When to put snow chains on

A snowHead

Hi everyone, I am confused (again).

I am in resort (La Tania), I have a four wheel drive car with winter tyres and a set of snow chains. It is forecast to snow on my drive back to the airport.

When and in what circumstances would you advise I fit chains? Obviously I would rather not fit them if possible, but I realise they are worth fitting sooner rather than later.

Also hire company only provided two chains, do I need four?

A snowHead

You should fit chains either when the gendarmes tell you to, or at the first hint of loss of traction - whichever comes first. But with winter tyres and 4WD you probably won't need them.

If you're not confident that you can fit the chains quickly should you need to, have a practice.

Well, the person's real but it's just a made up name, see?

The simple answer is 'before you really need them'

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4WD won't help you stop. What sort of car is it? You can wreck a centre diff if you have two with chains on and two spinning on some cars. (Generally the ones which started life modelled on a rally car.)

Anyway, snowHeads is much more fun if you do.

If its so bad you need chains you have two sets to put on the axle with the highest % of the drive. Most 4x4 are 60/40 just Google the car model for the info for that car.
IFIRC LaTania is quite low and unless you are leaving in the middle of the night the snowploughs will be out and if driven carefully and braking sensibly you probably won't need the chains.

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With winter tyres and 4x4 i'd be amazed if you needed chains particularly going down the mountain. Saturdays the gendarmes are more picky.

I've been up and down to our apartment in val thorens hundreds of times and through much of a couple of winters and have only had to use chains on a bare handful of occasions. That's with a standard front wheel drive car and winter tyres. Few people in resort bother with 4x4s. I rarely/never drive on saturdays though.

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Apologies didn't real the full question.

La Tania, going down the mountain on winter tyres, you'll be fine without chains.

After all it is free

@craigjbarker, can you check and report what tyre model you have on your car? The only place you would need chains is on mountain roads. down in the valley winter tyres and 4wd will not require chains (on the contrary, they are dangerious on slush etc. Chains would not also help in braking situations if you have proper winter tyres (the only advantage chains have in getting grip in deep snow situations going uphill).

In an unlikely event you would need to put chains on 4wd, check car's manual and follow instructions there. There will be instructions which axle chains should go on and whether you need to disengage some of the drive aids by pressing some of the buttons - this will be car specific, a random advice on online forums can make damage

Thanks for advise.

I have a BMW 2 series x drive.

I will have a look in manual to see what it says.

Nice to know I should be ok without them. Have fitted them on a car with summer tyres before to go over Montgenevre from Serre Che. Made sure I got a car with winter tyres this time.

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@mooney058, would you care to explain why chains are dangerous in slush and do not help with braking. The only time I have come near to putting chains on my car fitted with studded tyres is when it is slushy. Before the studded tyres I certainly found chains are beneficial when braking on ice and packed snow even with winter tyres fitted.

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Like you, I am in the Alps with my 2 Series and winter tyres, although only 2WD, and my chains in the boot. As mentioned, you're very unlikely to need chains in your xDrive with winter tyres, unless you hit a steep incline or solid ice or are directed by the police.

BUT: Check your manual and it is likely to recommend that you disable DSC (Dynamic Stability Control) and enable DTC (Dynamic Traction Control) by pressing the 'car-with wobbly-lines' button by your shift stick. You'll see TRACTION come up on the instrument display. This makes sure that the traction control behaves correctly for snow or chains. The manual is poorly translated but essentially the default for a 2 series is that DSC intervenes to stop you spinning if you put too much power to the driven wheels. But in snow, or with chains fitted, you want the system to give priority to traction. You leave it in this setting until you're back on tarmac.

I've written a Guide to Winter Tyres and Chains for 2 series Owners - see http://www.babybmw.net/howtos/Winter%20Wheels%20Guide%202%20Series%20v2.pdf

You know it makes sense.

The chains will usually go on the wheels with the drive bias, on an xDrive. That's normally the rears. Check your manual.

