Snow chains and snow socks: rules, sizing and clearance

In short. We found nothing in British law or in the Highway Code that asks you to fit winter tyres or carry snow chains, and the Highway Code's winter rules do not mention either. The rules that bite apply once the car is abroad, and they differ by country. France asks for winter tyres or chains on board from 1 November to 31 March in the mountain communes that its prefects list; the Interior Ministry wrote in February 2026 that the measure is applied without a sanction, while the Foreign Office still warns of fines. Germany has no dates: in winter conditions every wheel needs a winter tyre with the Alpine symbol, and chains are required only where sign 268 stands. Austria runs from 1 November to 15 April, in wintry conditions, and wants winter tyres with at least 4 mm of tread on a radial, or chains on two driven wheels where the road is under snow or ice. Switzerland has no general obligation in the federal texts we read, but its "snow chains compulsory" sign closes the road to a car without metal chains or a device the Federal Roads Office has authorised. To buy the right set, take the full size of the driven tyres, find it on the packet, read the handbook for the axle and the sizes it allows, then measure the gaps around the tyre with the steering on full lock. The tightest SAE class asks for 37 mm in front of the tread and 15 mm beside the inner sidewall. A wheel with a lower offset moves the tyre towards the arch and away from the suspension.

Britain: no requirement found, and the Highway Code is silent

The Highway Code's rules for icy and snowy weather (rules 228 to 231) tell you not to drive unless the journey is essential, to clear every window of snow and ice, and to carry an emergency kit that includes a shovel. They say nothing about chains or winter tyres (GOV.UK, The Highway Code, rules 226 to 237). The Department for Transport answered a parliamentary question on 15 January 2024 by saying that, given how rarely heavy snow and ice occur in the UK, the Government had no plans for a legal requirement to fit winter tyres (written answer UIN 9007). On 3 February 2026 it said that the low frequency of heavy snow and ice, and the known disadvantages of winter tyres in warmer temperatures, did not support a detailed assessment of making winter-rated or all-season tyres standard fitment (written answer UIN 108977). Our guide to winter tyres in the UK covers the home side of this.

So we found no winter-equipment rule for a British car at home. The rules below apply to it on the continent, whatever its plates.

What four countries ask of a car in winter

We read the legal texts and the official pages listed in the sources on 15 October 2026. Rules change and road signs prevail on the day, so check the Foreign Office's page for each country on your route before you leave.

France

The decree that created the "mountain law" winter rule, article D. 314-8 of the road code, applies from 1 November to 31 March in the communes that the prefect of each mountain department lists. For cars and light vans it asks for one of two things: removable anti-skid devices for at least two driven wheels, or winter tyres on at least two wheels of each axle (Légifrance, decree no. 2020-1264). Since 1 November 2024 the decree defines a winter tyre as one that bears the Alpine symbol together with an M+S marking, so a tyre marked M+S alone no longer counts. The road safety authority says the same thing in terms of the 3PMSF symbol, adds that chains or socks must be on board and ready to use, and that signs at the entrance of each zone are what make the measure enforceable (Sécurité routière). The government's English page for visitors gives the same picture and says metal chains suit frequent use and textile socks occasional use (service-public.gouv.fr).

The penalty is unclear, and we say so. The decree sets none. In a reply published on 12 February 2026 the Interior Ministry wrote that, since the start, the measure has been applied with a teaching approach and without a sanction, that a sanction needs a decree, and that none could be published in 2025 (Sénat, question no. 06613). We found no sanction decree published since. The Foreign Office's page for France, for its part, says vehicles in these regions must be fitted with winter tyres or chains and that you could receive a fine (FCDO, France). Some trade pages quote a flat fine; we did not find an official text that sets one. The equipment obligation itself is written into the decree, and it is the thing to plan around.

The "chains compulsory" sign works differently. It means chains must be worn, not merely carried, on snow-covered roads, including outside the winter period. A removable device counts as compulsory equipment under that sign only if it meets articles 9 to 12 of the order of 18 July 1985, and the pack must say so (Légifrance, order of 18 July 1985).

Germany

German law sets no dates. The traffic code allows a motor vehicle to be driven in black ice, slippery snow, slush, ice or frost glaze only if all its wheels carry tyres that meet the equipment rules (StVO, section 2). Those rules define a winter tyre as one that improves snow behaviour and bears the Alpine symbol under UN Regulation 117, with a lower speed index allowed if a label shows the limit in the driver's view (StVZO, section 36). A German motoring magazine dates the end of M+S-only tyres to 1 October 2024 (AUTO BILD, 14 October 2026, in German). The federal fine table sets 60 euros for driving in those conditions without the right tyres, and 80 euros if others are obstructed (BKatV, table 1, no. 5a).

