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I remember my dad ranting in our 88 oldsmobile about how stupid all of those 4WD SUVs were, running around so fast in the snow. He would always say that 4WD cou

I remember my dad ranting in our 88 oldsmobile about how stupid all of those 4WD SUVs were, running around so fast in the snow. He would always say that 4WD could help you accelerate, but not help you brake. But whenever he bought tires, he would always get all-seasons. He found out the hard way (by rear ending an SUV) that a lot of those 4WD vehicles that drive so confidently in the snow are doing so not because they rely on their 4WD, but because they can rely on their tires. Tires matter. A lot. For the past 25 years, snow tires have gotten continuously better. I recently tried out a set of hakkapeliittas, and the difference in driving confidence was dramatic. I could actually count on my car to reasonably stop in a way that I've never felt before, even with chains.

linsomniac 7y ago
I had a friend who used to like to say "4WD can help you accelerate but it can't help you stop". I took him out in my '80 Subaru in the snow one day. It had a lever to activate 4WD, and I demonstrated how it would slow significantly faster with 4WD engaged. The reason is that there was no ABS, and the brake proportioning valve would send most of the stopping power to the front wheels, since most of your stopping power comes from them on the dry roads. But in snow, the fronts lock up before the rears are slowing you down much. With 4WD active, the front brakes were connected to the back as well as the front and would use their stopping power as well. Today is a different world though, with ABS. You're right, it's all about the tires. I used to drive an Audi S4 which I would put Blizzaks on in the winter. I would take people out in the snow and blast around, it was amazingly predictable and controllable.
- windexh8er 7y ago
  In your case the engine braking made up for, what sounds to be, a poorly calibrated braking system. Yes, front brakes take the majority of braking load and they are designed that way from a braking distribution standpoint. But you have zero advantage with engine braking in a 4WD system vs properly calibrated brakes because on snow it doesn't matter - it simply comes down to the point where you lose tire tire friction greater than the inertia of the vehicle. ABS works to prevent a lockup of the wheel which reduces the opportunity to use friction even friction has been lost. You are right that some 4WD systems (generally not AWD systems) can have an advantage of engine braking in wet or snowy conditions by not having to use brakes as much. Most drivers overcompensate on braking application in snow or a loss of control situation, which is why ABS works so well against the natural human response. But if you have a driver that is aware of the vehicle mass and the road conditions a proper braking system wouldn't lose out to control of a vehicle being stopped to engine braking in a 4WD system. Most people don't have the driving skill to know when engine braking would even be advantageous over wheel braking. And engine braking done too aggressively is hard to quickly disengage comparative to letting up on too much wheel brake application which can lead to longer periods of loss of control. Ultimately what Porsche lays claim to is outlandish in extreme situations. They can't beat the laws of physics. And unless their car has active tire studding it wouldn't stand a chance against a quarter mile stretch of wet ice at 4 degree decline. Doesn't matter what vehicle, tires or software you've got. That vehicle is sliding to the bottom with no control.
rmason 7y ago
I well remember the first winter with my new company 4WD pickup. Sure I could go much faster in poor conditions. But once I lost control there was no correcting out of it. You were powerless and just had to wait until you slid to a stop or hit something!
linsomniac 7y ago
Re: Hakkapeliittas: They are amazing in the snow and ice, agreed, but terrible on the dry at interstate speeds. Coming off the highway on an off-ramp at 70 on Hakkas is one of the most butt-puckering experiences I've had. After a couple pairs of Hakkas, I switched to Blizzaks, which are not quite as good in snow and ice, but WAY better in the dry. Front Range CO gets some good snow, but not enough days for the Hakkas to be my preference. YMMV depending on snow days in your location.

linsomniac 7y ago

I had a friend who used to like to say "4WD can help you accelerate but it can't help you stop". I took him out in my '80 Subaru in the snow one day. It had a lever to activate 4WD, and I demonstrated how it would slow significantly faster with 4WD engaged. The reason is that there was no ABS, and the brake proportioning valve would send most of the stopping power to the front wheels, since most of your stopping power comes from them on the dry roads. But in snow, the fronts lock up before the rears are slowing you down much. With 4WD active, the front brakes were connected to the back as well as the front and would use their stopping power as well. Today is a different world though, with ABS. You're right, it's all about the tires. I used to drive an Audi S4 which I would put Blizzaks on in the winter. I would take people out in the snow and blast around, it was amazingly predictable and controllable.

windexh8er 7y ago
In your case the engine braking made up for, what sounds to be, a poorly calibrated braking system. Yes, front brakes take the majority of braking load and they are designed that way from a braking distribution standpoint. But you have zero advantage with engine braking in a 4WD system vs properly calibrated brakes because on snow it doesn't matter - it simply comes down to the point where you lose tire tire friction greater than the inertia of the vehicle. ABS works to prevent a lockup of the wheel which reduces the opportunity to use friction even friction has been lost. You are right that some 4WD systems (generally not AWD systems) can have an advantage of engine braking in wet or snowy conditions by not having to use brakes as much. Most drivers overcompensate on braking application in snow or a loss of control situation, which is why ABS works so well against the natural human response. But if you have a driver that is aware of the vehicle mass and the road conditions a proper braking system wouldn't lose out to control of a vehicle being stopped to engine braking in a 4WD system. Most people don't have the driving skill to know when engine braking would even be advantageous over wheel braking. And engine braking done too aggressively is hard to quickly disengage comparative to letting up on too much wheel brake application which can lead to longer periods of loss of control. Ultimately what Porsche lays claim to is outlandish in extreme situations. They can't beat the laws of physics. And unless their car has active tire studding it wouldn't stand a chance against a quarter mile stretch of wet ice at 4 degree decline. Doesn't matter what vehicle, tires or software you've got. That vehicle is sliding to the bottom with no control.

rmason 7y ago

I well remember the first winter with my new company 4WD pickup. Sure I could go much faster in poor conditions. But once I lost control there was no correcting out of it. You were powerless and just had to wait until you slid to a stop or hit something!

linsomniac 7y ago

Re: Hakkapeliittas: They are amazing in the snow and ice, agreed, but terrible on the dry at interstate speeds. Coming off the highway on an off-ramp at 70 on Hakkas is one of the most butt-puckering experiences I've had. After a couple pairs of Hakkas, I switched to Blizzaks, which are not quite as good in snow and ice, but WAY better in the dry. Front Range CO gets some good snow, but not enough days for the Hakkas to be my preference. YMMV depending on snow days in your location.