On the Safe Side with Snowchains

If you drive your car exclusively on flat ground during the cold season, you can get by on winter tires. In steeper terrain, a set of snow chains must be included in your winter gear to make sure the vehicle doesn’t get stuck on the road in snow and ice. We took a closer look at the latest traction aids.

Snow chains change the driving and braking behavior of the vehicle and therefore require an adapted driving style. Photo: Shutterstock – Checubus

Winter tires are the best insurance for getting your car safely through the cold season. Sometimes, however, stronger traction aids than a coarse tread, sipes, and a cold-flexible rubber compound are needed to stay on the road in snowy winters. “If you’re taking your car on a ski vacation, you should keep a set of snow chains in the trunk for steep climbs and descents in alpine regions, just in case,” explains Christian Koch, an expert on tires and Head of the Analytics Department at DEKRA’s Munich branch. But which chain is the best fit? There are snow chains with square and round links, robust and fine-link models, and those that can be reversed. More sophisticated chains feature thermoplastic protective elements that protect alloy wheels from damage and scratches. In addition, an automatic system is often available to eliminate the need for manual retensioning. Meanwhile, manufacturers are even competing for the best wheel slide protections that manage entirely without solid steel. These are textile systems that cover the tire like a blanket. Until now, these were used as starting aids to help a stuck vehicle out of its predicament.

Textile Systems as Anti-skid Devices

At the beginning of December 2020, the European Committee for Standardization adopted the EN16662-1 standard, which grants textile systems the suitability as anti-skid devices if certified according to this standard. However, it isn’t yet used in all EU countries. In Austria, for example, drivers must still avoid using textile systems if snow chains are compulsory. On the other hand, you’re on the safe side with snow chains that comply with the current Austrian Ö-Norm 5117.

In Germany, for example, the legislator makes no distinction between systems made of metal or textiles. In response to an inquiry from DEKRA solutions, the German Federal Ministry of Transport and Digital Infrastructure (BMVI) states that the German Road Traffic Licensing Regulations (StVZO) define snow chains as devices intended to enable safe driving on snow-covered or icy road surfaces (Section 37 (2)). Snow chains must always be designed and fitted in such a way that they cannot damage the road surface. A requirement that snow chains be made of metal is not included in the German Road Traffic Regulations (StVZO). The law also doesn’t stipulate that snow chains must not be made of textile.

Spring Clip Chains and Stand-Mounted Chains Are the Classics

The classic version of the snow chain is available in two main designs. The spring clip chain is designed for quick and easy installation. The steel hoops are slipped over the tire from above, which works well even in narrow wheel arches. Since the hoops are under tension, the ends join almost automatically behind the tire. The car must then be moved forward or backward about a quarter turn of the wheel until the chain’s clasp is at axle level. Then the snow chain can be tensioned and secured with a clamping chain. The stand-mounted chain, on the other hand, is usually not quite as technically complex as the spring clip chain. Instead of shape-retaining steel hoops, it has flexible steel cables. The installation always follows the same principle: First, the chain is arranged on the ground around the tire. Then the steel cables are connected together, followed by the outer chain at the top and bottom of the tire. The car doesn’t have to be moved to tension and secure the chain. Since each type of chain has its own way of utilizing tensioning elements, hooks, eyes, and fasteners, you should run through a dry practice session before heading out. If you end up using the snow chains for the first time in the middle of a snowstorm, you’ll never manage to fit the chains on the wheels on the first try.

Snow Chains Are Winter Gear Essentials in Alpine Regions

No matter what type of chain you take with you on your trip, there’s only one chain that’s really bad: The one you don’t have with you when you really need it. In fact, in winter driving conditions, a traction aid is part of the ideal winter gear – even if the legal regulations in some countries don’t always require it. In Germany and Switzerland, for example, winter tires are compulsory in certain situations – ice, black ice, slippery snow, and slush.

