Being a transplant from the West Coast to the Midwest means you have to adapt to a few things. One of which is the weather. The Midwest has all four seasons and most SoCal residents miss out on a proper winter. Yet in the Midwest it's a way of life and, apart from increased heating bills and more substantial clothing, one of the biggest considerations is tires.
The Blizzak winter tire (left) has more sipes in each tread block to cut into the snow and ice. It also has wider, deeper grooves that hold the snow, which actually gives more grip, and the rubber is formulated to remain flexible at lower temps than all-season or summer tires.
The Blizzak winter tire (left) has more sipes in each tread block to cut into the snow and
When faced with buying summer and winter tires, it begs the question whether winter tires are really worth the extra expense. In reality, it's like asking a track junkie if DOT-R tires are worth it over summer street tires. If you regularly visit the track and want to accelerate, brake and corner better, the answer is a resounding "yes".
With tire technology often blurring the performance categories, there are summer tires that hold up well on track, and all-season tires that hold their own in light snow. However, if you want to put down your best lap times, you're not going to attempt it on street tires. Similarly, in snow you want to get through a blizzard with your family in one piece, so should you be risking it on all-seasons?
When it comes to tire technology, Bridgestone is definitely at the cutting edge. We currently use a set of Potenza RE970AS Pole Position tires on the 2002 BMW 325i Wagon that appeared in last month's (EC 12/12) supercharger installation.
While the Potenza is the company's newest, top-of-the-line, high-performance all-season tires, they're fine for anything other than deep snow. Previously, I'd assumed that an all-season could be used, being good in the dry and suitable for the snow. And under most conditions this is true, with them being easily as good as many older summer tires we've used in the wet and dry.
The 970AS Pole Positions can even handle light snow relatively well. But if you're driving in deep snow and ice, you'll want a real winter tire, which is where the highly rated Bridgestone Blizzak LM-60 comes in.
Not quite a studless snow tire, the LM-60 is designed specifically for performance cars in wintry conditions, with a mix of snow and ice as well as wet and dry conditions. It means you don't need to change wheels every time the weather breaks, but can fit them at the very first hint of snow and leave them on through the winter. The Blizzak is considered the specialist tire for snow conditions: adept in a variety of temperatures but still able to provide good feedback and low wear rates when the road surface dries out.
In the snow they give you far more security in terms of stopping distances and pulling away on icy surfaces. You still have to be smart about how you drive, but these are a great comprise for drivers who want to enjoy their car in all conditions.
The performance of the LM-60 comes down to its technology, with the small sipes increasing the number of cutting edges to improve the traction in snow and ice. The wider blocks enhance snow traction and the circumferential grooves aid water evacuation.
For three seasons a year we use 255/35 R18 Bridgestone 970AS Pole Position tires on 18x9" wheels, the extra width giving good lateral traction and braking in dry conditions. However, winter driving generally calls for a narrower contact patch to cut through the top surface. So we hunted down a set of 18x8" TSW Interlagos wheels. These are slightly narrower than we used before bugt only weigh 18.85 lb per corner and are rotary forged for extra strength, in case you should clout something under the snow.
They were fitted with 245/45 R18 Blizzak LM-60 tires, which would be slightly narrower and taller to gain a little more ground clearance. These seem to work fine in our local weather conditions, but we might be tempted to use a narrow 215 or 225 width if we experienced harsher winter conditions.
The first snow of the year was a decent one and we decided to compare the performance of the Pole Position tires to the Blizzaks to show you what sort of improvements you could expect with the correct rubber for the conditions.
On our way out to our "test track" we witnessed 12 accidents in our ten-mile trek, proving the need to be well equipped for the winter season.
Using the Racelogic VBox we'd accurately measure both acceleration and stopping distances, since pulling away from a stop, or moving to avoid an oncoming car can be equally as important as braking.
We'd conduct real-world acceleration tests of 0-25mph, since most people don't race to 60mph in wintry conditions. Obviously we left the traction control active since few people would switch it off in these conditions. The BMW DSC was surprisingly good at full-throttle starts in snow and gave us repeatable results. We'd also brake from the same speed, simulating a full ABS-inducing panic stop, which tends to happen at intersections, etc.
Our first 0-25mph acceleration runs on the Blizzak winter tires averaged out to 7.84sec or 136.9ft, while braking from 25mph came out to 55.9ft or 3.39sec.
We then swapped to the all-season wheels and tires to repeat the test. The car immediately started moving around a bit more but we were confident gentle inputs could maintain control.
Once we began testing, however, it was obvious that there was a big difference. On the 0-25mph acceleration runs we averaged only 11.61sec and a whopping 216.57ft. This is considerably slower than the Blizzaks and highlights your inability to get out of the way if an incident happens around you.
We used 18" TSW Interlagos wheels for our winter tires because they're both light and strong to withstand a long winter.
We used 18" TSW Interlagos wheels for our winter tires because they're both light and stro
While we thought the acceleration differences would be marginal, we knew the braking would be more significant. However, it wasn't as marked as expected. It took the Pole Position all-seasons 3.81sec to stop from 25mph in a distance of 82.65ft. This speaks to the efficiency of the BMW ABS system and yet we covered an additional 26.75ft during the extra 0.42sec on the brakes.
Think about that for a moment. It represents a panic stop, so picture yourself sliding almost 27ft into an intersection and the consequences could be horrific. That's an extra two car lengths, which means you are going to hit the car in front of you if they stop suddenly on winter tires.
When we first came to the Midwest, locals would chuckle when asked what winter tires they use on their family car. Without fail, I was told all-seasons were all you needed. But after these tests, I'll never question my decision again. And it certainly explains the dozen accidents we encountered on the first snow day of the year.
If you spend time choosing the right oil for your engine, the best software for the ECU and smartest wheels for each corner, why not spend a little more time and money getting the right tires for the conditions, rather than leaving it to lady luck each year?
potenza vs blizzak winter tire test
||11.61sec / 216.57ft
||3.81sec / 82.65ft
||15.42sec / 299.22ft
||7.84sec / 136.9ft
||3.39sec / 55.9ft
||11.23sec / 192.8ft