Im deciding between Pirelli Cintuato P7 with a 700-A-A with a Pirelli PZero Nero with a 400-AA-A. Clearly the Pirelli Pzero's have a better traction rating, but clearly the P7's will last much longer in terms of treadwear. Do you guys know if there is a significant difference between an A and AA in terms of traction? My last set was Michelin Pilot MXM4's had a 300-A-A rating. They handled great, but towards the end of their life, horrible in rain, although I guess that only makes sense. Anyone know how much differences? Also, what would you choose? (only between p7 and pzero nero A/S). Only reason im getting Pirelli's is due to a good discount im getting. thanks!
Difference between A and AA traction ratings
- Thread starter Rolla07
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JHZR2
Staff member
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
Both are good tires.
Originally Posted By: Rolla07
Do you guys know if there is a significant difference between an A and AA in terms of traction?
Read this, if you haven't already:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=48
Basically, on asphalt, a tire needs to achieve above 0.47g in wet braking test to get the A rating, and above 0.54g to get the AA rating. While this is a significant difference, we really don't know what the exact results were for these two Pirelli tires you're considering. I mean, one could have scored 0.53g and the other could have scored 0.55g and it would have been enough to get a different rating, even though in reality this would be a fairly small difference.
Quote:
My last set was Michelin Pilot MXM4's had a 300-A-A rating. They handled great, but towards the end of their life, horrible in rain,
Are you referring to the fact that they began hydroplaning easily? If so, that's normal on balding tires. Hydroplaning is not something that the A/AA traction rating takes into account.
Do you guys know if there is a significant difference between an A and AA in terms of traction?
Read this, if you haven't already:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=48
Basically, on asphalt, a tire needs to achieve above 0.47g in wet braking test to get the A rating, and above 0.54g to get the AA rating. While this is a significant difference, we really don't know what the exact results were for these two Pirelli tires you're considering. I mean, one could have scored 0.53g and the other could have scored 0.55g and it would have been enough to get a different rating, even though in reality this would be a fairly small difference.
Quote:
My last set was Michelin Pilot MXM4's had a 300-A-A rating. They handled great, but towards the end of their life, horrible in rain,
Are you referring to the fact that they began hydroplaning easily? If so, that's normal on balding tires. Hydroplaning is not something that the A/AA traction rating takes into account.
Originally Posted By: JHZR2
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
Yeah just on Corolla. Wet traction is what I am more concerned with moreso than tire life, although if traction is a negligable diffeence, id take the longer lasting tires!
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
Yeah just on Corolla. Wet traction is what I am more concerned with moreso than tire life, although if traction is a negligable diffeence, id take the longer lasting tires!
JHZR2
Staff member
Originally Posted By: Rolla07
Originally Posted By: JHZR2
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
Yeah just on Corolla. Wet traction is what I am more concerned with moreso than tire life, although if traction is a negligable diffeence, id take the longer lasting tires!
Yeah, in theory AA will give you better wet braking performance and by extension, traction under all conditions. It may also give you worse MPGs and tread life. Everything is a compromise after all.
After having used a variety of AA and A traction tires, I cant say that Ive been able to tell a meaningful difference, FWIW.
Originally Posted By: JHZR2
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
Yeah just on Corolla. Wet traction is what I am more concerned with moreso than tire life, although if traction is a negligable diffeence, id take the longer lasting tires!
Yeah, in theory AA will give you better wet braking performance and by extension, traction under all conditions. It may also give you worse MPGs and tread life. Everything is a compromise after all.
After having used a variety of AA and A traction tires, I cant say that Ive been able to tell a meaningful difference, FWIW.
Different category products. Cinturato is an all season touring tire and Pzero is a high performance all season. P7 gets my vote.
Thanks for the info guys! Yeah, I am leaning towards the Cinturato's but the nero's have better wet traction... on the pirelli site they say the p7 is 4/5 for wet, and nero is 4.5/5. I think the .5 is not a big difference..
Originally Posted By: Rolla07
Thanks for the info guys! Yeah, I am leaning towards the Cinturato's but the nero's have better wet traction... on the pirelli site they say the p7 is 4/5 for wet, and nero is 4.5/5. I think the .5 is not a big difference..
Well Pirelli aren't going to slam their own tires.
Maybe find less partial reviews on tire rack?
I'd go with the "A" traction, you are going to be on the road with other commuters and they will set the pace anyway and slow down (too much) in the rain.
