Safer Winter Driving -Think Ice and Snow Tires - You'll Be Happy You Did

By Thom Cannell
Detroit Bureau
The Auto Channel

Would you pay $1000 for a safer winter drive? Put another way, how much is your deductible, plus two weeks of car rental, plus an accident charged to your insurance, plus the emotional turmoil of an accident? How much is it worth to be able to have sufficient control to avoid an accident and possible injury on a snow-covered icy road surface?

That’s what we thought after driving a colleague’s summer tire-equipped car on icy roads and twice sliding desperately close to a curb and big bucks in front end damage. Modern ice and snow tires could have prevented those moments of panic.

Over the last 20 years, snow tires have almost disappeared thanks to “all-season” tires fitted on almost every vehicle sold. Consequently there are few readily available winter snow tires. The newest is Bridgestone’s Blizzak WS60 entering tire store showrooms later this year in September of 2007. Let’s look at a modern winter tire, what it costs to put a full set on your family car, and whether you should make the investment.

Blizzak ice and snow tires.

Available since 1992, the original ice and snow Blizzak has evolved into Bridgestone’s new WS60. This tire will be available in 38 sizes from 14” to 17” in diameter to fit a majority of family vehicles, cars and minivans. Other Blizzak models fit light trucks and SUVs.

The new Blizzak tire was chosen because of several proprietary technologies. One Bridgestone calls NanoPro-Tech that controls the interaction of the chemicals that make up the man-made rubber polymer, chemicals, and compounds like silica and carbon black that strengthen the tire. Carbon black and silica also make it last longer and grip the pavement better. Blizzak WS60 is two tires in one, a winter tire base with a special “Tube Multicell ™” compound cap. Tube Multicell is thousands of cells or pores that Bridgestone says resemble Swiss cheese under a microscope. These tubes wick water from the patch of rubber that meets the road for better grip, and “bite particles” held to tubes of the Multicell compound bite into ice and snow with extra grip. As the tire wears, additional pores are exposed to extend the life of the tread. The result is, the pores remove water that collects atop even icy pavement so the biting edges can grip more effectively. When 50% of the tire is worn, an indicator is exposed that lets you know that only 10% of the Multicell compound remains.

Selecting a package, how to get what you need.

We decided to get our tires from an on-line and print source, The Tire Rack, and being journalists, called to discuss proper selection. Matt Edmonds, Vice President, confirmed that the currently available Blizzak was a good selection for our needs, and added some critical information. “We only sell winter tires in sets of four, unless it is clearly a wear replacement of two tires,” he said. That keeps the co-efficient of friction similar on all wheels, critical on wet, icy, snow-covered, and dry pavement. He recommended buying wheels and tires, a more expensive choice that makes it easier, and cheaper in the long run. He also recommended that “snow tires should go on November first or at the first snow fall and come off no later than April 15 th,” That insures getting the maximum life out of your investment, which could be as few as two years with a heavy commuting schedule, or much longer if you accumulate minimal mileage. Next we selected our wheels and tires.

Each wheel and tire package has two important attributes: diameter, and wheel size. If the overall diameter of a wheel and tire combination is the same as original (within a few percent) and the wheel has the correct hub (center hole) and nut pattern, it should fit properly. This is most important if your car, truck, or SUV is fitted with an optional tire package. If that’s how your vehicle is equipped, either for performance or aesthetic reasons, a narrower and taller winter wheel and tire package might be your best bet. In our instance Matt suggested reducing the 17” wheel and summer high-performance tire to a 16” wheel with Blizzaks of an equivalent diameter, shipped mounted and balanced.

If you do this, the brake package, front brakes in particular, must have sufficient space inside the wheel and the tire have plenty of clearance in the wheel well. One clue to “minusing” or shrinking the wheel in your wheel and tire package is the base model tire and wheel combination. Critical information like this is one of the reasons to use a reputable and knowledgeable tire company like Tire Rack www.tirerack.com. They use sophisticated CAD (Computer Aided Design/Drafting) modeling to insure you get the correct fit.

Here’s our numbers as an example. The original 235/55 17 tire and alloy wheel package is being replaced with 215/65 R16 alloy wheels and tires. Notice the difference in wheel and tire sizes, yet they have identical diameters. Wheels, though of different size, provide requisite brake clearance.

