Quote:
Originally Posted by xoxoxoBruce
This is where you're fucked up, 4 wheel drive does NOT interconnect the 4 wheels to all turn together. 4 wheel drive is a misnomer, it's actually 2 axle drive. Each axle has 2 wheels (except dualies but forget them), and between the 2 wheels is a differential, like all cars.
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Correct until you got to the part about "like all cars If it had a differential like all cars, then the only wheel that spins is the stuck one. So that other wheels will also turn, that 4 wheel drive differential must interconnect (lock) the wheels. Also called limited slip differentials. And more infighting between front and rear wheels.
When trucks had hubs, that interconnection was rock solid. If you drove that vehicle at 30 MPH, you could easily roll the vehicle. So that the today's four wheel drives do not routinely roll over, the differential is not locked as firmly. But all wheels must still be interconnected – causing reduce moving safety. It has a limited slip differential. That means wheels still fight each other. And also increase tire wear.
Why tire wear? Because the wheels on four wheel drive are constantly fighting each other. Increasing tire wear. Reduced traction and control at/above 30 MPH. The compromise. Reduce moving safety so that the vehicle can more easily get started.
Safety is secondary on vehicles designed to have less ground clearance than a Humvee and also be less stable. One icy roads, the last vehicle I want to be in is a four wheel drive where all wheels are fighting each other due to limited slip differentials and another interlock between from and rear wheels.
But those local gossip bimbos tell us to believe differently. As you noted, the limited slip differential is why four wheel drive wheels fight each other - causing less control and increased tire wear. That means less control and less safety. That means less braking and tires more easily losing traction during emergency manuevers. Same thing that increases tire wear also means less control when moving on icy roads.
Which do we believe? Advertising or reality? As DanaC demonstrates, a four wheel drive is not about needing to go off road. In most every case, it's about ego. And this myth that such vehicles are safer because they are higher, etc.
A nearby family suffered last week on the way to FL. She caught the left edge of the left lane on I-95 in SC. Because such trucks are so unstable, it flipped when it snapped back onto the road. Only the most unsafe vehicles with less stability flip more often. One of two kids were killed. These trucks are some of the least stable vehicles. Add four wheel drive to make them even less safe in inclement weather.