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Tire Chains, Explained

After reading, you'll understand what SAE Class S really measures, why cross member pattern changes how a car behaves, and how to check whether a device is legal where you drive.

Updated August 23, 2026 · Companion to our Automotive review

In this guide

Almost every tire chain mistake is a fitment mistake. People buy by tire size alone, discover the set will not clear the strut, and either force it or drive off with something rubbing. The vocabulary that prevents this is small but non-obvious, and most of it lives in a single SAE clearance standard plus your owner's manual. The rest is about how a device tensions itself and how the steel is laid out across the tread.

The 30-second version

  • Clearance class beats brand, because a device that needs more room than your wheel well has cannot be made to work.
  • Your owner's manual is the authority, and it can prohibit traction devices entirely on certain wheel and tire combinations.
  • Pattern decides more than traction, since continuous cross members help with steering and braking, not just getting moving.
  • Tensioning is where people fail, so a self-tightening or built-in-tensioner design is worth paying for.
  • Legality is product-specific, and agencies publish approved device lists by name, sometimes even by drive layout.

The products this guide is about

Our verdict on each, with the full reasoning on the companion review.

What actually matters

  • SAE clearance class - This is the standard that says how much space a traction device may occupy around the tire. Class S is the tight envelope most modern cars require; Class U is the roomier spec for vehicles with unrestricted wheel wells.
  • Inside sidewall space - The measurement from the inside sidewall to the nearest obstruction is usually the binding constraint, not the tread face. Peerless publishes 0.59 in (15 mm) for its Class S link products and 6.3 mm for the Super Z6.
  • Cross member pattern - Ladder, diagonal and diamond describe how the steel crosses the tread. Ladder gives grip in rungs with gaps between; diagonal and diamond keep something under the contact patch at all times.
  • Tensioning system - Chains must stay tight or they flail and damage the car. Some designs ratchet themselves tight, some include rubber tensioners, and some require you to buy tensioners and re-tension by hand.
  • Fitment method - Devices that fasten from outside the wheel and do not require moving or jacking the vehicle are dramatically easier to fit on a cold shoulder in the dark.
  • Device type - Link chains, cable chains and textile covers behave differently on traction, ride quality, weight and lifespan, and they are regulated differently in some jurisdictions.
  • Legal approval - Chain control rules vary by state and province, and alternative traction devices are typically approved by product name rather than as a category, so the specific model matters.

The specs, in plain English

SAE Class SThe Society of Automotive Engineers definition of the least space that should be available around the drive tires for a winter traction product on a limited-clearance vehicle. Peerless publishes the Class S link chain envelope as 1.46 in (37 mm) at the tread face and 0.59 in (15 mm) at the inside sidewall. Most modern cars need a Class S product.
SAE Class UThe clearance spec for regular tire chains on vehicles with unrestricted wheel well room. Peerless lists its Class U style profile at 1.97 in (50 mm) at the tread face and 0.91 in (23 mm) at the sidewall. Fitting a Class U chain to a car that only has Class S room is how brake lines and fender liners get damaged.
SAE J1232The SAE document Peerless cites for these clearance definitions. It specifies that the minimum clearances must be maintained around fenders, braces, suspension parts, strut housings, splash pans and fuel and brake lines. It is the reason clearance is quoted as two numbers rather than one.
EN 16662-1:2020 and Ö-Norm V5117The European standards that make a device legal winter equipment, and the ones most non-US chains are certified to. They are dynamic tests: König notes they require a device to lift no more than 25 mm at 50 km/h. European makers also quote a millimetre figure in the model name, such as the 12 in CB-12, which König defines as the chain's static footprint, how much space its thickness occupies in the sensitive areas of the wheel. None of this is an SAE class, so a European certification is not a US clearance rating.
Cross memberThe part of the device that actually crosses the tread and contacts the road. On a link chain it is steel links; on a cable chain it is a cable wrapped in alloy traction coils. Cross member material and shape drive both grip and how long the set lasts.
Ladder patternCross members running straight across the tread like rungs, with bare tire in between. It is the simplest and cheapest layout, and it works for pulling away in a straight line. Grip comes and goes as the rungs rotate through the contact patch, which shows up in steering and braking.
Diagonal patternCross members set at an angle so something is always under the contact patch. It gives steadier grip and a smoother ride than a ladder for the same amount of steel. The Super Z6 and the Z-Chain both use this layout.
Diamond patternCross members that interlock into a diamond or lattice, which keeps continuous coverage across the tread and resists the chain shifting sideways. It generally gives the best all-round behaviour on a passenger car. The Auto-Trac uses an alloy diamond pattern link.
TensionerA rubber spider or built-in mechanism that keeps a chain snug on the tire after fitting. Some products require them and sell them separately, some include them, and some are designed so that adding one is actively discouraged. Loose chains are the main cause of body and brake line damage.
Alternative traction deviceThe regulatory term for something other than a metal chain that a jurisdiction will accept when chains are required, such as a textile sock or a mesh device. Approval is granted product by product. Washington State Patrol, for example, publishes a chart listing each approved device and which drive layouts it covers.