Chains are a different matter. Sign 268 means that the road may be used only with snow chains (StVO, annex 2). Outside that sign, the rules ask only that chains be built and fitted so that they cannot damage the road (StVZO, section 37). The federal texts we read do not say whether textile covers satisfy sign 268; ask the maker of the socks, or use metal chains where that sign stands.

Austria

The Motor Vehicles Act says that from 1 November to 15 April a car or light van may be used in wintry conditions, such as snow, slush or ice, only if all wheels have winter tyres or, where the road is covered by a continuous or almost continuous layer of snow or ice, chains are on at least two driven wheels (KFG, section 102 (8a), version of 15 October 2026). The same section says chains may be used only when needed and fitted so that they cannot damage the road surface. The implementing regulation sets the tread for winter tyres used under this rule at 4 mm on a radial and 5 mm on a cross-ply, and bars a winter tyre from sharing an axle with a tyre that is not one (KDV, section 8).

The transport ministry's English page names the M+S marking as what makes a winter tyre one in law. It gives the fine as 35 euros, with up to 5,000 euros if others are endangered. It adds a point that matters in a claim: after an accident on summer tyres in winter conditions, the driver must show the accident would have happened anyway, or is treated as partly at fault (BMIMI, winter tyres and snow chains).

Switzerland

We found no mention of winter tyres or snow chains in the Swiss road traffic act or in the traffic rules ordinance, in the versions of 1 October 2026; the act asks only that the driver control the vehicle at all times (SVG, article 31, in German). The obligation comes from a sign. The signalling ordinance says that at the "snow chains compulsory" sign (2.48) a multi-track vehicle may use the road only if at least two driven wheels of the same axle carry metal chains; similar devices of another material are allowed if the Federal Roads Office has authorised them. The sign is removed once good tyres are enough, and ends with the end-of-obligation sign (2.57) (SSV, article 29, in German). The Foreign Office advises equipping the car with winter tyres and chains for Alpine winters (FCDO, Switzerland).

Other countries

Other countries, such as Italy, Spain, Andorra and the Nordic countries, may have rules of their own; we have not read their texts, so we write nothing about them here. The Foreign Office page for the country is the first place to look, and the signs on the road are the last word.

Chains or socks: what the sources say

A snow sock is a textile cover that goes over the whole tread; a chain sits on top of it. In 2021 the Swiss Touring Club (TCS) compared conventional chains with textile and rope products, scoring handling, wear and ability on snow (TCS, test 2021, in French).

A tyre maker's UK page adds that on hard-packed snow the two types work about the same, that on fresh snow and black ice chains are more effective and last longer on cleared roads, and that socks are much easier and quicker to fit (Michelin UK, snow chains and snow socks). Where a sign asks for chains, metal chains are the safe choice: that page says only metal chains can be used in Germany and Austria, and the legal texts above name chains without saying whether textile covers count.

The European standard for these devices is EN 16662-1:2020, published in Britain as BS EN 16662-1. BSI describes it as setting safety and performance requirements for supplementary grip devices on tyres of cars and light vehicles, whatever the material (BSI Knowledge, BS EN 16662-1:2020). Austria also has its own standard for snow chains, ÖNORM V 5117, based on EN 16662-1 and referenced in legislation; its catalogue page shows a withdrawal date of 1 January 2027 (Austrian Standards). The standards are paid texts and we did not read them: they are named here only so that you can read the mark on a packet.

Reading your size in five steps

1. Take the full size of the tyres of the driven wheels from the sidewall, for example the figures that our guide to reading a tyre size explains. The wheel diameter alone is not enough: width and sidewall height count too.
2. Find that exact size on the packet. In France the 1985 order asks the packet to list the tyre sizes the device fits, its net weight and its conformity to the order, with a notice in French readable before purchase (Légifrance, order of 18 July 1985, article 11). A pack bought elsewhere may not follow that rule, so check the size yourself. If your size is not listed, the device was not meant for your tyre. Our tyre size calculator compares two sizes; it does not choose for you.
3. Open the handbook at the wheels and tyres section and look for snow chains: which axle, which sizes, which type, what top speed. The TCS notes that the handbook says whether chains go on the front or rear axle.
4. Measure the gaps with the steering on full lock (next section).
5. Try the set on the car at home, on a dry day, before the trip. The TCS advises doing so without a time limit, and Porsche's instructions ask for the same dry run.