Thanks for the info guys! Yeah, I am leaning towards the Cinturato's but the nero's have better wet traction... on the pirelli site they say the p7 is 4/5 for wet, and nero is 4.5/5. I think the .5 is not a big difference..
Well Pirelli aren't going to slam their own tires.
Maybe find less partial reviews on tire rack?
I'd go with the "A" traction, you are going to be on the road with other commuters and they will set the pace anyway and slow down (too much) in the rain.
If wet traction concerns you, look at the Tirerack "test" on wet braking distance and compare. You will have to consider a common tire in both tests as a reference if the tests are done on different cars and at different times.
Originally Posted By: Quattro Pete
Basically, on asphalt, a tire needs to achieve above 0.47g in wet braking test to get the A rating, and above 0.54g to get the AA rating. While this is a significant difference, we really don't know what the exact results were for these two Pirelli tires you're considering. I mean, one could have scored 0.53g and the other could have scored 0.55g and it would have been enough to get a different rating, even though in reality this would be a fairly small difference.
This is why you have to be careful getting too excited over these ratings. As stated these tests are not even conducted on a car, it's a test rig. So your mileage may vary!!!!
Basically, on asphalt, a tire needs to achieve above 0.47g in wet braking test to get the A rating, and above 0.54g to get the AA rating. While this is a significant difference, we really don't know what the exact results were for these two Pirelli tires you're considering. I mean, one could have scored 0.53g and the other could have scored 0.55g and it would have been enough to get a different rating, even though in reality this would be a fairly small difference.
This is why you have to be careful getting too excited over these ratings. As stated these tests are not even conducted on a car, it's a test rig. So your mileage may vary!!!!
usually though AA is going to be a fairly to REALLY grippy tire and get mediocre to poor MPG.
A traction is a huge range... sometimes even crazy summer tires get A traction because they are super optimized for dry not wet.
I've had a 5-10% drop off(1-3mpg) in fuel economy with the kumho 4x vs the oem spec yokos that were optimized for fuel economy.
A traction is a huge range... sometimes even crazy summer tires get A traction because they are super optimized for dry not wet.
I've had a 5-10% drop off(1-3mpg) in fuel economy with the kumho 4x vs the oem spec yokos that were optimized for fuel economy.
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Originally Posted By: Rand
also A and AA are tested without ABS. on wet straight line braking(not even on a car).. so its not HUGELY relevant to car use. but is info none-the-less.
I'd still pick an AA over an A for ABS car, heck, 2 of my 3 cars have no ABS.
also A and AA are tested without ABS. on wet straight line braking(not even on a car).. so its not HUGELY relevant to car use. but is info none-the-less.
I'd still pick an AA over an A for ABS car, heck, 2 of my 3 cars have no ABS.
Originally Posted By: PandaBear
Originally Posted By: Rand
also A and AA are tested without ABS. on wet straight line braking(not even on a car).. so its not HUGELY relevant to car use. but is info none-the-less.
I'd still pick an AA over an A for ABS car, heck, 2 of my 3 cars have no ABS.
Yeah. Not to mention that if a tire has little grip to begin with, ABS isn't going to work miracles anyway.
Originally Posted By: Rand
also A and AA are tested without ABS. on wet straight line braking(not even on a car).. so its not HUGELY relevant to car use. but is info none-the-less.
I'd still pick an AA over an A for ABS car, heck, 2 of my 3 cars have no ABS.
Yeah. Not to mention that if a tire has little grip to begin with, ABS isn't going to work miracles anyway.
Originally Posted By: Rolla07
Im deciding between Pirelli Cintuato P7 with a 700-A-A with a Pirelli PZero Nero with a 400-AA-A. Clearly the Pirelli Pzero's have a better traction rating, but clearly the P7's will last much longer in terms of treadwear. Do you guys know if there is a significant difference between an A and AA in terms of traction? ... Also, what would you choose? (only between p7 and pzero nero A/S). Only reason im getting Pirelli's is due to a good discount im getting. thanks!
... Wet traction is what I am more concerned with moreso than tire life, although if traction is a negligable difference, id take the longer lasting tires!
You will have very poor wet traction whichever of those two tires you choose. As others have noted, the NHTSA test procedure for Traction tests only one thing, and that is wet braking. But the test is deeply flawed even for that specific factor, and it is a "cheat sheet" for the flaws of all-season tires. The tire under test is mounted on a trailer, not on a vehicle, and the trailer is towed on a level surface in a straight line; then a chuck is thrown into the trailer axle to LOCK the wheel that the tire is mounted on; then there is a mandatory "wait" of half a second before the decelerative force is measured.
