Whats the difference between 4WD and AWD?

[Solodays]

I thought they both run 4 wheels simultaneously, no?

 

[Mide]

AWD does, but I don't think 4WD is like that.

 

[punjabiplaya]

4wd is usually all four wheels receive power all the time. AWD is usually a computer controlled system which shifts power according to wheel slip, turn angle, etc...

 

[shabby]

Originally posted by: punjabiplaya
4wd is usually all four wheels receive power all the time. AWD is usually a computer controlled system which shifts power according to wheel slip, turn angle, etc...

Other way around.

 

[punjabiplaya]

http://www.omninerd.com/blogs/...llacy_of_Snow_Traction

 

[Nyati13]

4WD systems are 2WD/4WD capable, where the center differential can be disengaged by the driver. Most 4WD center diffs are locked at 50/50 power split, but I'm sure there are some that do torque transfer.
AWD systems are "All the Time" systems that cannot be disengaged by the driver. AWD systems all have torque transfer center differentials (most of them quite weak).

So the primary factor on if a system is labeled 4WD or AWD is if the driver can pull a lever or push a button to switch between 2WD and 4WD.

 

[punjabiplaya]

plus all the fancy new symmetric/asymmetric and super handling systems and all that gibberish

 

[herm0016]

Originally posted by: shabby

Originally posted by: punjabiplaya
4wd is usually all four wheels receive power all the time. AWD is usually a computer controlled system which shifts power according to wheel slip, turn angle, etc...

Other way around.

wrong.
most all wheel drive systems are computer controlled, most 4 wheel drive systems are not, they are manual, a gear gets moved to transfer the power. you will find 4wheel drive on trucks, and awd on cars and a few trucks. 4wheel drive is much stronger.

 

[Throckmorton]

It's just marketing. There's no "definition" that distinguishes between 4WD and AWD.

My Grand Cherokee has full time 4WD, with no option for 2WD. When the rear wheels slip, a mechanical "gerotor clutch" system transfers torque to the front, no computers involved AFAIK. When you put it in lo range, it would lock the clutches. The badge on the back says "4WD". The other option for that vehicle is a regular transfer case that lets you select 2WD, 4WD open (slipping tire gets all the power, but good for rain and snow), 4wd with the center diff locked, and 4wd lo with the center diff locked.

 

[iamwiz82]

I usually use the definition that 4WD has a lo gear while AWD does not

 

[marvdmartian]

AWD good for pavement, and other improved surfaces. FWD good for on or off road (and for pulling everyone else out of the ditch when the roads get icy! LOL)

 

[Jumpem]

AWD can be driven on dry pavement. this is useful in the winter when the roads go back and forth between snow covered, light snow, ice, slush, and dry pavement.

With a 4WD truck you are constantly putting it in and out of 4WD. With AWD you don't have to worry about it.

 

[BW86]

I thought most 4wds have a transfer case and most awds don't. I dunno maybe I'm wrong.

 

[Bignate603]

In general usage AWD is a system that is permanently on and the driver doesn't think about it. 4wd allows you switch in and out of it, but should not be used on dry pavement. This is because it lacks a true differential which requires the wheels to slip a little around turns. In the dirt or snow they can, but on pavement they have too much grip. All time 4wd adds a center differential so you can leave it engaged on pavement. Also, all full time 4wd systems I've dealt with allow you to lock the center differential for very slippery situations. Normally, even with full time 4wd I would disengage it as much as possible to save gas and wear and tear on the drive line.

 

[Vic]

AWD originally stood for All-the-time 4-Wheel-Drive.

Usual agreement is that the biggest differences are that 4WD can be disengaged and has a transfer case or locking center differential (and vice versa, AWD cannot be disengaged and has a unlocked center diff). And it's because of the locked center diff that 4WD needs to be disengaged on dry pavement or having the front and rear wheels spin at always the same speed can cause wheel hop on turns. While AWD has a center diff allowing varying wheel speeds and torque distribution front and rear.

4x4 originally stood for 4 speeds to 4 wheels.

 

[ElFenix]

Originally posted by: Vic
AWD originally stood for All-the-time 4-Wheel-Drive.

Usual agreement is that the biggest differences are that 4WD can be disengaged and has a transfer case or locking center differential (and vice versa, AWD cannot be disengaged and has a unlocked center diff). And it's because of the locked center diff that 4WD needs to be disengaged on dry pavement or having the front and rear wheels spin at always the same speed can cause wheel hop on turns. While AWD has a center diff allowing varying wheel speeds and torque distribution front and rear.

4x4 originally stood for 4 speeds to 4 wheels.

here i thought it meant 4 wheels and 4 wheels getting power. 4x4x4 adds 4 wheel steering

 

[Gillbot]

many 4wd systems do not use a limited slip in between the front and rear drivetrains. AWD usually does.

