Tire chains are one of the most aggressive and reliable means of regaining vehicle control when roads become slick with ice and snow. They are specifically engineered to provide a mechanical advantage that rubber tires cannot achieve on frozen surfaces. For drivers navigating mountainous regions or areas with severe winter weather, understanding this mechanism is necessary for safe travel. This article clarifies how chains improve traction on ice and outlines the requirements for their correct use.
How Tire Chains Achieve Traction on Ice
Tire chains are effective on icy surfaces because they operate on the principle of high-pressure penetration rather than relying on friction alone. When chains are fitted, the vehicle’s weight is concentrated onto the small surface area of the metal links contacting the road. This focused pressure allows the metal to exert a force strong enough to break through the slick layer of water that forms on top of ice.
This thin film of water, created by the tire’s pressure and friction, causes standard rubber tires to hydroplane. The metal links act like miniature cleats, piercing this water layer to physically bite into the solid ice structure or the road surface underneath. This mechanical interlocking prevents the tire from slipping, providing the necessary grip for starting, steering, and stopping.
Types of Traction Devices and Their Performance
The market offers several types of traction aids, with performance varying significantly, particularly on pure ice. Traditional link-style chains, typically made of heavy-duty steel, provide the most aggressive mechanical grip and superior durability for extreme conditions. They are the most challenging to install and create the roughest ride due to their robust construction.
Cable-style chains, often called snow cables, use steel aircraft cable instead of thick links, offering a lighter, less bulky design. These devices are generally easier to install and produce a smoother ride, making them a popular choice for vehicles with limited wheel well clearance. While they offer good traction, their lighter construction provides less aggressive penetration on thick ice compared to traditional chains and they are less durable overall.
A third option includes textile traction devices, commonly known as snow socks, which slip over the tire like a fabric sleeve. These are the easiest to install and are approved as a legal alternative in many jurisdictions where chains are required. Although they perform well on snow by enhancing friction and absorbing water, independent testing shows they offer significantly less braking and acceleration traction on sheer ice compared to metal chains or cables.
Rules for Installation and Road Use
Proper installation of any traction device directly impacts safety and performance. Chains must be installed on the vehicle’s drive wheels: the front axle for front-wheel drive, the rear axle for rear-wheel drive, or all four tires for four-wheel-drive vehicles, depending on the manufacturer’s recommendation. The chains must be fitted snugly and centered on the tire tread, with the hooks facing away from the sidewall to prevent tire damage.
Once installed, drivers must drive a short distance, typically 50 to 100 feet, and then stop to re-check and re-tension the chains. This ensures the chains have settled properly and are tight enough to prevent them from loosening and damaging the vehicle. Chains impose strict driving limitations, with maximum speeds generally restricted to 25 to 30 miles per hour to avoid centrifugal forces from causing them to break or fly off.
In many regions, chain control laws dictate when and where chains are required, often signified by road signs. Drivers must carry and install chains in these mandatory zones, but operating a vehicle with chains on bare pavement is illegal. Driving on clear roads causes rapid wear to the chains and can severely damage the road surface, necessitating immediate removal in a safe pull-off area once conditions improve.