By Drew Wikstrom
Here on the east coast the winter can be somewhat mild or it can be Nor'easter nasty.
Because of these meteorologically unpredictable winters what people believe about
winter tires tends to reflect the weather of the particular winter in question.
In any given winter season three general winter tire related questions get asked.
1) "Should I stay with my summer performance tires?" 2) "Would an all-season tire
suffice?" and 3) "What kind of winter tire should I get?" Let us explore these questions
in some detail.
“Should I stay with my summer performance tires?”
The short answer is no. Unless you live in a perpetually summery climate such as
Florida or southern California where the ambient temperature never drops below 50
degrees F and it never ever snows then summer tires are not a good choice for the
Summer tires were designed for warmer temperatures and high stress use. Because
of this they have very large stable tread blocks that are not good in inclement
weather. In addition the rubber compound does not maintain elasticity in cold weather.
What this means is that the grip level of the tire degrades drastically in cold
temperatures even on dry pavement. In the cold a summer tire becomes unpredictable
and feels "slippery" when cornering no matter what the weather. This problem is
compounded in wet or snowy conditions.
“Would an all-season tire suffice?”
The answer to this question is dependent upon several factors. One of which is the
driving habits of the user. All season tires tend to be compromised tires. They
work reasonably well in a variety of conditions but they do not excel in any one
With regard to winter travel the important compromises are the ones that weaken
the winter capabilities of the tires. In an effort to maintain some warm weather
performance an all-season tire will have a rubber compound that may not work as
well in the cold as true winter tire. This all-season rubber compound may also be
further compromised by a need to provide a certain amount of tread life thereby
eschewing traction in all conditions in favor of longevity. An all-season tire may
have a tread design that trades inclement weather performance for dry road performance
by having larger more stable tread blocks than a winter tire.
Anyone who is considering all-season tires for year round or winter use needs to
carefully examine their driving habits. If giving up performance to gain more tread
life and avoid the hassle of changing over to winter tires is acceptable; then it
may well be worth it to utilize all-season tires. Driver's who are very conscious
of the performance capabilities of their vehicle or who want the absolute best traction
they can get as a safety margin should not use all-season tires for winter travel
unless the climate dictates otherwise.
In some climates all-season tires may be preferable to winter tires because of the
temperature range they were designed to work in. In warmer climates where it may
only snow once or twice a year a winter tire would wear out very quickly where an
all-season tire would work very well by providing the appropriate levels of performance
“What kind of winter tire should I get?”
This is the most difficult question to answer because recommendations can vary greatly
depending on multiple variables. What is the climate? What are the driving habits
of the user? What type of vehicle? Where are the drive wheels? etc. The list of
variables can be excessive. Fortunately winter tires can be divided into 3 main
categories. High performance winter tires, severe winter tires, and ice tires.
High Performance Winter Tires
High performance (HP) winter tires are the winter equivalent to high performance
summer tires. They are designed to have as few dry road handling compromises as
possible. The rubber compound is designed with cold temperatures and high-speed
travel as a primary focus. HP winter tires are usually "H" (130mph) or "V" (149mph)
speed rated although some are "Q" (99mph) or "T" (118mph) speed rated.
The tread design is usually similar to a modern high performance summer tire; it
will have fairly large and stable main tread blocks. What differentiates an HP winter
tread from a summer tread is that these blocks are spaced farther apart creating
a larger "void" area to enhance the evacuation of water and slush from under the
contact patch. The main tread blocks will also be inundated with very small cuts
known as sipes.
Tread sipes create little biting edges that aid snow traction. They also allow displacement
of the boundary layer of water that is created as the tire contacts an ice or snow
surface. This is important because this boundary layer of water is a large part
of what makes winter travel slippery. This boundary layer of water is the same as
that produced by a ski or snowboard as it slides across a snow surface, or an ice
skate as it glides across a surface of ice.