Otherwise you'll just go on seeing the one name:

@mooney058, If the tyres can reach tarmac then I agree chains are not a good idea. Very often the road surface under slush wil be ice, when there is slush 10 cm or so deep winter tyres behave just as they do in deep fresh snow and can't generate enough grip to push the slush / snow out of the way.
Chains on studded tyres, no I'm not joking, studded tyres are only significantly better than winter tyres on hard pack and ice, it's certainly not an everyday thing but there are chains in my boot for that once/ twice a season emergency.
Your last paragraph is spot on, living as I do on the side of a mountain with a 17% gradient road with a hairpin half way down it is necessary to fit chains to get down in icy conditions (not with my studded tyres),yes you have to go slowly. A couple of times a season someone goes of the side of the road many in 4x4s because they have no grip going downhill. The cars that do have trouble never have chains.
Maybe living where I do my views / experiences of this sort of thing may be considered extreme but I only ever advise based on these experiences. On the odd times when the road to resort has been made mandatory for chains ( 4 times this season ) there are far more problems there than on our little mountain road used mainly by locals.

A snowHead

I hesitate to try to contribute to such a contentious topic, but...

There are some roads in BC where carrying chains is mandatory. These are, to my knowledge, not public highways, but access roads to ski areas here and there. I don't know why they have those rules, but I suspect it's as above: sometimes you're going to need them. You mostly don't get tourists in those places.

Unless you're going to those roads, you don't need chains in BC. I don't know anyone who has them. Even if you do go to those places, a lot of the time you won't get you into trouble. It will increase your risk.

I think the second post answers the original question.

In BC they have "chain up areas", but those are for trucks, for whom chains are mandatory on the highway. Driving an ordinary car I stay away from those places, which often aren't ploughed and look like traps to me. => those are not a cue that non-truck drivers need to "chain up".

Ordinary cars are good with M&S or better tyres, there's no legal or practical need for chains on mountain roads (eg the Coquihalla, Duffy Lake Road). I've never had to chain up on any major BC highway. I've never had to use chains on logging access roads with 50cm fresh on them either. I can of course easily imagine nasty enough conditions to warrant the use of chains, but I'm not sure I'd be attempting to cover much ground in those extremely rare circumstances, and if I did I'd likely be behind the plough.

I believe that some modern "chains" are more tolerant of mixed ground than the traditional metal jobs.

A snowHead

For once, @philwig, I have to completely disagree. IMHO... wink

Unless N.A. definitions are quite different,

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If you were supplied M&S tyres off a car hire company which you had paid extra for winter tyres, would you have a valid argument with them that they have not supplied winter tyres?

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I believe that a 4x4 should be shod with 4 sets of chains. IMHO it would be incredibly rare to bother to fit chains on a proper 4x4 assuming the driver is competent.

Anyway, snowHeads is much more fun if you do.

@craigjbarker, In Switzerland, yes. They are not "winter" tyres. You need the "three-peak-mountain with snowflake ('3PMSF')" symbol. That said, some M&S tyres are also 3PMSF...

c.f. http://www.goodyear.eu/corporate_emea/our-responsibilities/road-safety/winter-tire-recognition.jsp although Goodyear confusingly suggest that "true" winter tyres do have both...

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In France ( La Tania ). The law says that you must you chains / approved socks where the blue B26 sign is active, un you must remove them where the B44 sign is displayed.
Sometimes there is a light on the sign to show that it is force, otherwise it says "En Cas de Neige", which means it is in force whenever there is snow.
Sometimes you might also see "Pneus Neiges admis" which means that if you have snow tyres then you do not need chains so long as :
1: The 2 tyres on each axle are the same
2: The tyres on the driven axle carry the 3PMSF logo

Then you can post your own questions or snow reports...

Thanks for the info learning loads.

After all it is free · Last edited by After all it is free on Thu 2-02-17 17:40; edited 1 time in total

@Charliee: There can be some confusion regarding chains on 4x4s, vs Sport SUVs vs AWD cars like the Audi Quattro and BMW xDrive. The OP has what's basically a road car with a biased AWD system specific to BMW (xDrive), not a 4x4 in the commonly-applied sense. As mentioned, not all 4WD/AWD are the same - what applies to one type of technology, and on a specific range/model does not necessarily apply to all. I also have seen 4x4s locally in the alps with chains all-'round, but the manufacturer's recommendation for xDrive on the 2 Series is, specifically, to put chains only on the rear wheels, and not all four.

