4x4 vs. AWD ?

[TruckerAlex]

Hi!

I am looking in to the Sport Track, but I do not know the difference between 4x4 and awd. Can some one explain this? Thanks !

[GSU4x4]

Someone can correct me if I'm wrong but AWD is when your vehicle is always using all 4 wheels to drive with, AUTO 4WD (like on the ST) is when the truck feels like it is losing traction and changes from 2 wheel to 4 wheel drive, but only at lower speeds (less than 45 mph)
My ST has the AUTO 4X4 system and I personally dont like it, I would much rather have a button to allow me to stay in 2WD if I want (like my old '98 4x4 Ranger).

[FLOffroad]

He's correct.
AWD is designed more for keeping traction while on road and possibly adverse road conditions.
4x4 is for offroading, and not to be used on the road (except for the Auto 4WD in the case of Sport Tracs and Explorers)

[SkanlaxJMO]

4wd is a 50% power split between the front and rear differential.

AWD typically has a 60% rear 40% front and that changes when under different acceleration and speeds etc. AWD is a street/ mild weather type system.

[JohnnyO]

The later Sport Tracs and Explorers are not AWD because the front wheels do not receive power all the time, even in 4-Auto. The front end only kicks in when the traction control detects slippage. Personally I find it irritating so when I need 4wd, which I needed a lot of this past winter, I just lock it in 4-Hi and very often I turn the traction control off because when ALL the wheels are slipping it makes the engine take a crap at the least opportune times. This essentially gives you open diffs front and rear and in deep snow my '08 didn't do nearly as well as my old '05 Trac or '02 Ranger did with their limited-slip rears.

[kstrayhorn]

With the bwm, they are the same!!

[rhauf]

geez everybody has a separate explanation.. well here's the right one.


4 wheel drive:
front and rear axle are turned in unison by the transfer case. they ALWAYS turn at the same speed regardless of torque, traction, etc. pros: best traction off road, because power is never taken away from the axle with traction and given to the axle without traction. cons: does not allow for a difference in rotational speeds between from and rear axles. for instance, while turning a corner, one axle (or wheel) is forced to slip due to the difference in distance traveled (the front will make a larger arc around the turn than the rear) so with 4x4 you always have a 2x4 (rear wheel drive usually) option for use on high traction surfaces where this would become a problem (like dry pavement)

AWD (all wheel drive): There is a differential separating the front and rear axles, which allows for a difference in speed between front and rear. AWD is designed for on-road use, giving high performance in low traction conditions (snow, ice, wet roads, dirt roads etc) there is usually a clutch (limited slip) in the center differential, which helps prevent wheel spin on one axle alone. the cons to an AWD system are that it does not perform as well in extreme off-road conditions, it usually cant be disabled (more parts always running) and the biggest con in my opinion is that in most AWD systems, all the tires have to have the exact same diameter or it will damage the center differential. for instance, if one tire is warn down more than the others, you will be forced to buy a whole new set (or risk damaging the system)