndil

Jstas wrote: »

Saab is dead. No new Saab sales. Not an option.

Plenty of unsold 2011 Saabs still on dealer lots. They didn't just throw them out the moment Saab declared bankruptcy.

Tbone289

Syndil wrote: »

I've got a Jeep Cherokee Sport 4x4. Of course the difference between a 4x4 and an AWD is that a 4x4 operates in RWD mode until you manually switch it to 4x4 when you need the traction.

That's not exactly true. What you are talking about there is a part time 4WD sytem. There are part-time 4wd systems and full-time 4wd systems, and both of these were offered on the Cherokee. The only difference between the two is the transfer case--the full-time transfer having a differential system to eliminate binding front to rear.

With that said, I would highly recommend a part-time 4wd system to the OP. There is MUCH less to go wrong with them, as long as you don't drive w/them engaged on grippy surfaces such as concrete. The biggest benefit of a 4wd system over an AWD system, for me, is having a low-range transfer case. If you aren't going offroad and don't need a low range, consider the more durable AWD systems.

Ah, I can't think of a single 4WD vehicle that will get 40 mpg, so fugitaboutit. I'd go for a Subaru.

Jstas

Syndil wrote: »

Plenty of unsold 2011 Saabs still on dealer lots. They didn't just throw them out the moment Saab declared bankruptcy.

http://jalopnik.com/5869377/dont-buy-a-saab

That story is over a month old too.

No one is picking up warranties on them. On Chinese companies are interested in gutting it and exploiting established dealer networks.

Don't buy a Saab. You're not going to get a deal on them anyhow.

Syndil

Tbone289 wrote: »

That's not exactly true. What you are talking about there is a part time 4WD sytem. There are part-time 4wd systems and full-time 4wd systems, and both of these were offered on the Cherokee. The only difference between the two is the transfer case--the full-time transfer having a differential system to eliminate binding front to rear.

I understand what you're saying, but to my mind, full-time 4WD is the same thing as AWD. I don't consider it a 4x4 (4WD) unless the differentials are locked. I'm curious to know what distinction you would make between full-time 4WD and AWD.

Of course the definitions we assign to these terms are arbitrary as there is no industry standard defining what they actually mean.

Syndil

Jstas wrote: »

No one is picking up warranties on them. On Chinese companies are interested in gutting it and exploiting established dealer networks.

That is indeed a risk, but a warranty is not valueless. A motivated buyer would negotiate the estimated value of the warranty out of the purchase price of the Saab and possibly end up with a new car for pennies on the dollar. Haven't heard of any reports of that as of yet, but if Saab does not have a stop-gap warranty solution soon, I don't think dealers will have a choice but to accept a low offer. Right now it's sort of a wait-and-see situation since Saab's CEO has been saying that he will try to find a way to honor the warranties. If/when it becomes clear that Saab won't honor the warranties, it's going to be fire sale time.

F1nut

Syndil wrote: »

I understand what you're saying, but to my mind, full-time 4WD is the same thing as AWD. I don't consider it a 4x4 (4WD) unless the differentials are locked. I'm curious to know what distinction you would make between full-time 4WD and AWD.

Full-time 4WD has high and low ranges while AWD does not.

Of course the definitions we assign to these terms are arbitrary as there is no industry standard defining what they actually mean.

Yes there is.

FTGV

You want/need one of these:cheesygrin: http://www.landrover.com/ca/en/rr/range-rover-evoque/

tonyb

Land Rover ?? You couldn't afford the upkeep on those things. My neighbor had one and the thing was always in the shop. Wiper blades cost a couple hundred alone.

Buy an Audi all wheel drive, you'll keep that car 15 years I'll bet.

Tbone289

Syndil wrote: »

I understand what you're saying, but to my mind, full-time 4WD is the same thing as AWD. I don't consider it a 4x4 (4WD) unless the differentials are locked. I'm curious to know what distinction you would make between full-time 4WD and AWD.

The differentials in your XJ Sport are open or limited slip unless you added lockers aftermarket. Lockers were not a factory option in XJs (Cherokees). So aren't you in fact saying that no XJs had 4WD from the factory?

I've never seen a part-time 4WD vehicle that didn't have a center diff lock, the XJ included. Locking the center diff would make it operate exactly the same way as your part-time XJ. Would you say that a part-time 4WD XJ would not be a true 4WD with the center diff locked, even though it operates exactly the same way yours does, and as you describe in your definition? I guess I don't fully understand the separation between 4WD and AWD in your mind either.

You also mentioned that in 4WD all wheels spin at the same speed. Well, that would only be true if the spider gears in the axle differentials were welded, or you were running spools in them. Even lockers allow L&R wheels to travel at different speeds. I certainly don't feel that to be 4WD a vehicle has to have L&R wheels locked together, but it does have to be able to lock F&R axles together.

In my mind, a simple, transfer-case based system that has a low range, center locking (selectable or not) and a RWD-only mode is 4WD. Part-time 4WD fits that definition, but by your definition it's AWD. Other, more complicated systems without low-range transfer cases are what I consider AWD.

I agree that there's no standard, so we can't really come to an agreement here based upon proven fact. I guess I just have a hard time calling part-time 4WD with center diff locked "AWD". However, I don't doubt there have been some vehicles with part-time 4WD labelled as "AWD".

Glowrdr

FTGV wrote: »

You want/need one of these:cheesygrin: http://www.landrover.com/ca/en/rr/range-rover-evoque/

I saw some chick driving one of these just the other day. Had to come home and see what it was. Surprisingly affordable, definately a looker though.