HP winter tire manufacturers use a variety of methods in order to maintain tread
block stability for good wet and dry road handling. These methods may be, sipes
designed in interlocking patterns, tires with reduced tread depth, or stiffer more
durable rubber compounds, or rubber compounds enhanced with physical stiffening
agents such as nylon or glass fiber.
Durability is an important part of an HP winter tire because they are meant to withstand
sustained speeds and increased mileages on dry road vs. a more conventional winter
tire or an ice tire.
HP winter tires are generally used in urban or suburban areas where road maintenance
is at its highest and also in climates that are not excessively snowy even though
they may be very cold. Other HP winter tire users are those that drive mainly on
highways and for long distances during the winter months.
Severe Winter Tires
Severe winter tires are generally studless and provide excellent grip in many different
snow and slush conditions. The same basic design requirements of the HP winter tires
carry over to the severe winter tires with increased performance in inclement weather
and sacrificed performance in the dry.
When compared to HP winter tires a severe winter tire will use a softer rubber compound
and have more tread sipes. The rubber compound may use very advanced technology
such as micro cellular structures or other advanced rubber compounding techniques.
More emphasis is also placed on what is known as a "self cleaning tread design".
A self-cleaning tread design traps snow when the tire rolls over it and then releases
the snow so it can trap more on the next revolution. In this case snow on snow provides
traction when the snow is trapped between the tread blocks. The snow must then be
released so that it can get trapped again. If the tread blocks do not release the
snow the traction goes away.
The disadvantages to a severe winter tire depend on the tire. The category is very
broad and each tire manufacturer addresses a large variety of conditions. Some tires
specialize very heavily while others are more well rounded.
The main disadvantages to severe winter tires are decreased longevity and decreased
dry road performance when compared to HP winter tires.
Severe winter tire users are usually in more rural areas where roads may be snow
covered for most of the winter due to lack of road maintenance or excessive snowfall.
These users typically do not drive excess mileages on dry road or do a lot of high-speed
Ice tires are the most specialized winter tires. They are meant to perform well
only on ice. The category was created largely due to conditions encountered on the
northern island of Japan where the traffic is very slow and winter road conditions
are often glare ice. For the North American market these tires are largely unusable.
While they provide very good traction on snow and ice they handle very poorly at
even moderate speeds and provide very little feedback to the driver. In addition
they wear out so fast that in many cases the useful life of the tire spans only
one winter season.
The technology in these tires is the same as any of the others. Sometimes the tread
design is biased toward ice, in which case it does not work well in snow or slush.
In some ice tires the rubber compound is simply changed and an existing tread design
is used creating a tire that looks identical to another winter tire but is useful
only for driving on ice due to its highly specialized rubber compound.
Ice tires are for drivers that experience icy conditions and slow speeds.
All the major tire manufacturers make winter tires for nearly every category. Bridgestone,
Michelin, Pirelli, Yokohama, Continental, and Dunlop all have winter tires in at
least two categories. Besides the major tire manufacturers Finland's Nokian is widely
regarded as the foremost manufacturer in the area of winter tire technology. Which
tires are best for you depends on your climate, the prevalent road conditions in
your area and your driving.
When choosing winter tires only choose those that meet the tire industry's "severe
snow service" standard. These can be identified by an icon molded into the tire
sidewall that looks like a snowflake within a mountain. Only tires that meet or
exceed the industry snow traction test display this symbol. Do not be misled by
the old "M+S" (mud and snow rating) as it corresponds only to the "void" area of
the tread design and is usually found on all-season tires as well as winter tires.
When choosing tires consider the temperatures they were designed to operate in.
Also consider personal driving habits, geographic location and road maintenance.
These considerations should provide enough information to determine what tires are
the correct ones. The specific attributes of various tires can be found online at
any of the manufacturer's websites, at your local tire store, or a national retailer
such as The Tire Rack.
Whatever winter tire you choose, make sure you don't buy it too late in the season.
Winter tire production starts in the spring and some sizes sell out by November.
Buy early to avoid this supply problem.
Hopefully you now have a better understanding of winter tires and can make a more
informed decision about what tire to choose for the winter season. Happy motoring!