The only time I've had to put chains on my various winter tyre cars is when I've had to pick someone up in our ski party who has arrived by train separately, in the evening, down in the valley. Where we stay, the snow-clearing is done first thing in the morning, so if it snows heavily during the day, it can accumulate. The drive out of our apartment block is steep and has a hairpin at the end, so although we nearly make it up on winters, I just had to concede defeat and put chains on. I've driven over the Jura mountains a number of times in deep snow in a AWD and winters, with some locals in the ditch, and had no problems. Last time I did this was in my BMW 330d Touring xDrive 2 years ago.

Frankly, the most terrifying winter journey I've done was in Jan 2015 going 'round Lake Geneva. It was very slushy and this was piling-up between the autoroute lanes. Every time a car changed lanes it would wobble dramatically. No one seemed to be going any slower than usual - we opted to come off and go over the Jura in the snow and this proved much less dangerous!

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Just to clarify: There is no official definition or certification of 'mud+snow' tyres, or 'all season' tyres. The 3PMSF in contrast is an official definition and certification of the term 'winter tyre' relating to various features and compound chemistry. This causes a lot of confusion.

If you get a winter tyre in the EU, it should come with a 'mountain and snowflake' symbol on the side to verify it's a 3PMSF. It'll have a different compound chemistry to a summer tyre; a more obviously 'chunky' tread pattern; and lots more sipes (little grooves) than a summer. Overall, the compound will give better adhesion as temperatures drop below 7C; the larger tread pattern will be less prone to aquaplaning in the wet and standing water; and the sipe and tread design will trap snow so as to give improved snow-on-snow traction (but without accumulating so much snow on the tread that it's useless). So it's a good thing to have if it's cold and wet, even if it's not snowing.

In most EU countries, an M+S tyre is not regarded (rightly) as a winter tyre. There are a very few tyres that are both (Winter and M+S), but most UK M&S tyres are absolutely not winters.

'All season' is more confusing, because these are more likely to also be Winter Tyres (3PMSF) as well - especially from well-known manufacturers. However, I still wouldn't recommend All Seasons that are also Winters, as they are still not as good as winters in winter or summers in summer. Trouble is, there's no clarity on how much they are compromised. But I can see their attraction if you are in a marginal climate where it's fairly mild but you do get the odd winter snow each year.

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See that word "snow" and "chain"...

Fit the chain when there is snow.

You know it makes sense.

Otherwise you'll just go on seeing the one name:

A snowHead

Had a look in the Disco's handbook and that says chains on front

A snowHead

Well, the person's real but it's just a made up name, see?

http://www.bbc.co.uk/news/uk-scotland-highlands-islands-38853227

Drive one of these and you wont need to !

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Anyway, snowHeads is much more fun if you do.

If you have AWD and 4 snow tyres, then you should be fine in most conditions. If the conditions become extreme, then the authorities will close the roads anyway. After 7 seasons in the mountains, the rule is to stay indoors if there is more than a foot of snow on the roads. I have had an Audi allroad and now a Subaru Laegacy Outback. Never had chains. If they can't do it , then walk or ski.

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I have both chains and snow tyres and in several seasons round europe I have never needed the chains on a front drive car

Then you can post your own questions or snow reports...

Just a note relating to the title: I can't stress enough how important it is to try fitting your chains before you need to use them in anger.

I was ill before our current Alpine trip so I didn't have time to do this with our new chains. Fortunately, before I had to use them today, I was able to test-fit them in a warm and well-lit underground garage. It became apparent that the chains I have generally need/benefit from some pre-adjustment of the links to be the right circumference for the majority of tyres they are designed to fit. It took about an hour to adjust the links on both chains to be the right circumference.

It looks like my chains 'out the box' are at their minimum circumference. They should fit a variety of tyre sizes but out the box, you probably need to extend the links if you want them to fit or fit optimally. They may be 'self adjusting' - but this is only within certain limits.

On re-reading, I could see that the Owner's Manual wasn't recommending 'fit them first' as a general piece of advice - it had specific instructions for resetting the links to extend the chain length because you are quite likely to need to do this.

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When to put snow chains on

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