When do I need to mount Winter tires on Car

Transportation, Travel and Trips
21
Sorry, this last line is complete rubbish.

Even in braking, a 4x4 has significantly more braking power because:

- engine braking works on all four wheels, so you are better off even before you hit the brake pedal

- having the engine provide power to the wheels allows anti-lock brakes to work on much slippier surfaces

Anyone who has driven a two-wheel drive car on ice or hard snow knows this - the non-driven wheels will lock fairly easily, even with good anti-lock brakes keeping the others from sliding.

22
Consumer Reports disagrees with you:

https://www.consumerreports.org/cro/...snow/index.htm

23
Not if it's an automatic.

Tom

24
I'm speaking from my own experience - my current FWD will lock the back wheels on packed snow, but not the front. 4x4 I've driven don't lock either.

The test isn't anyway what I was talking about - you don't measure stopping distance on hard packed Swiss mountain snow by braking from 60mph; you stop quite nicely by hitting the barriers or the bottom of the valley at that speed!

They also tested two completely different vehicles instead of FWD / 4x4 variants of the same one, which seems pretty silly.

25
Depends on the type of automatic - it does on some of the new electronic/clutch based ones.

And on really slippy snow, you can anyway put it into a low gear manually to get engine braking / avoid unwanted changes that can break your grip.

26
Even a Subaru can get stuck: https://jalopnik.com/who-says-you-ne...age-1688221525

Recommend the following before you big trip:

1. Mount Winter tires

2. Pack a bag of sand

3. Pack a shovel

27
Your rears are locking first because they have less weight on them. Ideally all 4 should lock at the same time. The fronts do 60% of the braking, they always do, regardless of how many wheels are driven. Modern cars (i.e. ABS) usually manage to get all 4 corners to lock more or less equally, but not necessarily simultaneously, but it is an incredibly complex dynamic scenario to address. In a sense, ABS systems react to the grip on the surface of the bit of road you just finished sliding over. Most ABSs cut in too early for my taste.

Under braking it really doesn't matter how many wheels are driven - there are very small differences because of the inertia of driveshafts/diffs, but these are all minor, and don't play a role once you've stabbed at the binders and exceeded 10% slip/grip.

Under engine braking, yes, with AWD you can distribute the retarding effort over twice the surface area compared to 2WD... but even that depends on how the AWD system is arranged.

But the main thing is never go over 10% slip/grip.

(and yes, few car tests compare like for like)

28
then you better have a light Panda 4x4 than a 2500 kg SUV

29
Depends... Putting tires that are too wide on any car can mess you up by increasing the contact area - basically the tires just don't manage to push the snow out of the way.

But generally, the less weight you're moving the easier it is to retard. The biggest single factor in any edge case isn't the retarding force at the tires, it's the retard at the wheel or pedals.

That's why I keep saying that people should take a skid school/high perf/winter driving course. Winter highway traffic at speed (round about Horgen for example) is the wrong place to try to learn how to reconcile Newtonian physics and insurance premiums - there's way too much going on to get a learning effect. On a course you get a much better learning effect - even if you only learn half of what they're teaching.

30
...this thread begins to remind me of traffic on the first day of Winter's Surprise, and the changes of conditions in even slightly different elevations. There are priorities. Your tires are your only connection with mother earth, so if they aren't appropriate for conditions, even your electronic Mommy's with their false senses of security won't save you. Then comes your vehicle and then your skill at handling it.

Temps are already approaching zero in places. Get appropriate tires at a reasonable date and get on with it.

31
True, just apply some common sense and don ́t forget that your insurance may baulk if you have inappropriate tires and something happens.

32
...and if something happens or any cop stop, your friendly coppers will definitely check your tires, including expiry date, any season, any weather, any time.

33
There is no "expiry date"

Tom

34
We have one of each!

(though I think that the Maverick weighs less than 2500kg)

Tom

35
Hi Jamboree

Not sure if there's a date in Switzerland, as it really depends on the temperature and snow onset. The general recommendation is to have snow tires on when the temperature is less than or equal to 5 deg C.

Rgds

Mav

36
Geezus! You call my post rubbish and counter argues with something completely wrong.

First of all, engine braking power is a FRACTION of that of the brakes themselves. Engine braking is useful when you are going downhill and very light on the brakes. As soon as you need to brake hard, engine braking becomes almost irrelevant. Second, the front wheels are responsible 70-80% of all stopping power, so even if it's an AWD, engine braking has a minor effect.

37
so what you can best do is:

- mount winter tires

- underinflate the tires for more grip (best is to kick the tires before starting the car - just to be sure)

- mount snow chains as of December (on all 4 wheels + spare wheel) so that you will never be surprised

- as brakes and grip are most effective on the front side of the car, driving your RWD car in reverse gear all winter long

- put a snow shovel in the car

- lots of sand, also because more weight gives you more grip

- let the engine run all winter long as the car works best when the engine is warm and with no frozen windows

38
They do.

If you tyre says for example 20.15 there's a valid period set by the manufacturer (for car tyres almost always 4 years), so they expire at week 20 of 2019.

Nothing which is legally enforced, and it is also allowed to sell tyres without manufacturing week mentioned.

But worth looking into when buying tyres, especially with the not so common sizes which are in stock it's not impossible to buy tyres which have been manufactured already 4 years ago. I myself would not agree on buying those, since you are buying tyres of which the manufacturer says they are not valid anymore and you still want to drive them some years.

In theory you could get in problems with your insurance if one of your tyres blows up and it expired already years ago, I myself still believe it depends more on the actual state of the tyre on not only on the date.

39
That is the manufaturing date.

Tires, at least from a legal point of view, have no expiry date.

You will pass MFK no problem with tires 10 years past their date of manufacture, even 20 or 30 or more.

Tom

40
In Switzerland it is not mandatory to have winter tyres at all. BUT as a few mentioned, if you have an accident of sorts in winter with summer tyres, your insurance will likely not cover any damage.

Rule of thumb/rough recommendation is to drive with winter tyres from around October to around Easter (give or take)

Here's the rules for some of your other countries:

https://www.reifendirekt.ch/Winterreifenpflicht.html

- Slovenia: mandatory between 15 November and 15 March

- Austria: mandatory between 1 November and 15 April if "wintery conditions"

- Germany: mandatory in "wintery conditions"

So best to just put on winter tyres in October before you go on your trip(s).