Italian law equates snow chains with winter tyres defining them as devices capable of ensuring an adequate level of safety for driving in the cold season. However, their characteristics are not the same and the vehicle behaviour changes significantly according to the solution chosen, especially on snow or ice.
It is the snow that makes the difference
The first major distinction is in the Italian Highway Code itself that, in presence of local traffic regulations, requires motorists to either fit winter tyres on the rims or simply carry snow chains on-board. This means that while four winter tyres can make the difference when braking or cornering on wet or very cold asphalt, a pair of chains stowed in the boot will be of no benefit at all. This applies when driving in most everyday conditions on our roads but it all changes in case of snow.
Think Formula 1
When the snow starts blanketing the tarmac, a driver at the wheel of a car fitting summer tyres will be in a similar predicament to a Formula 1 driver with slicks in the wet. Is it worth taking the risk and carrying on or should I stop and waste time to fit them and then proceed at a slower pace? The right time for the “pit stop” is when the layer of snow becomes compact and is about one centimetre high because this thickness is sufficient to prevent the rings of the chains from coming into contact with the road surface. Otherwise, the rolling of the wheel on the asphalt would compromise grip when braking, without neglecting the negative effect on comfort and on the health of the vehicle itself, compromised by vibrations.
When snow chains can help
If you add the fact that snow chains impose a speed limit of 50 km/h, while with winter tyres you can drive much faster, the feeling is that chains are the cheapest option to comply with the Highway Code providing you never actually have to use them. The reality is different because there are situations in which it could be advisable to supplement the effectiveness of winter tyres. In presence of thick, soft snow or of a sheet of ice on a steep slope, the tyre compound and the slats of the tread may need extra help to advance or avoid loss of control.
A winning combination
Borderline conditions like these may be encountered even for very short stretches, such as the access ramp to your garage at home. When the grip is low, there are no infallible solutions and even the combination of sophisticated electronics and winter tyres cannot work wonders. Snow chains ensure safe traction and adequate stopping distances on steep gradients. In extreme situations like these, the type of tyres fitted on the axle without the chains is essential. In a front-wheel-drive car, for instance, the difference in grip between the drive wheels and the rear wheels will be very marked, with negative effects on stability, if summer tyres are fitted on the back.
Low cost, no thanks
Whether you choose them as the only device to comply with traffic regulations or as a solution to supplement the action of four winter tyres in an emergency, it is important to buy high-quality, type-approved snow chains. Unfortunately, you may be tempted to pick the most economical solution, relying on the fact that you may never actually have to use them, without considering that the low price is determined by the use of low-quality steel and inadequate production processes. Their strain resistance is limited and they can snap after a few miles, potentially putting safety at risk and damaging the bodywork or the suspension system.