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On the same type of test vehicle (2006 BMW E90 325i Sedan of which they have four) about a month apart, the Tire Rack managed to get better wet stopping distances out of the RE960AS than four different "summer" (read: "3-season") tires in the 225/45R17 size.
Erm . . . no. You have misread the Tire Rack test. The "summer" tires you refer to (and which Tire Rack tested in the tests you cite to) are most definitely
not 3-season tires. They fall into the category that Tire Rack calls "Extreme Performance Summer Tires" (different from Ultra High Performance or Maximum Performance). Here is Tire Rack's own definition of this specialized category:
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You want extreme dry street performance and are willing to trade some comfort and hydroplaning resistance to get it.
Not intended to be driven in snow or on ice, or at high speeds in deep standing water, these specially tuned tires combine big-block tread designs with aggressive tread compounds and reinforced internal constructions to emphasize dry road response, traction, handling and high speed capabilities for serious driving enthusiasts.
http://www.tirerack.com/tires/types/extremeperf.jsp
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GC4lunch is talking about generalities. Here we have actual testing results.
But in the bunch you refer to, there was not one single 3-season tire, your assertion to the contrary notwithstanding.
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http://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=71
BFGoodrich g-Force T/A KD: 98.1 ft
Bridgestone Potenza RE-01R: 92.1 ft
KUMHO ECSTA MX: 104.5 ft
Yokohama ADVAN Neova AD07: 91.6 ft
For instance, look at the first tire in that listing, the BFGoodrich g-Force T/A KD. You
do know that the "KD" in that designation means "killer dry" don't you? That's "dry":
D-R-Y.
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The g-Force T/A KD is designed to deliver BFGoodrich's Traction/Advantage to increase the performance capabilities of sports cars, sports coupes and performance sedans by providing remarkable dry road performance (hence the "D" in KD) . . ..
http://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=g-Force+T/A+KD
Car and Driver, in its comprehensive test published in the December 2005 issue, said the same thing:
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On a wet road, the g-Force is not so forgiving. Once you venture past the limits of adhesion and the tire begins to slide, you get a spooky feeling that resembles driving on ice, that is, you slide for a while before the tire regains grip. Geswein called the g-Force's wet-weather performance "not good" and "easy to overdrive in the wet." It finished last in two out of three wet-track tests.
This result was not a surprise because printed on the side of this tire are the letters "KD," which company employees told us stand for "killer dry."
http://www.caranddriver.com/features/10252/tire-test-the-quick-and-the-tread-page4.html
The Tire Rack "Extreme Performance" category is limited to tires optimized for
dry conditions; it is not news that those tires do no better in the wet than tires designed to stick to snow do. Note that BFGoodrich makes
another tire the model designation of which differs from the designation of the tire above by one letter:
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The BFGoodrich g-Force T/A KDW-2 (KDW for Key feature: Dry and Wet traction, the “2” is our addition and identifies that this is the second generation g-Force T/A KDW) is the Ultra High Performance Summer tire that was developed to provide a blend of a dramatic-looking, ultra high performance tread design with superior dry and wet road performance.
http://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=g-Force+T/A+KDW+2
Tire Rack has tested the KDW, but on a different car (Lexus IS) with a different wheel and tire size, and on a different date, so no meaningful comparison can be made between the tests of the KDW and the KD, much less between the KDW and the Bridgestone RE960AS.
Tire Rack's test of the Bridgestone Potenza RE960AS Pole Position to which you provided the URL was a test of four all-season tires against each other, which is a fair test. But you cannot extract the numbers from a test by one set of test engineers under the conditions on one date and weather conditions on a specific vehicle and compare them one-on-one with the results on another vehicle in a different size on another date with different weather conditions and different test engineers.
(Because the OEM Tire on the BMW that Tire Rack uses is a Goodyear RS-A, you can find by digging deep on the Tire Rack site a lot of tests of the RS-A compared to other all-season tires. The RS-A comes out with different results in different tests.)
The fact is, the goals of making a tire stick to snow and making a tire stop as well as possible on wet pavement are
opposing goals: a compromise is made for every tire, and the more the tire is designed to stick to the snow the less it will stick to wet pavement. You
must take something from the right pocket in order to put something in the left pocket. It is as if you were heading north on Interstate 55 in St. Louis, and you were choosing whether to go to San Francisco or to go to New York. Both are fine destinations, but you must choose whether to turn west or to turn east; you cannot (as Robert Frost said) take both roads and remain one traveler.
I know that, like Lucy van Pelt, you want it all now, but compromises are made in each and every tire design, and the compromise that must be made to give a tire snow traction inevitably degrades wet braking.