The following applies to snow chains: If the road is continuously covered with snow and ice, it’s at the driver’s discretion whether or not to fit chains. However, if the blue traffic sign with the stylized snow chain on the tire appears on the side of the road, discretion is over – in this case, the anti-skid aid must immediately be fitted by law. Similar regulations apply in many European countries. In the mountains in France, winter tires can be specifically enforced by a traffic sign. On snow-covered roads, you’ll frequently encounter the combination of the sign for the fitting of snow chains with an additional sign stating “Pneus neige admis” – in this case, winter tires are permitted instead of snow chains. In Norway, for example, the use of snow chains is mandatory for all vehicles exceeding 3,5 tonnens from November 1 to May 1.

Snow Chains on Summer Tires Are a Dubious Experiment

In Italy winter tires may also be enforced on certain routes at short notice if the weather conditions demand it. Special regulations apply in the Aosta Valley, for example, where winter tires or snow chains must be used between October 15 and April 15. In Austria, on the other hand, there’s a rule for passenger cars that winter tires must be fitted in winter driving conditions between November 1 and April 15. The law permits combining summer tires with snow chains on the drive axle as an alternative in case of continuous snowy roads. However, just because the law permits it, doesn’t mean it makes sense from a technical point of view. Tire experts agree that snow chains alone are not a viable substitute for winter tires. Christian Koch therefore advises against such experiments. “Due to the chains, a car with summer tires has a good grip on the drive axle, but almost none on the other axle. In addition, a snow chain doesn’t sit well on a summer tire’s tread – it can slip through the chain when braking and thus significantly increase the braking distance.”

Good to Know – Tips for Using Snow Chains

Obligation for snow chains: In most EU countries, there’s no general obligation to use snow chains. However, this obligation is in effect when you see the blue traffic sign of a stylized tire with snow chains. You must then put the chains on the drive axle immediately. Drivers of all-wheel drive vehicles can find the correct axle in the operating instructions.

The snow chain must fit: The chain must fit snugly on the tire and enough space must always be guaranteed in the wheel arches. The choice of the right snow chain depends on tire size and rim width. For narrow wheel arches, fine-link chains are often the best choice.

Round or square chain links: Round links offer advantages in fresh snow and protect the tire on longer journeys. Square chains are better able to claw into snowy and icy pavement. They also have a larger cross-section than round links do, which increases wear volume. Thicker chain links generally withstand wear better than thin ones.

Chain installation: Since each chain has its own way of utilizing tensioning elements, hooks, and fasteners, it’s recommended that you first practice fitting them in dry conditions. If possible in an emergency, install the snow chains in a flat and safe place. It may be necessary to carry out the installation with a high-visibility vest and warning triangle for added security. Gloves and a waterproof mat are helpful.

Tensioning the chain: One to two finger widths of space between tire and chain is fine. The chain travels around the tire while driving and cleans the tread in the process. A chain that is too tight can cause pressure points, and one that is too wide can bang against the wheel housing. Newer chain systems often have an automatic system that retensions the chains. Otherwise, check the fit of the chains again after a short drive.

Driving behavior and assistance systems: Snow chains change a vehicle’s driving and braking behavior, and therefore require an adapted driving style. It’s a desired effect for wheels with snow chains to slip on snow and ice because the chain links grip better. If an electronic stability program (ESP) or traction control system (ASR) counteracts this, it reduces the traction effect. From time to time, you’ll find manufacturers promising ESP- and ASR-compatibility for their snow chains. Otherwise, it’s best to switch off the assistance systems. When driving with snow chains, maximum speed is limited to 50 mph.

Summer tires with snow chains: Snow chains definitely can’t replace winter tires. Combining them with summer tires is therefore a safety risk – the tires with chains on the drive axle have good grip, but almost no grip on the other axle.

Cleaning: Clean the chain after use with lukewarm water and allow to dry. If you want to be thorough, apply a grease spray or chain care product. Store the chains in a dry place.

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