Here is what the problem is, especially when testing all-season tires: what makes a tire an "all-season" tire is that the tread compound has been chemically designed so that -- unlike tires using unmodified tread rubber compounds -- the tread does not shed water. That modification was made so that the tire will ahdhere to -- have traction on -- snow, because, under the pressure of the car's weight, the snow melts to water at the molecular level (molecular melting is the same process that allows you to take fluffy snow and pack it into a snowball that will "stick together"). While that non-shedding of water works on snow, which can be packed, it has an adverse effect upon traction on just wet -- not snow-covered -- surfaces, because liquid water does not pack, but the molecules just slide over one another.
Now, the NHTSA test procedure, by locking the wheel, ensures that only the one small patch of the tire -- the contact patch -- stays at the bottom of the tire's rotation for the entire measurement period, and does not rotate away. Moreover, the required "wait" ensures that the water that was on the contact patch will be scrubbed away before the measurement will begin. So the problem with wet braking that all-season tires have -- the water-to-water interface working as a lubricant -- is completely masked by the testing procedure.
Note that ABS exacerbates the issue, as what ABS does is precisely release the brakes upon detecting incipient wheel lock-up. So when, in real-life, not the test procedure, an all-season tire starts to lock up as inevitably it will do, the ABS releases the brakes, and a car equipped with ABS will rotate a new freshly wet portion of the tread into the contact patch area.
Originally Posted By: JHZR2
After having used a variety of AA and A traction tires, I cant say that Ive been able to tell a meaningful difference, FWIW.
If the two sets of tires were both all-season tires, you should see no difference, because the water on the tread of an AA rated tire that is permitted to rotate will perform the same lubricating function as the water on the tread of an A rated tire that is allowed to rotate; it is only after the water is scrubbed off of the tread that the tread of an AA-rated all season tire can make a difference.
Originally Posted By: PandaBear
I'd still pick an AA over an A for ABS car, heck, 2 of my 3 cars have no ABS.
The AA tire is especially superior to an A tire on a car that lacks ABS. And, in the real world, where all surfaces are not level and all directions are not straight ahead, the traction of an AA-rated tire will aid the driver in directional control.
Im deciding between Pirelli Cintuato P7 with a 700-A-A with a Pirelli PZero Nero with a 400-AA-A. Clearly the Pirelli Pzero's have a better traction rating, but clearly the P7's will last much longer in terms of treadwear. Do you guys know if there is a significant difference between an A and AA in terms of traction? ... Also, what would you choose? (only between p7 and pzero nero A/S). Only reason im getting Pirelli's is due to a good discount im getting. thanks!
... Wet traction is what I am more concerned with moreso than tire life, although if traction is a negligable difference, id take the longer lasting tires!
You will have very poor wet traction whichever of those two tires you choose. As others have noted, the NHTSA test procedure for Traction tests only one thing, and that is wet braking. But the test is deeply flawed even for that specific factor, and it is a "cheat sheet" for the flaws of all-season tires. The tire under test is mounted on a trailer, not on a vehicle, and the trailer is towed on a level surface in a straight line; then a chuck is thrown into the trailer axle to LOCK the wheel that the tire is mounted on; then there is a mandatory "wait" of half a second before the decelerative force is measured.
Here is what the problem is, especially when testing all-season tires: what makes a tire an "all-season" tire is that the tread compound has been chemically designed so that -- unlike tires using unmodified tread rubber compounds -- the tread does not shed water. That modification was made so that the tire will ahdhere to -- have traction on -- snow, because, under the pressure of the car's weight, the snow melts to water at the molecular level (molecular melting is the same process that allows you to take fluffy snow and pack it into a snowball that will "stick together"). While that non-shedding of water works on snow, which can be packed, it has an adverse effect upon traction on just wet -- not snow-covered -- surfaces, because liquid water does not pack, but the molecules just slide over one another.
Now, the NHTSA test procedure, by locking the wheel, ensures that only the one small patch of the tire -- the contact patch -- stays at the bottom of the tire's rotation for the entire measurement period, and does not rotate away. Moreover, the required "wait" ensures that the water that was on the contact patch will be scrubbed away before the measurement will begin. So the problem with wet braking that all-season tires have -- the water-to-water interface working as a lubricant -- is completely masked by the testing procedure.
