Trade Resources Industry Knowledge We Measure Snow-Traction Performance to Provide Expert Insights for Winter-Tire Ratings

We Measure Snow-Traction Performance to Provide Expert Insights for Winter-Tire Ratings

We are just thawing out after spending a few days testing tires at Jay Peak Resort in northern Vermont. No, we weren't skiing. We were measuring snow-traction performance in severe conditions to provide expert insights for our upcoming winter-tire ratings.

Adventures in Winter Tire Testing: What We Do for Ratings

Adventures in testing

Jay Peak almost always has great snow, and this year's cold weather ensured the conditions for tire testing stayed just right. We test at night for snow consistency, and the temperature hovered around 5° F most of time. Dressed in layers, we actually felt relatively comfortable. (From the warmth of home, check out our tire buying guide and Ratings.)

But when we decided to venture home, the weather had become very hostile with high winds and blistering cold temperatures. The temperature readout in our Subaru BRZ indicated -17° F that morning. I knew it was cold when I pushed the clutch in and it didn't immediately retract. Worse, we had parked our Ford F-450 diesel pickup and equipment trailer out in an open parking lot at a higher elevation, where the temperature fell to -22° F.

Not surprisingly, the truck wouldn't start—the diesel-fuel lines were frozen. Now what? Our plan was to fire up a generator to plug into the engine-block heater on the truck, hoping to thaw it out. More bad news: The generator wouldn't start and the portable backup generator we had was virtually frozen. No matter, we soon realized our pickup wasn't equipped with an engine-block heater, so nothing gained or loss here.

Time to implement Plan B. We bought a kerosene heater at local general store to thaw the engine and fuel lines. However, the heater required electricity to force the hot air out. Thankfully, our Infiniti JX had an outlet. But just as soon as we thought we were on a "hot" streak, the extension cord we had became too brittle to use.

Now what?

Plan C: We bowed our heads in shame and asked for help from the nice folks at Jay Peak.

After a few side glances and wisecracks, they agreed to tow our truck into one of their heated garage bays to thaw out. Which introduced another problem. How do we disconnect our fifth-wheel trailer? You see, the trailer's jack stanchions were nearly frozen and required three of us to crank them down in order to disengage the trailer from the truck. Once freed, the truck was ready for a rope tow, but with no engine power, the brakes and steering mandated major muscle. The driver was nearly exhausted by the time we made our way to the garage. (No jokes about muscle cars here, please.)

From that point on, things got brighter and warmer. A dose of fuel stabilizer and a steady blast of hot furnace air directed at the truck's engine thawed it out in about two hours. That's what it took for us to try a few cranks and finally hear the engine roar to life.

And just how did the tires perform in these frigid conditions? We can share a few details here.

Initial findings

We evaluated nine performance winter tire models and 21 ultra-high-performance (UHP) all-season tires on the rear-wheel drive BRZ and its twin, the Scion FR-S.

Our testing includes measuring the distance to accelerate from 5 to 20 mph. Tires with good snow traction need a relatively short distance to get up to speed. The average distance for the performance winter tires was just over 92 feet. All-season tires, collectively, took more than double that distance. One winter-tire standout was the Nokian Hakkapeliitta R2.

Also, Bridgestone told us that its WS70 tire was a "regular" winter tire—not a performance winter version. But we tested it anyway. Turns out it was very impressive, second only to the Nokian.

Our testing showed that all winter models delivered secure grip. It's was a mixed bag among UHP all-season tires, however. Some provided decent grip for casual driving on snow-covered roads, but others just plain disappointed us.

We'll be moving on to ride comfort and ice-braking tests soon and should have all our testing wrapped up for a report on Consumerreports.org in September.

Bottom line: Testing has shown that if you must travel in snowy climates, a set of winter tires make a big difference. These give the bite to go, stop, and corner—all things that most all-season tires don't do well when the snow flies, as many New Englanders have been reminded by winter storm Nemo.

Source: http://news.consumerreports.org/cars/2013/02/what-we-do-for-ratings-adventures-in-winter-tire-testing.html#comments
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Adventures in Winter Tire Testing: What We Do for Ratings
Topics: Auto Parts