Ever since the introduction of the all-season tire, drivers have slid and spun through the coldest months of the year. Here�s the kicker: it doesn�t seem to matter whether there�s snow on the ground or not. Unlike all-season tires, severe-condition Winter tires (identified by mountain and snowflake symbols on their sides) have tread patterns and rubber that are tailored for colder conditions. And that helps them perform better than all-season tires once temperatures plummet, whether or not they have to dig through the white stuff.
Below we have outlined some of the most common winter tire questions we receive. If you would like additional winter tire information please contact us at 866-9 BMW-PARTS.
How will I know which tires are winter tires?
Start by speaking to one of the experts at BMW (866) 9-BMW-PARTS. Winter tires bear the "mountain snowflake" symbol on the sidewall of the tire, which tells you that this tire has been tested and passes winter safety standards. To qualify for the severe snow usage symbol, winter tires must perform a minimum of 110% better than a standard tire in a mandated snow traction test; however, many winter tires are 130-150% better, which translates to shorter stopping distance and better handling.
What is the difference between all-season tires and winter tires?
All-season tires do not have cold weather rubber compounds, channeling tread patterns, the large number of tread sipes (tiny slits in the tread blocks) for wet surface control, and the open tread block pattern for deep snow traction that winter tires feature. The lack of a formal "snow" designation on the tire has further fuelled the misconception that "all-season" tires also mean "winter" tires.
It's winter, but I don't see snow on the ground yet. Is there still a benefit to using winter tires when there is no snow?
On dry pavement, the overall performance of an all-season tire steadily declines as the temperature gets colder. The crossover point is about 41 degrees Fahrenheit. Colder than that, a winter tire outperforms an all-season tire. Winter tire performance sharply improves as temperatures fall from 41 degrees to -30 degrees Fahrenheit, while the all-season tire approaches the "not recommended" status.
How does the tread design of winter tires affect their performance over all-season tires?
Winter tires typically feature a unidirectional tread design. The unidirectional, V-groove tires move slush and water out of the way better than any other tread design. The more open the tread design, the better the tire will perform against accumulated snow. The larger the tread blocks, the better the handling, steering response, and transient response. The more sipes (tiny slits in the tread blocks), the better the tire will work on wet pavement, which is different than anti-hydroplaning. New advances, such as Goodyear's patented 3D-BIS - which stands for three dimensional block interlocking system - causes tread blocks to actually interlock during cornering, stopping, and at increased speeds.
Only two of my tires need replacing at this time. Should I replace just the two?
To help maintain control and stability of your vehicle in slippery conditions, we recommends that snow tires are installed in sets of four. Vehicle handling will be improved when identical tires are installed on all four wheels. Also, mixing tires with different tread patterns, internal construction, and size degrades the stability of the vehicle and should be avoided. For these safety reasons, it is BMW's policy to install winter tires in sets of four.
What kind of materials and designs are used in winter tires to make them work better in winter compared to all-season tires?
High quality winter tires, use specialized ice compounds that perform best at colder temperatures. The high silica tread compounds assist with traction on ice and hard-packed snow.
Will winter tires help me stop in slippery conditions?
A study conducted showed that a proper winter tire can improve braking up to 25 per cent over an all-season radial tire, and can improve collision avoidance by approximately 38 per cent.
Why shouldn't I keep winter tires on my car all year long?
Winter tires are designed with softer tread compounds so they can dig into snow and stick to ice at low temperatures. To get the optimal performance from the tires on your vehicle you should use the products as they are intended. While you could keep winter tires on all year, they typically have softer tread rubber and will wear out more quickly than an all-season tires.