4WD vs. AWD

Looking at various Yukon XL/ Denali models. Is there an advantage to 4WD vs AWD
vehicles? My 97 GMC Suburban will go through deep snow if needed. Will a newer
AWD vehicle or a 4WD "when needed" vehicle perform as well? Advice needed!

RobertS975 wrote:
>
> Looking at various Yukon XL/ Denali models. Is there an advantage to 4WD vs AWD
> vehicles? My 97 GMC Suburban will go through deep snow if needed. Will a newer
> AWD vehicle or a 4WD "when needed" vehicle perform as well? Advice needed!

Two major differences exist between the two, (part-time) 4WD usually implies a transfer case, which is typically locked (gear or chain driven) and a lower gear range. If the AWD system has an option to lock the center diff, then you would have the same
traction options as 4WD. If you find you need low range to get through deep snow (I find low range is a benefit when I get in deep snow), then as long as the AWD system has a low range, then that would also be comparable. Of course there will be
variations, like a limited slip type center diff in AWD.

--
Roger

RobertS975 wrote:
>
> Looking at various Yukon XL/ Denali models. Is there an advantage to 4WD vs AWD
> vehicles? My 97 GMC Suburban will go through deep snow if needed. Will a newer
> AWD vehicle or a 4WD "when needed" vehicle perform as well? Advice needed!

Two major differences exist between the two, (part-time) 4WD usually implies a transfer case, which is typically locked (gear or chain driven) and a lower gear range. If the AWD system has an option to lock the center diff, then you would have the same
traction options as 4WD. If you find you need low range to get through deep snow (I find low range is a benefit when I get in deep snow), then as long as the AWD system has a low range, then that would also be comparable. Of course there will be
variations, like a limited slip type center diff in AWD.

--
Roger

On 19 Jan 2004 21:43:21 GMT, (RobertS975) wrote:

>Will a newer
>AWD vehicle or a 4WD "when needed" vehicle perform as well? Advice needed!

Any system of AWD/4wd that can be used on pavement WILL NOT perform as
well off-road or in real severe conditions. BUT, the vehicle you
mentioned also has true four wheel drive capability, (as well as the
AWD setting), as it includes 4 high lock/4 low lock in the T-case.

(I own an AWD Safari van and I can tell you that while its AWD system
isn't as good as true 4wd, it is about 90% capable. Would be 95% if
it offered low range. Not every AWD system is as good as this one
though.)

Matt
99 V-10 Super Duty, Super Cab 4x4
96 GMC Safari AWD Hi-Top Conversion

On 19 Jan 2004 21:43:21 GMT, (RobertS975) wrote:

>Will a newer
>AWD vehicle or a 4WD "when needed" vehicle perform as well? Advice needed!

Any system of AWD/4wd that can be used on pavement WILL NOT perform as
well off-road or in real severe conditions. BUT, the vehicle you
mentioned also has true four wheel drive capability, (as well as the
AWD setting), as it includes 4 high lock/4 low lock in the T-case.

(I own an AWD Safari van and I can tell you that while its AWD system
isn't as good as true 4wd, it is about 90% capable. Would be 95% if
it offered low range. Not every AWD system is as good as this one
though.)

Matt
99 V-10 Super Duty, Super Cab 4x4
96 GMC Safari AWD Hi-Top Conversion

>
> Any system of AWD/4wd that can be used on pavement WILL NOT perform as
> well off-road or in real severe conditions.

Why?

--
Julian
---------
= Pretentious Sig required =

>
> Any system of AWD/4wd that can be used on pavement WILL NOT perform as
> well off-road or in real severe conditions.

Why?

--
Julian
---------
= Pretentious Sig required =

Let's not forget that in most stock 2WD/4WD vehicles (such as a 1984
chevy pickup) the center diff. locks the front and rear drive shafts
together but there are two more diffs, front and rear, and under most
conditions these differentials only transmit power to either the left
or right wheels. "Peg Leggers" in the drag racing world. In certain
circumstances (when you are traveling perfectly straight with equal
traction on both wheels) you can get the dif to lock up. So even if
you have a 4X4 it doesn't mean you get power to 4 wheels.

Today's AWD systems sometimes sense wheel spin and dynamically brake
the wheels to transfer power "from the wheels that slip to the wheels
that grip". Its a form of anti-lock brakes for accelerating. In
effect you do get power to all 4 wheels.

Josh

Let's not forget that in most stock 2WD/4WD vehicles (such as a 1984
chevy pickup) the center diff. locks the front and rear drive shafts
together but there are two more diffs, front and rear, and under most
conditions these differentials only transmit power to either the left
or right wheels. "Peg Leggers" in the drag racing world. In certain
circumstances (when you are traveling perfectly straight with equal
traction on both wheels) you can get the dif to lock up. So even if
you have a 4X4 it doesn't mean you get power to 4 wheels.

Today's AWD systems sometimes sense wheel spin and dynamically brake
the wheels to transfer power "from the wheels that slip to the wheels
that grip". Its a form of anti-lock brakes for accelerating. In
effect you do get power to all 4 wheels.

Josh

Chris Phillipo wrote:
> In article >,
> says...
>>>
>>> Any system of AWD/4wd that can be used on pavement WILL NOT perform
>>> as well off-road or in real severe conditions.
>>
>> Why?
>>
>>
> Since the front and rear axle are not binded together by a solid
> mechanical linkage in most AWD systems you could end up in a situation
> where all or some of your power is going to only the front or rear
> drive wheels.

Possibly correct, but Matt says it is impossible for a 4WD system that can
be used on-road to perform as well off-road as a part-time system which is
wrong.

My full-time 4WD works very well on-road and has a solid mechanical diff
that locks the front and rear axles together completely making it identical
to a part-time 4WD system when off-road.

--
Julian
---------
= Pretentious Sig required =