On four-wheel drive, the TCS says no rule states which axle takes the chains: the maker's instructions rule, and the ideal is chains on all four wheels.

Clearance: three gaps, and the classes

A chain adds thickness on the tread and on both sidewalls. The gaps that matter are those between the tyre and what surrounds it: the arch, the suspension arms and strut, the brake calipers and pipes.

A chain maker's page recalls the 1980 SAE standard J1232, which has you measure two places: between the tread and the nearest obstacle, and between the inner sidewall and the nearest obstacle (Peerless, limited clearance). The three classes, with their minimum gaps, are in an encyclopaedia entry that gives them in inches and millimetres (Wikipedia, snow chains):

The chain maker adds that most of today's cars need class S products, that car makers often forbid a tyre size because the space is under the class S gap, and that many of those cars can still take its products if you fit them and drive a short distance (its argument as a seller; the handbook comes first). The encyclopaedia entry notes that class S is a common requirement on newer cars, especially with wider, lower-profile or larger tyres or wheels. The SAE standard is a paid text that we did not read: the figures come from those two pages.

In Europe the packet gives a clearance in millimetres instead. One chain maker's datasheet gives a body-to-tyre clearance of 0 mm (EN 16662-1, class 0 to 12 mm) (RUD, datasheet); another is for cars whose requirement does not exceed 12 mm (class 13 mm) (König, CB-12). The figure in a model's name is not a guide on its own; read the datasheet.

How to measure

No source publishes one method, so here is the one their instructions allow.

1. Park on level ground with the steering on full lock, then repeat on the other lock: the gaps change with the steering.
2. At the tightest point, measure three distances: tread to arch or strut cup; inner sidewall to the nearest suspension part, caliper or brake pipe; outer sidewall to the edge of the arch.
3. Repeat with the suspension compressed. Porsche's instructions ask you to check the chained wheel in the extreme (compressed) positions, and Tesla notes that a heavy load reduces the gap between tyres and body.
4. Compare the smallest value with what the notice of the chain or sock asks.
5. Fit the device and drive slowly for a short distance. If you hear contact, a tick or a scrape, stop and take it off. Tesla and the chain maker above give the same instruction.

The table shows how a set of measurements reads against the SAE classes. The four cars are invented, to show the rule: a class is cleared only if both gaps reach its minimum.

What the car makers say

The three texts we read differ, but they reason alike: the clearance is given for a precise combination of car, wheel and tyre.

Two readings. The limit is not the wheel diameter alone: Tesla names a chain for 20 inches on its car, while Porsche clears none for the 20 and 21-inch wheels of the Macan. And Polestar says in so many words that wheels of a size different from the original can rule chains out. The sources are Porsche's instructions, published by the US safety agency, Tesla's handbook and Polestar's handbook; none of them is the edition for a British car, and your own handbook is the one to read. Polestar adds that chains may disturb the pressure monitoring system, which our guide to MOT, TPMS and aftermarket wheels explains.

Large wheels and low offset: what changes

Plus-sizing does not make chains impossible in the sources we read. They say that each combination is cleared or not, and that wider, lower or larger tyres make the tightest class more likely to be needed. What catches is not the number of inches but what comes with it: a width that nears the suspension, a bigger caliper, an arch with less room.

What follows is our own geometry, not a figure from any source. The offset (ET) is the distance from the wheel's mounting face to its centre plane, as our guide to wheel offset sets out. With the same tyre, a lower offset pushes the wheel outwards: more room on the suspension side, less on the arch side. A wider tyre takes space on both sides equally. In round numbers, with the same tyre diameter:

The SAE classes put numbers on two of the gaps only, tread and inner sidewall. The third, between the outer sidewall and the arch, has no figure in what we read: Tesla and Polestar both list the body among the parts a chain can touch, and it is the gap a lower offset can use up. Because the makers clear precise combinations, a wheel with a different width or offset from the original is outside their list: measure the car with those wheels on, and ask the maker of the chains if in doubt. Two cars of the same model on wheels of different width or offset do not have the same gaps, so what holds for another owner's car does not carry over to yours. Real clearance also depends on the shape of the sidewall and on the chain, so treat the table as a way to see the direction of the change, not as a measurement.

Fitting and driving: what the sources say

Our guide to changing a wheel safely covers the ground, the triangle and the jack. For chains, the TCS says not to lift the car.