Should you buy, and buy what?

As good as modern snow and ice tires are, not everyone needs a set of Blizzaks. Who does need snow tires, assuming you live where snow and ice are predictable?

It’s a relatively simple answer. If your car has one of the low-aspect high or ultra-high performance summer tires fitted to high performance automobiles and SUVs, you need snow tires. And if you own a powerful vehicle fitted with high or ultra-high performance tires that are “all weather” rated, snow tires a good idea. If this is mumbo-jumbo—unlikely if you own a Porsche, BMW, Jeep SRT-8, or something like it—there’s an easy test. If your tires look like rubber bands stretched around the wheels, regardless of any All Weather rating, you need snow tires. But if your All Weather tires look like a fat doughnut wrapped around the wheel and you don’t live in the Snow Belt, it’s less likely.

If you’re a numbers kind of person, aspect ratio (profile) is the second number on your tire’s sidewall, as in 215/65 R16, which is modest compared to the 295/30 R19s fitted to a new Audi R8 sports car, or the 305/30 R19s at the rear of a Porsche GT3. In order, you have the wall-to-wall dimension of an inflated tire and the second number is a metric percentage of that number. Our new 215/65 R16 tire is 215 mm wide and 65% is 139.75 mm from tread to rim. R means radial and the last number, 16” is the rim diameter.

If we have convinced you that even in February 2007 with two months of snow and ice remaining, that snow tires are a good idea there is one final consideration, do you have TPMS?

TPMS is the industry abbreviation for Federally mandated Tire Pressure Monitoring Systems that will be included on every 2008 model vehicle, and have been installed in some vehicles for the last 3-5 years. TPMS are supposed to insure that you never drive on under inflated tires — which are dangerous and cost you money in extra fuel use. (Michelin Tire Company measures prove that fully 20% of your fuel is required just to make the wheels roll and under inflated tires use much more fuel.)

There are two different kinds of TPMS that attempt to insure your tires are correctly inflated. A passive system uses mathematics to generate numbers from your ABS (anti-lock brake) sensors. This inexpensive method infers tire pressure from ABS sensor data; a deflated tire rolls more quickly than a fully inflated one. Matt pointed out a pitfall of this system. If your tires become uniformly under inflated they all roll the same and a passive system won’t report the danger. This could happen two ways; through the natural 1 psi per month loss that occurs as air molecules diffuse through the tire itself, or the 1 psi per 10°F loss that happens from cold.

What, cold cause tires to deflate? Yes, tires loose 1 psi for every 10° of temperature drop. At TheAutoChannel.com we frequently have test cars delivered. And lately, as temperatures plummeted, every garage-checked car soon developed low tire pressure! 32 psi in a 50°F garage quickly becomes 27 psi or less outside on mornings when the mercury dips to zero. It’s yet another reason to check tire pressure monthly, before leaving home.

The other system, Direct Reading TPMS, has pressure sensors installed in each wheel. If you have a direct reading system on your car you must purchase TPMS sensors when purchasing both wheels and tires. This adds approximately $200 to your winter tire purchase. If you buy tires and mount them on your existing wheels, no worries.

Why would you buy a complete second set of winter wheels? In the long run it is cheaper as most tire stores charge at least $30 per wheel to dismount a tire, remount the other tire, and balance the two. That’s $120, twice a season when four brand new alloy wheels cost $300-400.

What did we buy, what did we pay?

With all of our data gathered, we opted for four currently available Blizzak REVO 1 tires ($91 each,) and took The Tire Rack’s suggestion to add wheels ($91 each) that look like original equipment with TPMS sensors ($51.50 each, with nut) for a grand total of $934 mounted and balanced. Shipping added another $78.84. (Tires alone, with shipping would have been $394.40.)

So yes, we would have paid $1,000 for wintertime peace of mind. Because of a short commute, and as we can quickly change wheels at the first and “last” snowfall, our investment should last four years. That’s $250 per year, well under any insurance deductible and much less hassle than making an insurance claim. Oh, changing the wheel/tire package took 13 minutes and everyone who now drives that vehicle has a feeling of control as Blizzaks bite the road. As Matt said, “In nasty winter weather you change your shoes, why not your tires?”