Is it better to have a light vehicle or a heavy vehicle when driving in slick conditions?

Question

Normal force (weight) is directly proportional to friction, which would seem to make a heavy vehicle more advantageous. But the mass of a vehicle affects inertia, making acceleration, deceleration, and turning more difficult. That's the trade-off. Which argument wins when controlling for tire tread and wheel drive? Is it too complex to determine without math? I was driving my light pickup and figured having nothing in the bed was better, since a truck is heavy already.

Answer 1

You are correct, but you didn't consider that acceleration, deceleration and turning are also dependent on friction. Your consideration that a heavy vehicle slides farther once it starts to slide has to be modified by the fact that it 'slides harder', that is, it maintains more friction even while sliding than a light vehicle does.



Overall, a heavy vehicle (and remember, the how heavy is not just gross weight, but amount of tire touching the road per unit of weight) is better unless conditions are so slippery that the difference in 'road grab' is negligible.



You might note that snow tires are designed with less of the tire touching the road (the spikes instead of full tread) to take advantage of surface area, hence mimicking the grab of a heavier vehicle.

Answer 2

Control in not as simple as calculating mass. Traction is determined by many factors, such as the type of rubber making contact with the road surface, front wheel versus rear wheel and, in the case of your light truck, whether or not a load is being carried.



In other words, weight distribution is extremely important. Since a truck is DESIGNED to carry loads, optimal control is maintained when the truck is carrying something in back. If it were designed for maximum performance while empty, then a load would tend to destabilize the truck.



Add factors, such as horsepower and when it's applied, speed, and breaking, and the whole calculation gets very complicated. No vehicle can be designed for optimal performance across ALL possible conditions. Best things designers can do is engineer the best possible average for the type of vehicle. Notice, for instance how many more vehicles of different sizes come with all wheel drive, compared to 20, even 10 years ago.

Answer 3

A heavier vehicle is far better in snow and on ice as far as traction is concerned, especially if the bulk of the weight of is over the drive wheels. This also holds true on a heavier vehicle on packed snow as long as there is good tread on the tires as the weight holds the tires tighter to the surface of the road and snow. And of coarse we all know that a heavier truck or car if far safer in case of an accident. Ice is a completly differant story, the heavier vehicle will of coarse take longer to stop than a lighter one simply because of the weight.

Answer 4

Heavy, it allows the tires to get better traction.