Is all wheel drive as effective as 4 wheel drive in deep snow ( 2 feet or more)?
Very few passenger vehicles come from the factory with a 2 foot ground clearance, and once you have snow that deep, the snow that is literally pressing on the front bumper and the undercarriage of the vehicle will make it unlikely that any form of drive system will get you out of those conditions.
That being said, in extremely tough conditions, 4WD is going to be more effective, but with snow that deep, I wouldn’t count on anything. If you typically encounter snow that deep, you will need a 4WD truck that has had the suspension raised significantly.
If you have sufficient ground clearance, I’d say, yes, a good AWD system, such as Subaru’s, would be as effective as 4WD in snow of any depth.
Snow is snow. 4WD excels off road, crawling over dirt and rocks. AWD works very well on snow.
Tire type might have more to do with traction under deep snow conditions than AWD vs 4WD.
How often do you plan to drive through two or more feet of snow, and what sort of vehicle do you plan to drive?
Stay home that day and save $3000-$6000…
You need a plow on front…
As stated…all wheel drive is an on road, slippery condition function and DOES NOT function as well as part time 4 wd in those conditions.
You want some wheel spin in deep mud/snow conditions to keep treads clear. The “deeper” the snow, the more aggressive (doesn’t mean too fast for conditions) you have to drive and heavy duty part time works better. BTW…6" of wet snow can be worse than 12" of dry.
Mechanical diff locks, solid axles, aggressive tread and other off road features (but with narrower non floating tires) are helpful as well. Traction control is problematic and should be disabled.
Ground clearance is EVERYTHING !!!
Remember that the less clearance you have the more flotation you will experience, the less traction you’ll have as well. Our Subaru was an animal until snow got to 7+" and then it was as useless as any front drive car.
In reality the only way most vehicles can really handle 2 feet of snow…is with a plow on front and for that you need a part time 4 wd; no awd “weeners” here.
Bottom line…You cannot buy an awd w/0 center lock that will routinely handle 2 feet of snow.
It depends on the AWD system.
An AWD system essentially has a differential in the center that allows the front and back axles to turn at different rates. The trouble is that the center differential has the same problems as a regular differential, in that it can confuse traction differences for you making a turn and send the torque to the wrong axle. So theoretically, with many AWD systems you can get stuck with only one wheel on a particularly slick patch. With four wheel drive, the front and back axles always turn at the same rate when you’re in 4wd, which is why you can’t use it on dry pavement (since you can’t turn), but it also means that you need to get two wheels stuck in order to be truly stuck, effectively making you half as likely to get stuck. It’s a subtle difference, but it is important.
Now the big caveat. Companies like Subaru and Audi have very good AWD systems with multiple limited-slip differentials which make the situation I was describing above almost impossible. Short of high-centering them, it’s practically impossible to get one of those stuck. But, for really deep snow, ground clearance is more important and, unless you’re shopping for a high-end Luxury SUV like a Land Cruiser or something, you’re not going to find a high-clearance vehicle with a good full-time system.
Usually not. 4WD is usually on larger vehicles.