Extra Slippy Snow Forecast for this weekend?

This post is also available in: Français (French)

Watch out, if it snows this weekend, the roads may well turn out to be slippier than normal. I’ve experienced this a few times and wondered what was causing the effect. Is it because snow in spring is wetter? Is it the wrong sort of snow? In my opinion it’s neither. It’s probably just because your winter tyres have worn out.

I used to drive 15,000 km over the winter season. I always started off in November with fresh winter tyres and they would see me through the difficult months of December and January just fine. The roads would start to dry up and I’d drive through February and into March without a second thought. The occasional snow storm tends to blow through in March and April, the effects don’t last long down in the valleys but you will still need to be careful when out driving. 15,000km is probably the furthest you’ll manage on a set of snow tires (it could be less than 10,000km). The trouble is they still look fine at this point and are perfectly legal. They will probably have lost all their winter qualities though.

Obviously none of this will mean anything to you unless you actually look at how much tread there is left on your tyres. Something I can’t help doing to any car I see, it’s a leftover from my old job.

Here are some Winter Tyre facts and some opinion too.

  • When living in the Alps winter tyres on a 2WD are generally fine. In fact most of the time they handle better than 4WD cars even on snow.
  • If you have to deal with any hills then you’ll probably need a 4WD. I mean “real hills”, the main roads in the Alps don’t count. But beware. 4WD helps with traction up a hill but it won’t slow you down – in fact 4WD cars can be harder to handle downhill due to their weight. They won’t help you around corners either!
  • Snow tyres have 8mm of depth when new, 4/5mm when used, 1.6mm is the legal requirement. There will be two TWI’s (tread wear indicators), the winter one is not always that obvious.
  • M+S tyres are not a patch on Snowflakes. This might sound like gobbledegook. A winter tyre has a snowflake symbol, an “all year” tyre is often marked as M+S (mud and snow), these are not the same and not a patch on winter tyres. They lack the softer rubber and the sipes (see image below)! You see them frequently on the big 4WD’s from out of town. There is a link to a discussion on this subject here. and one from a manufacturer here.
  • Winter tyres are not good in summer so change them! They are worse than the worst summer tires you can buy. It’s tempting to run them whilst they are legal but it shows a total contempt towards your own safety.

Some people complain about the cost of winter tyres, the hassle of storing them and the fact the whole lot need changing 2x a year. The real running cost of tyres is about 1.5 cents per km winter tyres come out at about 2 cents per km. And remember, whilst you are using the winter tires the summer ones are being saved.

Some general links on the subject here.




The Snowflake and M+S marking are often seen together. If there is no snowflake, then you don’t have a winter tyre.

The treadwear indicators often look like this.

twi 2

But they can look like this. These are easier to spot, when the tyre is worn out then a smooth line appears across the surface.


Here is a picture showing off tyre sipes. It links to lots more.


Why do I think I know what I’m talking about? I took my driving skills gained in the Police in the UK and also 2 seasons of driving transfer vehicles in the Alps to train new drivers for the Tour Operators. I did this for 10 years. I used and fully tested a huge range of vehicles in winter in that time, including all sorts of minibuses, 4WD’s, Land Rovers and company cars.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.