Wheels from Onyx Forged

We do not publish a chain size or a clearance for your car, and we do not give an offset to pick: a figure only means something for one car, with its brakes, its ride height and its tyres. Onyx Forged is a French brand of made-to-order forged wheels, designed to JWL/VIA standards. The Onyx Forged design office works out the wheel for the car as you described it and checks it with you before anything goes into production; customer service sends you, on request, the width, diameter and offset of each wheel, which are the figures to hold against a chain maker's datasheet. The chain, the car maker's handbook and your fitter come first, and the measure-and-try-on routine above is done on your car with these wheels on. If you plan a second set of wheels for the winter, do the measurement and the dry run with that set, before the trip. See Onyx Forged, the catalogue and how to customise a set.

Frequently asked questions

Do I need snow chains in the UK?

No. We found no British rule that asks for chains or winter tyres, and the Highway Code's winter rules do not mention them. The Department for Transport has said it has no plans to require winter tyres.

Are snow socks accepted instead of chains?

It depends on the country. French authorities name chains and socks side by side. In Switzerland, at the chains sign, a device of another material must be authorised by the Federal Roads Office. The German and Austrian texts we read name chains and do not say whether textile covers count, so ask the maker or use metal chains where a sign asks for chains.

Do I need chains for all four wheels?

No: the French decree, the Austrian act and the Swiss sign all speak of at least two driven wheels. On four-wheel drive the TCS says the maker's instructions rule, and the ideal is all four wheels.

How do I find the size of chains for my car?

Take the full size of the driven tyres from the sidewall, find it on the packet, check the handbook for the axle and sizes it allows, measure the gaps with the steering on full lock, and try the set on at home.

Can I fit chains on 19 or 20-inch wheels?

It depends on the combination. Porsche clears chains on the Macan's 18 and 19-inch rear wheels but none on its 20 and 21-inch wheels; Tesla names a chain for 18, 19 and 20-inch wheels; Polestar does not recommend them above 20 inches. Your handbook is the answer.

What about wheels with a different offset from the original?

The combination is then outside the maker's list. Polestar's handbook says wheels of a size different from the original can rule chains out. Measure the three gaps with those wheels on, with the suspension compressed, then try the set.

How fast can I drive with chains?

Porsche, Polestar and the TCS say no more than 50 km/h (about 31 mph); Tesla says 48 km/h. Follow the notice of the device too.

Can chains go on summer tyres?

The Tesla handbook forbids it and the TCS writes that chains go on winter tyres only. Austria lets a car use chains in place of winter tyres only where the road is under continuous snow or ice. Follow your handbook.

What is the fine in France if I have none?

The decree sets no sanction, and the Interior Ministry wrote on 12 February 2026 that the measure is applied without one. The Foreign Office says you could receive a fine. We did not find a published sanction decree.

Where to go next

For the home side of the question, read winter tyres in the UK: do you need them, and when to fit; for the day the wheels come off the car, how to store tyres and wheels between seasons; for a size that does not fit, what size wheels fit my car. Onyx Forged is a French brand of made-to-order forged wheels, designed to JWL/VIA standards: see Onyx Forged and the catalogue.

Sources

• GOV.UK, The Highway Code, driving in adverse weather conditions (226 to 237).
• UK Parliament, written answers of the Department for Transport: UIN 9007, 15 January 2024 and UIN 108977, 3 February 2026.
• FCDO, foreign travel advice: France and Switzerland.
• Légifrance: decree no. 2020-1264 of 16 October 2020 and order of 18 July 1985 on anti-skid devices (in French).
• Sécurité routière, new winter equipment (in French); service-public.gouv.fr, winter tyres and chains (English page); Sénat, question no. 06613 and the Interior Ministry's reply of 12 February 2026 (in French).
• Germany: StVO section 2, StVO annex 2, StVZO section 36, StVZO section 37 and BKatV annex, all in German; AUTO BILD, 14 October 2026 (in German; our translation).
• Austria: KFG section 102 and KDV section 8 (in German); BMIMI, winter tyres and snow chains; Austrian Standards, ÖNORM V 5117.
• Switzerland: SSV, article 29 and SVG, article 31, on Fedlex (in German; the pages need a browser that runs scripts).
• TCS, 2021 snow chain test (in French); Michelin UK, snow chains and snow socks; BSI Knowledge, BS EN 16662-1:2020.
• Clearance: Peerless, limited clearance, Wikipedia, snow chains, RUD datasheet and König CB-12.
• Car makers: Porsche, Macan (95B) chain instructions, Tesla, Model 3 handbook, Polestar, Polestar 2 handbook.

All pages were read on 15 October 2026.

The Onyx Forged design office.