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      10-31-2012, 12:15 PM   #1
dmppdx
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Wet weather performance for Summer Tires vs. A/S.

Maybe Ben can answer this questions, but I have always wondered what would get better traction in wet weather, a high performance summer tire like a PSS, or a high performance all season like a Michelin Pilot A/S? And if one offers better traction, is it significant?

This is assuming they are of equal size and it is not cold enough the summer tire starts really loosing performance and excluding standing water on the road, hydroplaning, snow, etc.

Just from looking at the testing done on tirerack.com, A/S tires seem to be show significantly closer test results between dry performance and wet performance than the summer tires. For summer tires, the test results show there is a significant difference in wet versus dry test results, and of course even though dry performance will not be anywhere close between the two types of tires, I was wondering if it would be close for wet conditions.

I'm just curious since comparing or testing tires between classes don't seem very common and i don't think I have seen any results.
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      11-01-2012, 10:59 AM   #2
ben@tirerack
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Given that you specify that the temperature is within the range where summer tires are effective, the summer tires will generally have better wet traction.

Dry traction, wet traction, and snow traction are like 3 points on a triangle, the more emphasis you put on one, it takes something away from the other two. Technology can mitigate this to an extent, but given a certain level of tech, the tradeoff applies.

Summer tires, by specializing only in wet and dry and ignoring snow, are able to do those two things better. Some tires specialize so much in dry that they may be worse than some all season tires when it comes to wet, but a balanced summer tire like the PSS will out handle an all-season tire in the rain.

Here are two sets of test results

All Season Test June 1 2011:
http://www.tirerack.com/tires/tests/...&affiliate=AW8

Summer Test June 14 2011:
http://www.tirerack.com/tires/tests/...&affiliate=AW8

The Pilot Sport AS+ does slightly out-brake the PSS in the wet 94ft to 96ft (directional pattern helping perhaps?) but if you look at lap times, which combine acceleration, braking, and cornering, 31.37 sec/lap for the PSS not only beats 32.92 sec wet lap of the AS+, it beats every other all-season wet lap in the test, AND every DRY lap time posted by the all-season group.

Please note that I did not include the data from the 2012 summer tire test. Wet conditions on the track this summer were extremely slippery and results from this summer should not be compared with others. The two tests I highlighted ran the same cars, same course configuration, and same group of drivers within a two week span.

The 2012 vs 2012 results tell the same story, but the AS+ was not included in the 2012 results, so I used the 2011 testing to answer the specific example you asked for. All tires were much worse in the wet in 2012 due to the conditions, but the PSS wet time was again better than the wet lap times of every tire in the 2012 UHP all-season test.
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      11-01-2012, 11:41 AM   #3
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Before i had the Michelin-PS,and now the Michelin PSS....
These Michelin Pilot super sport have a amazing grip in wet & dry,also in cornering !
About 15-20 % better than Michelin-PS.
Only negative point is.... they make a little more road noise !
Conclusion....when i need tires...Michelin PSS !!!
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      11-02-2012, 01:18 PM   #4
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Quote:
Originally Posted by ben@tirerack View Post
Given that you specify that the temperature is within the range where summer tires are effective, the summer tires will generally have better wet traction.

Dry traction, wet traction, and snow traction are like 3 points on a triangle, the more emphasis you put on one, it takes something away from the other two. Technology can mitigate this to an extent, but given a certain level of tech, the tradeoff applies.

Summer tires, by specializing only in wet and dry and ignoring snow, are able to do those two things better. Some tires specialize so much in dry that they may be worse than some all season tires when it comes to wet, but a balanced summer tire like the PSS will out handle an all-season tire in the rain.

Here are two sets of test results

All Season Test June 1 2011:
http://www.tirerack.com/tires/tests/...&affiliate=AW8

Summer Test June 14 2011:
http://www.tirerack.com/tires/tests/...&affiliate=AW8

The Pilot Sport AS+ does slightly out-brake the PSS in the wet 94ft to 96ft (directional pattern helping perhaps?) but if you look at lap times, which combine acceleration, braking, and cornering, 31.37 sec/lap for the PSS not only beats 32.92 sec wet lap of the AS+, it beats every other all-season wet lap in the test, AND every DRY lap time posted by the all-season group.

Please note that I did not include the data from the 2012 summer tire test. Wet conditions on the track this summer were extremely slippery and results from this summer should not be compared with others. The two tests I highlighted ran the same cars, same course configuration, and same group of drivers within a two week span.

The 2012 vs 2012 results tell the same story, but the AS+ was not included in the 2012 results, so I used the 2011 testing to answer the specific example you asked for. All tires were much worse in the wet in 2012 due to the conditions, but the PSS wet time was again better than the wet lap times of every tire in the 2012 UHP all-season test.
Thanks for the great info Ben! Wish I knew about the summer wet tests being slippery before I wrote an article about this exact topic...

And I can attest to the PSS performing great in the wet!
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      11-02-2012, 01:28 PM   #5
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Great information. Thanks dmppdx and ben@tirerack.

I was also curious as to what temperature Summer Performance Tires are not as effective. I don't plan on driving my M through snow, but do like to drive it through cold winter months, and was going to get a set of M+S rated tires.
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      11-02-2012, 03:32 PM   #6
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Quote:
Originally Posted by porshah View Post
Great information. Thanks dmppdx and ben@tirerack.

I was also curious as to what temperature Summer Performance Tires are not as effective. I don't plan on driving my M through snow, but do like to drive it through cold winter months, and was going to get a set of M+S rated tires.
The exact temperature will vary, and it is more of a spectrum than a specific cutoff temperature.

Here's a general breakdown based on my experience:
As you get into the 40s Farenheit the summer tires will become less effective than optimum, but still are ok to use.

Below 40 they start to lose more traction, and may feel a bit skittish in wet weather. I am doing this right now, and I leave a little extra safety margin if there is any moisture on the road. By this point the All-Season tires probably provide more grip.

Below freezing the loss of grip is even more noticeable, and if you get into any snow or freezing rain it can get quite scary.
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      11-02-2012, 10:11 PM   #7
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Thank you.
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