road conditions, such as surface material, (rock, gravel, asphalt, cement), weather conditions, (temperature, wet conditions, dry conditions), tire conditions, (tread design, tread depth), tire inflation, tire composition, (softness of rubber) vehicle weight and speed, tire movement other than rotation, (straight line or turning). and probably a dozen other things..
To grip the road surface. You need tread especially in wet conditions.
It varies largely depending on your driving patterns, You should replace your tires when the tread depth gets to 2/32" if you only drive in a dry climate. If you drive in lots of wet weather and snow then replace them when they get to 3/32". Place a penny in the tire tread with Lincoln's head down. If you can see the top of his head you are at 2/32" and they for sure need replacing.
I doubt that very much.
A worn tire reduces friction and tracktion, this could be dangerous in bad weather conditions., A2 A worn tyre would actually improve friction in dry conditions, because the surface area touching the road, will be greater without tread. This why racing cars use 'slicks' in dry conditions. The problems arise in wet weather. The thinnest film of water between the tyre and the road, will cause a sudden decrease in friction, 'aquaplaning'. The tread is there purely for wet conditions.
Tires should be replaced when the tread wear reaches the level at which your state no longer considers them safe usually 2/32" or when they begin to show signs of irregular tread wear or weather cracking.
Those tires aren't save for winter driving in Wisconsin because the tread is warn.
It is a tire with a less aggressive tread since there is no snow or ice to worry about and a smoother ride and a longer lasting rubber compuond. They will also have good wet weather driving characteristics.
Tires usually come with a very sticky tire tread, an all weather tread type, or a winter performance tread type.
the tyres could blow and you may lose controle of your car
The right time in winter to have a winter tire is dependent and dictated by the weather conditions in one's area. When the weather begins to change to snow and the roads become colder, tires will benefit from the boost of more additional traction and tread.
If your tires do not have enough tread left then they can skid easily because there are no edges of a tread to grip the road surface. It's the edges of the tread that actually grabs the road the best and not the flat rubber. If you have good tread then perhaps your car is over powered for the tires that you have. Check with your vehicles manufacturer as to the recommended tires. The best thing would be to talk to a tire shop. They could give you the best information.