Winter tires - The basics

[amullo]

I havent seen any thread on the subject, so I figure Ill start one.

Why do you need wintertires anyway?

Well.. The stock “summer”tires that your car is delivered on are optimized for grip and economy for summerdriving. In winter the small thread, low profile and Silica content in the tire is all wrong.
First off the rubber will harden when temps fall. At below 40F/5C the tire is unable to flex as it should, offering less grip.
In the case of Snow, Ice and slush, the tires groves are far to small to offer grip and will foul up quickly. The tire is unable to clean itself. A coarser, more open grove is needed.
In Ice conditions, you may even need steel studs to firmly grip the ice. But studdless wintertires have sipes that over more edge and more control.

So basically, at conditions below 40F with snow and Ice on the road, a winter tire will increase your driving safety.


To start with, here are the basics on what the markings mean

1. The tire needs to be marked with the snowflake.
This indicated that the rubbercompund doesnt stiffen at low temperatures.
2. A winter tire is a tire matrked with M+S on the sidewall - The M+S mark stands for "Mud and Snow". The thread on the tire is course to offer better grip in snow and mud conditions.
3. P for passenger, L for light duty vehicle.
4. Narrow tires offer better grip - The reason being that is a wider tire will float (aquaplane) sooner on both water, snowslush and snow. It will also lessen the surface weight on ice.
5. Higher sidewalls give better grip - The tire needs to be able to flex to let the rubber follow the ground.
6/7 Rims - Alloys are much more common then before for wintertires and this is down to driver choice, but steel rims offer better value for money, but lets face it.. Alloys look great!
8 Load index (numbered) - To coincide with VWs recommendations
9. Speed classification indicates how fast the tire is approved for.


Lets take our car.
A 2.0 TDI GT that came from the factory on 17" rims. Using the stock size of 225/45-17 for wintertires would, givven the rules above, be wrong.

We went with a 195/65-15 combination, which was the smallest rim we could fit because the brakediscs and calipers prevented smaller rims.


OK, so then its time to thionk about what kind of wintertire you need. There are roughly three diffrent types.
1. Studded winter M+S tires with the snowflake mark.
- Generally, these tires are the best for true winterroads and roads often covered in ice, but local laws may prevent their use. The offer unsurpased grip on ice and ice/snow combinations. They offer medium grip in the wet and on dry roads.
EG: Nokian Hakkapelitta 8, Michelin X-ice North

2. Nordic friction M+S tires with the snowflake mark.
- These tires are made for nordic conditions with snow and ice, but not much water. They excel (like their studded cousin) at winterroads that are white with snow or glazed with ice. Grip on dry and wet roads are generally at medium levels.
EG: Nokian Hakkapelitta R, Michelin X-ice, Continental VikingContact5

3. Continetal friction M+S tires with the snowflake mark.
-These tires are made for winters that are wet and slushed, but you still need to go north sometimes. They offer alot more grip then summertires in the wet, snow and ice, but less grip on snow and ice then the above tires. The perfect choice for drivers who generally see snow at the side of the road, but not on it.
EG: Nokian WR, all Pirelli M+S

Then there is the 4:th option.
Friction och M+S tires without the snowflake. Also called "year around" or similar to give them the appearance of being able to cope with all conditions, summer to winter.
These tires are generally pretty bad at everything. They offer low to medium grip in all situations. To be avoided.


- That covers the basics, but Im sure Ive forgotten some stuff that is obvious to me.. Ive been driving on winterroads in Sweden since I was 17, so some stuff I just take for granted.

[Dolmen]

we went for the 16'' rims one size down from standard fare. so far there has only been one day with snowy conditions but the extra wet conditions are still well handled with the cold weather tyres.