Note that ABS exacerbates the issue, as what ABS does is precisely release the brakes upon detecting incipient wheel lock-up. So when, in real-life, not the test procedure, an all-season tire starts to lock up as inevitably it will do, the ABS releases the brakes, and a car equipped with ABS will rotate a new freshly wet portion of the tread into the contact patch area.
Originally Posted By: JHZR2
After having used a variety of AA and A traction tires, I cant say that Ive been able to tell a meaningful difference, FWIW.
If the two sets of tires were both all-season tires, you should see no difference, because the water on the tread of an AA rated tire that is permitted to rotate will perform the same lubricating function as the water on the tread of an A rated tire that is allowed to rotate; it is only after the water is scrubbed off of the tread that the tread of an AA-rated all season tire can make a difference.
Originally Posted By: PandaBear
I'd still pick an AA over an A for ABS car, heck, 2 of my 3 cars have no ABS.
The AA tire is especially superior to an A tire on a car that lacks ABS. And, in the real world, where all surfaces are not level and all directions are not straight ahead, the traction of an AA-rated tire will aid the driver in directional control.
Originally Posted By: JHZR2
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
I'm something of a tire nut, but there are times when you can get OCD about this stuff. A Corolla? You're are not running Showroom Stock Sedan class are you? On the othe hand, good tires can really surprise you with much better handling. I'd never discourage you from getting something better than OEM. Once upon a time I got a set of real good tires for my old man's V6 Camry, at first he didn't like the "too direct" steering, (no good deed) after a week he was raving about they way he could get around interstate ramps.
On a corolla and accent? I think there will not be a discernable difference. You arent running 1.02g on a skidpad.
Both are good tires.
I'm something of a tire nut, but there are times when you can get OCD about this stuff. A Corolla? You're are not running Showroom Stock Sedan class are you? On the othe hand, good tires can really surprise you with much better handling. I'd never discourage you from getting something better than OEM. Once upon a time I got a set of real good tires for my old man's V6 Camry, at first he didn't like the "too direct" steering, (no good deed) after a week he was raving about they way he could get around interstate ramps.
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Originally Posted By: SteveSRT8
Originally Posted By: Quattro Pete
Basically, on asphalt, a tire needs to achieve above 0.47g in wet braking test to get the A rating, and above 0.54g to get the AA rating. While this is a significant difference, we really don't know what the exact results were for these two Pirelli tires you're considering. I mean, one could have scored 0.53g and the other could have scored 0.55g and it would have been enough to get a different rating, even though in reality this would be a fairly small difference.
This is why you have to be careful getting too excited over these ratings. As stated these tests are not even conducted on a car, it's a test rig. So your mileage may vary!!!!
So what does .47 vs .54 translate into stopping distances with a real car on a real road?
Originally Posted By: Quattro Pete
Basically, on asphalt, a tire needs to achieve above 0.47g in wet braking test to get the A rating, and above 0.54g to get the AA rating. While this is a significant difference, we really don't know what the exact results were for these two Pirelli tires you're considering. I mean, one could have scored 0.53g and the other could have scored 0.55g and it would have been enough to get a different rating, even though in reality this would be a fairly small difference.
This is why you have to be careful getting too excited over these ratings. As stated these tests are not even conducted on a car, it's a test rig. So your mileage may vary!!!!
So what does .47 vs .54 translate into stopping distances with a real car on a real road?
OK, a quick physics of tires lessson:
First, is that tires do not follow the classical friction theory. Tires develop their highest grip when slipping about 10% to 15%. The test in question is measuring the slide value.
Second is that the relationship between the peak wet value and the slide wet value using this test is about the same regardless of the tire.
And lastly, the test in question isn't really about measuring hydroplaning resistance. It's about measuring the non-hydroplaning portion of wet grip.
Is it applicable for ABS equipped vehicles? In the sense that the ABS system senses the point at which the tire locks up - and that the rating isn't a value but kind of a way to do a gross comparison - yes. But don't try to make too fine a point of it.
First, is that tires do not follow the classical friction theory. Tires develop their highest grip when slipping about 10% to 15%. The test in question is measuring the slide value.
Second is that the relationship between the peak wet value and the slide wet value using this test is about the same regardless of the tire.
And lastly, the test in question isn't really about measuring hydroplaning resistance. It's about measuring the non-hydroplaning portion of wet grip.
Is it applicable for ABS equipped vehicles? In the sense that the ABS system senses the point at which the tire locks up - and that the rating isn't a value but kind of a way to do a gross comparison - yes. But don't try to make too fine a point of it.
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