Green flags vs red flags

Green flags

  • The manufacturer states an SAE class explicitly, and publishes the clearance numbers behind it rather than just a badge.
  • The listing gives an exact tire size range, and the maker offers a fitment lookup keyed to your tire size rather than your vehicle.
  • Tensioning is handled by the product itself, either a self-tightening ratchet or tensioners that ship in the box.
  • The device fastens from outside the wheel and does not require jacking the vehicle or reaching behind the tire.
  • The product appears by name on a state or provincial approved device list if you plan to rely on it in a chain-control area.

Red flags

  • The listing names a vehicle rather than a tire size, since two trims of the same car can take completely different sizes.
  • The clearance claim is vague, for example low profile or fits most cars, with no SAE class and no measurement.
  • Tensioners are shown in the product photos but described as sold separately in the fine print.
  • A textile or mesh device is marketed as legal everywhere chains are required, without a link to the agency list that says so.
  • There is no stated speed limit or wear indicator, which suggests the maker has not tested the product to a recognised standard.

Who's who: the brands

  • Peerless - A long-standing American chain manufacturer whose passenger range spans budget ladder chains through the self-tightening Auto-Trac. It also owns Security Chain Company, so two of the names in a US store are one manufacturer.
  • Security Chain Company - The Peerless traction brand behind the Z family, including the Super Z6 built for vehicles with almost no sidewall clearance.
  • AutoSock - The Norwegian company that invented the textile snow sock and carries the widest set of formal certifications in that category.
  • König - An Italian chain maker sold in North America under both the König and Thule names, which publishes a clearance figure and an EN 16662-1 certification for every model, from the manual-tensioning CB-12 up to the self-tensioning XG-12 Pro and the external K-Summit.
  • pewag - An Austrian manufacturer whose passenger chains, such as the Servo 9, are built around self-tensioning systems and rim protection.

How to read a listing without getting fooled

Work through a listing in this order. Start with the tire size printed on your sidewall, not the vehicle name, and confirm the product covers that exact size. Then find the SAE class and, if the maker publishes them, the two clearance numbers behind it, because that is what tells you whether it will physically fit. Next look at how the device tensions and whether tensioners are included, since that line is where budget chains hide a required extra purchase. Check the cross member pattern to understand how the car will behave with them on. Confirm the stated speed limit and any wear indicator. Finally, if you are buying to satisfy a posted chain requirement, search for the product by name on the relevant transport agency or state patrol list before you rely on it.

How much should you spend?

Budget sets are ladder-pattern cable chains, basic twist-link chains and entry-level European link chains. They will get a car moving on packed snow, but the budget line is where tensioning gets left out: some expect you to buy rubber tensioners separately, and others, such as the König CB-12, expect you to stop after a few dozen metres and tighten by hand. Compare the working cost and the roadside effort, not the shelf cost. The mid-range covers the products most people should be looking at: cable chains with built-in tensioners and low clearance requirements, and certified textile covers. Premium buys you alloy link chains with self-tightening mechanisms, diamond patterns, and European self-tensioning designs with rim protection. The jump from budget to mid-range buys convenience and safety margin and is usually worth it; the jump to premium mostly buys durability and is worth it if you fit chains more than a few times a season.

Questions, answered

Can I leave chains on once the road clears?

No, and this is the fastest way to destroy a set. Cross members and textile fabric are designed to work against snow and ice, not asphalt, and bare pavement wears them out in a very short distance. Peerless advises not exceeding 30 mph with any traction product, which is also a hint that these are not for clear roads. Pull off safely and remove them once you are past the snow.

Do I need chains on all four wheels?

Usually you fit them to the drive wheels, and AutoSock's instructions say the same. Some jurisdictions require more in specific conditions, and vehicles towing trailers can be required to have a set on a trailer axle as well. California publishes a placement diagram covering all vehicle types alongside its chain control levels. Follow the posted requirement and your manual rather than a general rule.

How long should a set last?

It depends far more on how you drive than on how much you paid. Link chains used only on snow can last many seasons; the same chains run on bare pavement can be worn out in one trip. Textile socks are explicitly consumable, and Washington State Patrol's chart says to replace an AutoSock once half of it shows black yarn. Avoiding wheelspin and avoiding clear road are the two habits that extend life.

Is it worth practising before winter?

Yes, and it also doubles as your fitment check. Peerless recommends pre-fitting any traction device and driving a short distance, stopping immediately if you hear a ticking sound that indicates contact. Doing this in a dry driveway tells you both that the device clears your suspension and that you know the sequence. Fitting a set for the first time on a snowy shoulder at night is where people get hurt.

Ready to choose? See our top pick, the alternatives, and the one we'd skip See the Tire Chains verdicts

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