 

[Jeff7181]

The way I keep it straight is by remembering that 4WD means 4 wheels are being driven all the time and AWD means all wheels CAN be driven, but aren't necessarily being driven all the time.

For example... the 2008 GT-R is AWD and all power is sent to the rear wheels unless they lose traction, then it gets split between front and rear and then goes back to only driving the rear wheels when traction at the rear wheels is restored.

 

[rh71]

Have both on my 2 SUVs and obviously 4WD is the bigger PITA as I have to make sure the vehicle is stopped before engaging... plus I can't go above 60mph with 4WD on. They fixed this in later year Rodeos but the whole having to think about it blows. Also have to make sure it's disengaged when the ground is clear again. Handling is definitely affected in 4WD as well - you can feel the tightness when turning for sure. At least it's a true truck frame though and can actually do some good 4-wheeling, though I've only been twice.

 

[Demon-Xanth]

Typically the distinction is the difference between a transfer case or center differential or a viscous coupling. A 4WD in effect will transfer 100% of the torque to the slowest axle (or tire in the case of a locker) while AWD doesn't. There are pros and cons of both arrangements, which is why you see both. AWD is better on the street, 4WD is better when a wheel is likely to leave the ground entirely.

 

[JulesMaximus]

Originally posted by: marvdmartian
AWD good for pavement, and other improved surfaces. FWD good for on or off road (and for pulling everyone else out of the ditch when the roads get icy! LOL)

Funny, the vehicles I always saw in the ditch first when it snowed were the 4WD ones because their idiot drivers seem to think they're immune to the laws of physics.

 

[JulesMaximus]

Originally posted by: rh71
Have both on my 2 SUVs and obviously 4WD is the bigger PITA as I have to make sure the vehicle is stopped before engaging... plus I can't go above 60mph with 4WD on. They fixed this in later year Rodeos but the whole having to think about it blows. Also have to make sure it's disengaged when the ground is clear again. Handling is definitely affected in 4WD as well - you can feel the tightness when turning for sure. At least it's a true truck frame though and can actually do some good 4-wheeling, though I've only been twice.

That's probably twice more than 99% of people who own 4WD vehicles I'd imagine.

 

[Demon-Xanth]

Originally posted by: JulesMaximus

Originally posted by: marvdmartian
AWD good for pavement, and other improved surfaces. FWD good for on or off road (and for pulling everyone else out of the ditch when the roads get icy! LOL)

Funny, the vehicles I always saw in the ditch first when it snowed were the 4WD ones because their idiot drivers seem to think they're immune to the laws of physics.

Originally posted by: JulesMaximus

Originally posted by: rh71
Have both on my 2 SUVs and obviously 4WD is the bigger PITA as I have to make sure the vehicle is stopped before engaging... plus I can't go above 60mph with 4WD on. They fixed this in later year Rodeos but the whole having to think about it blows. Also have to make sure it's disengaged when the ground is clear again. Handling is definitely affected in 4WD as well - you can feel the tightness when turning for sure. At least it's a true truck frame though and can actually do some good 4-wheeling, though I've only been twice.

That's probably twice more than 99% of people who own 4WD vehicles I'd imagine.

I assume your second post doesn't include the people in the first post that go off road unintentionally.

 

[JulesMaximus]

Originally posted by: Demon-Xanth

Originally posted by: JulesMaximus

Originally posted by: marvdmartian
AWD good for pavement, and other improved surfaces. FWD good for on or off road (and for pulling everyone else out of the ditch when the roads get icy! LOL)

Funny, the vehicles I always saw in the ditch first when it snowed were the 4WD ones because their idiot drivers seem to think they're immune to the laws of physics.

Originally posted by: JulesMaximus

Originally posted by: rh71
Have both on my 2 SUVs and obviously 4WD is the bigger PITA as I have to make sure the vehicle is stopped before engaging... plus I can't go above 60mph with 4WD on. They fixed this in later year Rodeos but the whole having to think about it blows. Also have to make sure it's disengaged when the ground is clear again. Handling is definitely affected in 4WD as well - you can feel the tightness when turning for sure. At least it's a true truck frame though and can actually do some good 4-wheeling, though I've only been twice.

That's probably twice more than 99% of people who own 4WD vehicles I'd imagine.

I assume your second post doesn't include the people in the first post that go off road unintentionally.

Clearly they aren't the same thing. Contrary to popular belief, it is possible to wreck a 4WD vehicle by skidding off the road.

 

[Demon-Xanth]

Originally posted by: JulesMaximus
Clearly they aren't the same thing. Contrary to popular belief, it is possible to wreck a 4WD vehicle by skidding off the road.

Around where I learned how to drive there were these things that we used to keep cars from going too far off the road. They were called trees. Didn't matter how many wheels were being used to drive it, the car always lost.


...and yes, my previous comment was being facetious.