4WD may give you a stable feeling. Snow chains can be said to be the “ultimate equipment” for household vehicles to cope with ice and snow roads.
Why are icy roads dangerous? Low friction, right? 4WD does not increase the friction between the tire and the ground, but only reduces the grip required at the starting stage. If the vehicle is driven forward, the engine drives two front wheels to rotate, dragging the two rear wheels forward, and the grip required for the vehicle to move forward is provided by the two front wheels. The upper limit of tire grip is the friction between the tire and the ground.
In 4WD vehicles, all four wheels have power, so the grip required for traveling will be distributed to the four wheels, and the grip required for a single wheel is smaller. The friction force is determined by the vehicle weight, the friction coefficient between the tire and the ground (determined by the smoothness of the object surface) and the contact area. The vehicle weight is the same, and the contact area is the same (if the tire pressure is unchanged). A smaller friction force means a lower friction coefficient. In other words, 4WD vehicles can travel on smoother roads (mainly starting) without skidding.
What is the function of snow chains? Make the surface of the object more rough, increase the friction between the tire and the ground, not only the friction at the start, but also the braking can provide greater friction. Its anti-skid effect is comprehensive. The 4WD does not increase friction and does not directly prevent slipping. It just reduces the grip required for starting. When you brake, there is no difference between 4WD and 2WD, because 2WD also has four brake calipers, and the four wheels brake together. At this time, the skid resistance is determined by the traction control system, that is, TCS.
Disadvantages of snow chains
4WD has a very limited effect on ice and snow roads. Snow chains are the right remedy, but snow chains are not omnipotent. First of all, there are four common problems in the market:
- 1: Iron chain anti-skid chain: the advantages and disadvantages are obvious. The advantage is that the anti-skid effect is the best, durable, and basically all road conditions can be driving calmly. The disadvantages are heavy, occupying space, difficult disassembly and assembly, and the noise is very loud, especially damaging the tire.
- 2. Steel wire rope anti-skid chain: it can be regarded as a weakened version of the iron chain. It is not as strong as the iron chain, and it has no good anti-skid effect. However, it should be lighter, easier to disassemble, less noisy, and it will also hurt the tire, and the price is relatively expensive.
- 3. Leather anti slip chains: there are two kinds. One is polyurethane anti slip chains. This thing doesn’t hurt the tire, but the anti slip effect is general, and it’s not durable. It breaks after a few times of use. The other is rubber anti-skid chains, which are more durable. The anti-skid effect is not as good as iron chains, and the price is more expensive.
- 4. Plastic type anti slip chains: basically, they will burst when they fall on the ground.
These four kinds of anti-skid chains have their own shortcomings. The tie type can be eliminated. If you live in the South Pole and go out with ice and snow, then the iron chain type is the most stable. Overall, rubber anti-skid chains are more suitable, but the anti-skid effect is slightly higher than that of snow tires, which itself is equivalent to changing the pattern of your tires.
In addition, the anti-skid chain itself is also with “original sin”. There are a few precautions for use, which is actually very painful. You know, anti slip chains must be installed on all four wheels! Even if you are a two drive car, you need to install all four wheels, otherwise the friction between the front and rear wheels is inconsistent, and it is easy to slip out of control when you step on the brake, and sometimes it is even better not to install it! Remember, In addition, the anti-skid chains cannot be used on the road without ice and snow. For example, a section of road has been cleaned, exposing the asphalt pavement. You have to stop here, remove the anti-skid chains, and install them after passing this section of road. It’s very troublesome.