Originally Posted By: Quattro Pete
GC, I don't doubt there are some summer tires that are better than some all-seasons when it comes to wet braking. But you're generalizing. I can show you some summer tires that are in fact worse than some all-seasons when it comes to wet braking.
And I probably could show you some basketball point guards who weigh more than some American football offensive tackles. But among current model tires from major tire makers, the all-season tires -- because of the compromises that must be made to enable the tread to gain traction on snow -- will always have poor wet traction compared to any general purpose non-all-season tire that is operating within its design parameters. (The last qualifier acknowledges that there are subsets of special-purpose non-all-season tires that are designed for racing or for high speed driving in very hot conditions, but not for daily driving in temperate conditions.)
The specific test results that I cited from the British publication were not generalized, but compared the wet stopping distances of of the top tire models from each category in an objective test conducted by a German enthusiast magazine. And, yes, racing slicks generally perform poorly in wet braking.
Originally Posted By: Quattro Pete
Bridgestone RE760 (summer tire): stopping distance from 50 mph: 92.9 feet
Bridgestone RE960 (all-season): stopping distance from 50 mph: 87.6 feet
Where did you get those numbers? I had assumed (from the 50-0 reference) that you were quoting TireRack test results. (Because of the length of the TireRack test track, a more usual 60-0 test cannot be conducted, so the tests are 50-0 instead; the 50-0 number usually is a marker of a TireRack test.)
But the latest (2012 August 3) TireRack test of the current top Bridgestone all-season tire (RE970AS) showed a wet braking distance of 114.60 feet; the TireRack test eleven months earlier (2011 September 1) of the RE960AS showed a 50-0 wet braking distance of 107.50 feet, consistent with the RE970AS's 2012 result, but almost 23 percent longer than the wet stopping distance that you cited.
I expect that in a head-to-head test under identical conditions with the same test crew, the newer model RE970AS probably would stop shorter than the previous generation RE960AS, but variations between test results when tires are not tested by the same crew in a single session are to be expected. When the identical model of tire is tested several times by TireRack, there are often significant differences between the results test to test. Generally, I think that the relative results among tires within a single TireRack test session are reliable, however.
GC, I don't doubt there are some summer tires that are better than some all-seasons when it comes to wet braking. But you're generalizing. I can show you some summer tires that are in fact worse than some all-seasons when it comes to wet braking.
And I probably could show you some basketball point guards who weigh more than some American football offensive tackles. But among current model tires from major tire makers, the all-season tires -- because of the compromises that must be made to enable the tread to gain traction on snow -- will always have poor wet traction compared to any general purpose non-all-season tire that is operating within its design parameters. (The last qualifier acknowledges that there are subsets of special-purpose non-all-season tires that are designed for racing or for high speed driving in very hot conditions, but not for daily driving in temperate conditions.)
The specific test results that I cited from the British publication were not generalized, but compared the wet stopping distances of of the top tire models from each category in an objective test conducted by a German enthusiast magazine. And, yes, racing slicks generally perform poorly in wet braking.
Originally Posted By: Quattro Pete
Bridgestone RE760 (summer tire): stopping distance from 50 mph: 92.9 feet
Bridgestone RE960 (all-season): stopping distance from 50 mph: 87.6 feet
Where did you get those numbers? I had assumed (from the 50-0 reference) that you were quoting TireRack test results. (Because of the length of the TireRack test track, a more usual 60-0 test cannot be conducted, so the tests are 50-0 instead; the 50-0 number usually is a marker of a TireRack test.)
But the latest (2012 August 3) TireRack test of the current top Bridgestone all-season tire (RE970AS) showed a wet braking distance of 114.60 feet; the TireRack test eleven months earlier (2011 September 1) of the RE960AS showed a 50-0 wet braking distance of 107.50 feet, consistent with the RE970AS's 2012 result, but almost 23 percent longer than the wet stopping distance that you cited.
I expect that in a head-to-head test under identical conditions with the same test crew, the newer model RE970AS probably would stop shorter than the previous generation RE960AS, but variations between test results when tires are not tested by the same crew in a single session are to be expected. When the identical model of tire is tested several times by TireRack, there are often significant differences between the results test to test. Generally, I think that the relative results among tires within a single TireRack test session are reliable, however.
